KR20170004826A - Copper foil with carrier, copper-clad laminate and printed wiring board - Google Patents

Abstract

The present invention provides a copper foil with a carrier capable of suppressing an increase in the peel strength of the carrier foil even when a high temperature and long thermal history is applied and having stabilized peel strength. To solve this problem, the present invention provides a copper foil with a carrier comprising a carrier foil, a release layer and an ultra-thin copper foil in this order. The release layer is composed of 5-carboxybenzotriazole (5CBTA) and/or 4-carboxybenzotriazole (4CBTA). A 5CBTA/4CBTA ratio, which is a ratio of the adhesion amount of 5-carboxybenzotriazole to the adhesion amount of 4-carboxybenzotriazole in the release layer, is 3.0 or more.

Description

TECHNICAL FIELD [0001] The present invention relates to a copper-clad laminate, a copper clad laminate, a copper clad laminate,

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

As a material for producing a printed wiring board, a copper foil with a carrier is widely used. The copper foil with a carrier is bonded to an insulating resin base material such as a glass-epoxy base material, a phenol base material, or a polyimide to form a copper-clad laminate by hot press forming and is used in the production of a printed wiring board.

The carrier-attached copper foil typically has a structure in which a carrier foil, a release layer, and an ultra-thin copper foil are provided in this order. As the release layer, an organic release layer containing an organic compound such as a nitrogen-containing compound is proposed in JP-A-11-317574. (1) A release layer is easily formed. (2) the peeling strength (A) between the ultra-thin copper foil and the support metal layer (hereinafter, carrier) is uniform and exhibits a low value compared to the peeling strength (B) of the ultra-thin copper foil after lamination to the substrate; (3) It is not necessary to use a mechanical polishing process and a pickling process to remove the inorganic material remaining on the surface of the ultra-thin copper foil. Therefore, the formation of the wiring pattern can reduce the number of processing steps (4) The peel strength (A) is small, but it is sufficient to prevent the ultra-thin copper foil from separating from the carrier during handling of the composite copper foil. (5) The composite copper foil is sufficient Exfoliation (6) The carrier can be separated from the ultra-thin copper foil even after lamination at a high temperature. (7) Since it is easy to remove the peeling layer remaining on the carrier, there are various advantages that it is easy to reuse the carrier.

In Patent Document 2 (Japanese Patent Application Laid-Open No. 2003-328178), a pickling solution containing 50 ppm to 2000 ppm of an organic agent is used to pick up and dissolve the surface of a carrier foil, and at the same time, A method for producing a copper foil with a carrier, which comprises forming an organic coating film as an organic peeling layer.

In either of Patent Documents 1 and 2, the use of carboxybenzotriazole (CBTA) as an organic agent for forming an organic peeling layer is disclosed. Carboxybenzotriazole (CBTA) is known to have two chemical structures of 5-carboxybenzotriazole (5CBTA) and 4-carboxybenzotriazole (4CBTA), but Patent Documents 1 and 2 disclose that 5CBTA and The description regarding 4CBTA is not integrated.

In recent years, in order to increase the mounting density of the printed wiring board and make it compact, multilayered printed wiring boards have been widely used. Such a multilayer printed wiring board has been used for the purpose of weight reduction and miniaturization in most of portable electronic apparatuses. In addition, the multilayer printed wiring board is required to further reduce the thickness of the interlayer insulating layer and to further reduce the weight thereof as a wiring board. Thus, in recent multilayer printed wiring board manufacturing methods, a manufacturing method using a coreless build-up method in which an insulating resin layer and a conductor layer are alternately stacked is employed without using a so-called core substrate.

Japanese Patent Application Laid-Open No. 11-317574 Japanese Patent Application Laid-Open No. 2003-328178

However, there has been a problem in that the peeling strength between the carrier foil and the ultra-thin copper foil can be significantly increased if a plurality of high-temperature and long-time thermal history is applied by multiple lamination in the coreless build-up method or the like. Therefore, there is a demand for a copper foil with a carrier in which the peeling strength between the carrier foil and the ultra-thin copper foil is unlikely to increase, that is, the peel strength is stabilized even when a high temperature or a long thermal history is applied.

The inventors of the present invention found that the 5CBTA / 4CBTA ratio, which is the ratio of the adhesion amount of 5-carboxybenzotriazole to the adhesion amount of 4-carboxybenzotriazole, in the release layer of the copper foil with a carrier is 3.0 or more, The increase of the peel strength of the carrier foil can be suppressed, that is, the peel strength is stabilized.

Therefore, an object of the present invention is to provide a copper foil with a carrier which can suppress an increase in the peel strength of the carrier foil even when a high temperature or a long thermal history is applied, that is, the peel strength is stabilized.

According to one aspect of the present invention, there is provided a carrier-coated copper foil having a carrier foil, a release layer and an ultra-

Wherein the release layer comprises 5-carboxybenzotriazole (5CBTA) and / or 4-carboxybenzotriazole (4CBTA), wherein the adhesion amount of 5-carboxybenzotriazole in the release layer is 4-carboxy And a 5CBTA / 4CBTA ratio of not less than 3.0, which is a ratio to the adhesion amount of benzotriazole, is provided.

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

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

carrier  Attached copper foil

The carrier-applied copper foil of the present invention comprises a carrier foil, a release layer and an ultra-thin copper foil in this order. The release layer comprises 5-carboxybenzotriazole (hereinafter referred to as 5CBTA) and / or 4-carboxybenzotriazole (hereinafter referred to as 4CBTA). The chemical structures of 4CBTA and 5CBTA are as follows.

The copper foil with a carrier of the present invention has a 5CBTA / 4CBTA ratio of 3.0 or more, which is the ratio of the adhesion amount of 5CBTA to the adhesion amount of 4CBTA in the release layer. Thus, 5CBTA is an essential component, while 4CBTA is an optional component. In any case, the carrier-bonded copper foil may employ a known layer structure other than the one employing the release layer peculiar to the present invention.

As described above, by setting the 5CBTA / 4CBTA ratio to 3.0 or more in the release layer of the copper foil with a carrier of the present invention, it is possible to suppress the rise of the peel strength of the carrier foil even if a thermal history of high temperature and long time is given , That is, the peel strength can be stabilized. In this regard, as described above, CBTA has been conventionally used in the organic release layer, but it is not yet known that the 5CBTA / 4CBTA ratio is set to 3.0 or more. As such, as far as the applicants know, commercially available CBTA mixtures contain 5CBTA and 4CBTA in a ratio of about 6: 4 (5CBTA: 4CBTA ratio), and the 5CBTA / 4CBTA ratio of the mixture is only about 1.5 . In the peeling layer using such a CBTA mixture having a low 5CBTA / 4CBTA ratio, when a plurality of high-temperature and long-time heat histories are applied by multiple lamination in the coreless build-up method or the like, peeling strength between the carrier foil and the ultra- . On the other hand, according to the present inventor's findings, the above problem can be solved unexpectedly by setting the 5CBTA / 4CBTA ratio to 3.0 or more in the release layer of the copper foil with a carrier. Therefore, the copper foil with a carrier of the present invention can be used in a lamination process of a printed wiring board such as a coreless build-up method in which thermal history of high temperature and long time is given plural times by stacking a plurality of times, (For example, 10 to 20 gf / cm) when the peel strength is high, i.e., before the peel strength is lowered. Therefore, the copper foil with a carrier of the present invention is very useful for a lamination process of a printed wiring board such as a coreless build-up method.

The release layer has a function of suppressing the peeling strength between the carrier foil and the ultra-thin copper foil to ensure the stability of the strength and to suppress the mutual diffusion which may occur between the carrier foil and the copper foil at the time of press molding at high temperature Layer. The release layer is generally formed on one side of the carrier foil, but it may be formed on both sides. The release layer is an organic release layer, and includes 5CBTA and, optionally, 4CBTA. The release layer may contain, in addition to 5CBTA and 4CBTA, other components known as components of the organic release layer.

The 5CBTA / 4CBTA ratio in the release layer is 3.0 or more, preferably 3.5 to 30. Within this range, stable peel strength can be further exerted. In addition, the release layer may be composed of only 5CBTA (not including 4CBTA).

The release layer preferably contains 5CBTA and, if present, 4CBTA in an amount of 3 mg / m 2 or more in total, more preferably 5 mg / m 2 or more, and further preferably 8 mg / m 2 or more. Although the upper limit value of the adhesion amount is not particularly limited, in order to improve the handling property of the copper foil with a carrier and further stabilize the peel strength, it is preferable that the release layer contains 5CBTA and 4CBTA when present in an adhesion amount of 80 mg / More preferably not more than 50 mg / m 2, still more preferably not more than 30 mg / m 2.

The release layer can be formed by bringing a CBTA solution containing 4CBTA into contact with at least one surface of the carrier foil by 5CBTA and optionally fixing the CBTA component to the surface of the carrier foil. It is preferable that the CBTA solution contains 50 to 6000 ppm of 5CBTA and 0 to 3000 ppm of 4CBTA and that the concentration ratio of 5CBTA / 4CBTA is 2 or more, more preferably 5CBTA to 300 to 800ppm and 4CBTA to 0 to 150ppm, / 4CBTA has a concentration ratio of 2 to 8. The liquid temperature of the CBTA solution is preferably in the range of 20 to 60 캜, more preferably 30 to 40 캜. The treatment time in the CBTA solution is preferably in the range of 5 to 120 seconds, more preferably 30 to 60 seconds. The contact of the carrier foil with the CBTA solution may be carried out by immersion in the CBTA solution, spraying of the CBTA solution, or dropping or dropping of the CBTA solution. The fixing of the CBTA to the surface of the carrier foil may be performed by adsorption or drying of the CBTA solution, electrodeposition of the CBTA component in the CBTA solution, and the like. For example, in the case of using a copper foil as the carrier foil, it is preferable that the separation layer is formed by simultaneously adsorbing the CBTA component while pickling the carrier foil. In that case, the CBTA solution preferably has a sulfuric acid concentration of 50 to 250 g / L and a copper concentration of 2 to 20 g / L, more preferably a sulfuric acid concentration of 100 to 200 g / L and a copper concentration of 5 to 15 g / L. By doing so, a metal complex can be formed from the eluted metal ions and the CBTA component while allowing the surface of the carrier foil to be pickled and dissolved, and it can be precipitated and adsorbed on the carrier foil. As a result, the adsorbent structure of the CBTA component to be precipitated and adsorbed becomes finer, and the CBTA component can be uniformly adsorbed as compared with the case where the adsorbent is contacted with the aqueous solution in which the CBTA component is dispersed and precipitated and adsorbed.

The carrier foil is a foil for supporting the ultra-thin copper foil and improving its handling property. Examples of the carrier foil include an aluminum foil, a copper foil, a stainless steel (SUS) foil, a resin film having a metal coating on its surface, and the like. The copper foil may be either a rolled copper foil or an electrolytic copper foil. The thickness of the carrier foil is typically 250 탆 or less, preferably 9 탆 to 200 탆.

The ultra-thin copper foil is not particularly limited as long as it has a known construction adopted for the ultra-thin copper foil with a carrier. For example, the ultra-thin copper foil may be formed by a wet film formation method such as an electroless copper plating method and an electrolytic copper plating method, a dry film formation method such as sputtering and chemical vapor deposition, or a combination thereof. The thickness of the ultra-thin copper foil is preferably from 0.1 to 7.0 탆, more preferably from 0.5 to 5.0 탆, and still more preferably from 1.0 to 3.0 탆.

It is preferable that the surface of the ultra-thin copper foil on the opposite side of the release layer is coarsened. That is, it is preferable that the one surface of the ultra-thin copper foil is subjected to a roughening treatment. By doing so, it is possible to improve the adhesion with the resin layer at the time of producing the copper clad laminate or the printed wiring board. This roughening treatment includes at least two plating processes including a burnt plating process for depositing and depositing fine copper particles on the ultra thin copper foil and a seal plating process for preventing the fine copper particles from coming off It is preferable that the plating is carried out according to a known plating method.

Another functional layer may be provided between the peeling layer and the carrier foil and / or the ultra-thin copper foil. An example of such another functional layer is an auxiliary metal layer. The auxiliary metal layer is preferably made of nickel and / or cobalt. By forming such an auxiliary metal layer on the surface side of the carrier foil and / or on the surface side of the ultra-thin copper foil, mutual diffusion that may occur between the carrier foil and the ultra-thin copper foil during hot- The stability of the peel strength can be secured. The thickness of the auxiliary metal layer is preferably 0.001 to 3 mu m.

Depending on the desire, the ultra thin copper foil may be subjected to anti-corrosive treatment. The rust-preventive treatment preferably includes a plating treatment using zinc. The plating process using zinc may be either a zinc plating process or a zinc alloy plating process, and the zinc alloy plating process is particularly preferably a zinc-nickel alloy process. The zinc-nickel alloy treatment may be a plating treatment containing at least Ni and Zn, and may further include other elements such as Sn, Cr, and Co. The ratio of Ni / Zn in the zinc-nickel alloy plating is preferably 1.2 to 10, more preferably 2 to 7, and still more preferably 2.7 to 4 in mass ratio. It is preferable that the anti-rust treatment further includes a chromate treatment. It is more preferable that the chromate treatment is performed on the surface of the plating containing zinc after the plating treatment with zinc. By doing so, the anti-rust property can be further improved. A particularly preferable rust-preventive treatment is a combination of a zinc-nickel alloy plating treatment and a subsequent chromate treatment.

Optionally, the surface of the ultra-thin copper foil may be treated with a silane coupling agent to form a silane coupling agent layer. As a result, it is possible to improve the moisture resistance, chemical resistance, adhesion with the adhesive, and the like. The silane coupling agent layer can be formed by applying a silane coupling agent with dilution and drying. Examples of the silane coupling agent include epoxy functional silane coupling agents such as 4-glycidylbutyltrimethoxysilane and? -Glycidoxypropyltrimethoxysilane, or? -Aminopropyltrimethoxysilane, N-? ( Aminopropyltrimethoxysilane, N-3- (4- (3-aminopropoxy) butoxy) propyl-3-aminopropyltrimethoxysilane, N-phenyl- An amino functional silane coupling agent such as silane coupling agent, an amino functional silane coupling agent such as silane coupling agent, an amino functional silane coupling agent such as silane coupling agent, or a silane coupling agent such as a mercapto functional silane coupling agent such as γ-mercaptopropyltrimethoxysilane or an olefin functional silane coupling agent such as vinyltrimethoxysilane or vinylphenyltrimethoxysilane Or an acryl functional silane coupling agent such as γ-methacryloxypropyltrimethoxysilane, or an imidazole functional silane coupling agent such as imidazole silane, or a triazine functional silane coupling agent such as triazinilane .

Tie Laminates

The carrier-coated copper foil of the present invention is preferably used for producing a copper-clad laminate for printed wiring boards. That is, according to a preferred embodiment of the present invention, there is provided a copper clad laminate obtained by using the copper foil with a carrier. This copper-clad laminate comprises the copper foil with a carrier of the present invention and a resin layer provided in close contact with the ultra-thin copper foil of the copper foil with a carrier. The carrier-attached copper foil may be provided on one side of the resin layer or on both sides. The resin layer comprises a resin, preferably an insulating resin. The resin layer is preferably a prepreg and / or a resin sheet. The prepreg is a generic name of a composite material obtained by impregnating a base material such as a synthetic resin plate, a glass plate, a glass woven fabric, a glass nonwoven fabric, or paper with a synthetic resin. Preferable examples of the insulating resin include an epoxy resin, a cyanate resin, a bismaleimide triazine resin (BT resin), a polyphenylene ether resin, and a phenol resin. Examples of the insulating resin constituting the resin sheet include insulating resins such as epoxy resin, polyimide resin and polyester resin. Further, the resin layer may contain filler particles composed of various inorganic particles such as silica and alumina from the viewpoint of improving the insulating property and the like. The thickness of the resin layer is not particularly limited, but is preferably 1 to 1000 占 퐉, more preferably 2 to 400 占 퐉, and still more preferably 3 to 200 占 퐉. The resin layer may be composed of a plurality of layers. A resin layer such as a prepreg and / or a resin sheet may be provided in the ultra-thin copper foil with a carrier through a primer resin layer previously coated on the surface of the copper foil.

print Wiring board

The copper foil with a carrier of the present invention is preferably used in the production of a printed wiring board. That is, according to a preferred embodiment of the present invention, there is provided a printed wiring board obtained using the copper foil with a carrier. The printed wiring board according to the present embodiment comprises a layer structure in which a resin layer and a copper layer are laminated in this order. The resin layer is as described above for the copper clad laminate. In any case, a known layer structure can be employed for the printed wiring board. As specific examples of the printed wiring board, a single-sided or double-sided printed wiring board formed by forming a laminate obtained by adhering the ultra-thin copper foil of the present invention to one side or both sides of a prepreg and curing it, or a multilayered printed wiring board obtained by multilayering these can be given. As another specific example, a flexible printed wiring board, a COF, a TAB tape, or the like which forms a circuit by forming the ultra-thin copper foil of the present invention on a resin film can be used. As another specific example, the resin-coated copper foil (RCC) coated with the resin layer described above is formed on the ultra-thin copper foil of the present invention, the resin layer is laminated on the above-mentioned printed wiring board as an insulating adhesive layer, Or a buildup circuit in which a circuit is formed by a method such as a modified semiaddition (MSAP) method or a subtractive method, or a build-up circuit in which a circuit is formed by a semiadaptive (SAP) method by removing an ultra- A direct build-up-on-wafer in which a lamination of a resin-coated copper foil and a circuit formation are alternately repeated on a wiring board and a semiconductor integrated circuit. The copper foil with a carrier of the present invention can be preferably used for a manufacturing method using a coreless build-up method in which an insulating resin layer and a conductor layer are alternately laminated without using a so-called core substrate.

[Example]

The present invention will be described more specifically with reference to the following examples.

Examples 1-9

The manufacture and evaluation of the copper foil with a carrier were carried out as follows.

(1) Preparation of carrier foil

As the carrier foil, an electrolytic copper foil (Class-III made by Mitsugi Chemical Industries Co., Ltd.) not subjected to coarsening treatment and anti-rust treatment with a thickness of 18 탆 was prepared.

(2) Formation of release layer

The electrode surface side of the pickled carrier foil was immersed in a CBTA aqueous solution having a sulfuric acid concentration of 150 g / L and a copper concentration of 10 g / L, containing 5CBTA and / or 4CBTA, 4, 7, and 8) or 40 ° C (Examples 5, 6, and 9) for 30 seconds to adsorb the CBTA component to the electrode surface of the carrier foil. Thus, a CBTA layer was formed as an organic release layer on the surface of the electrode surface of the carrier foil. Example 7 is a composition corresponding to Example 3 disclosed in Patent Document 2 (Japanese Patent Application Laid-Open No. 2003-328178).

[Table 1]

(3) Formation of auxiliary metal layer

The carrier foil having the organic release layer formed thereon was immersed in a solution having a nickel concentration of 20 g / L prepared using nickel sulfate to prepare a carrier foil having an adhesion amount equivalent to 0.001 占 퐉 in thickness at a liquid temperature of 45 占 폚, a pH of 3 and a current density of 5 A / Nickel was adhered onto the organic release layer. Thus, a nickel layer was formed as an auxiliary metal layer on the organic peeling layer.

(4) Formation of ultra-thin copper foil

The carrier foil having the auxiliary metal layer formed thereon was immersed in a copper solution having the composition shown below and electrolyzed at a solution temperature of 45 캜 and a current density of 5 to 30 A / dm 2 to form an ultra-thin copper foil having a thickness of 3 탆 on the auxiliary metal layer.

≪ Composition of Solution >

- Copper concentration: 65 g / L

- sulfuric acid concentration: 150 g / L

(5) Harmonization processing

The surface of the ultra-thin copper foil thus formed was subjected to a roughening treatment. This roughening treatment is composed of a bunt plating step for depositing and depositing fine copper particles on the ultra-thin copper foil and a seal plating step for preventing the fine copper particles from coming off. In the copper plating step, an acidic copper sulfate solution containing 18 g / L of copper and 100 g / L of sulfuric acid was used to conduct coarsening treatment at a liquid temperature of 25 DEG C and a current density of 10 A / dm2. In the subsequent seal plating step, electrodeposition was carried out under a smooth plating condition at a liquid temperature of 45 DEG C and a current density of 15 A / dm < 2 > using a copper solution containing 65 g / L of copper and 150 g / L of sulfuric acid.

(6) Rust treatment

Both sides of the copper foil with a carrier after the roughening treatment were subjected to anti-rust treatment comprising an inorganic anti-rust treatment and a chromate treatment. First, as the inorganic anticorrosive treatment, a pyrophosphoric acid bath was used, and a zinc pyrophosphate solution containing zinc pyrophosphate at a concentration of 80 g / L of potassium pyrophosphate, a zinc concentration of 0.2 g / L, a nickel concentration of 2 g / L, a liquid temperature of 40 DEG C, and a current density of 0.5 A / Alloy rust prevention treatment was performed. Then, as a chromate treatment, a chromate layer was further formed on the zinc-nickel alloy rust-preventive treatment. The chromate treatment was carried out at a chromic acid concentration of 1 g / L, a pH of 11, a solution temperature of 25 캜, and a current density of 1 A / dm 2.

(7) Treatment with silane coupling agent

The copper foil subjected to the rust-preventive treatment was washed with water and then immediately subjected to a silane coupling agent treatment to adsorb a silane coupling agent on the rust-inhibited layer on the roughened surface. This silane coupling agent treatment was carried out by using a solution of pure water as a solvent and a 3-aminopropyltrimethoxysilane concentration of 3 g / L and blowing the solution on the roughened surface with a shower to perform adsorption treatment. After the adsorption of the silane coupling agent, moisture was finally produced by an electric heater to obtain a copper foil with a carrier.

(8) Evaluation of copper foil with carrier

The obtained copper foil with a carrier was subjected to the following evaluations.

<Analysis of release layer>

The carrier foil was peeled from the copper foil with a carrier. The peeled carrier foil and the ultra-thin copper foil were immersed in 1 mol / L hydrochloric acid at 40 DEG C for 60 minutes to extract CBTA. At that time, by masking the surface opposite to the peeling layer of the carrier foil and the ultra-thin copper foil, only the surface in contact with the peeling layer was attached to the extraction of CBTA. The CBTA-containing extract thus obtained was analyzed by high performance liquid chromatography (HPLC LC10 series, Shimadzu Seisakusho Co., Ltd.), and the concentrations of 5CBTA and 4CBTA were measured to determine the amount of adhesion of 5CBTA (mg / (Mg / m 2), the total amount of adhesion of CBTA (mg / m 2) and the ratio of 5CBTA / 4CBTA were calculated. The results are shown in Table 2.

<Measurement of Peel Strength>

First, the peeling strength in the state of the copper foil with a carrier was measured as follows. A double-faced tape was affixed to the ultra-thin copper foil side of the copper foil with a carrier, and the double-side tape was affixed to the substrate and fixed to obtain a measurement sample. The peel strength RS ₀ (gf / cm) in the state of peeling the carrier foil was measured for this measurement sample in accordance with JIS C 6481-1996. At this time, the measurement width was 50 mm and the measurement length was 20 mm.

Then, the peel strength after one or two hot pressing was measured as follows. As a resin substrate, a prepreg having a thickness of 100 占 퐉 (GHPL830NX-A, manufactured by Mitsubishi Gas Chemical Co., Ltd.) was prepared. The copper foil with a carrier was laminated on the resin base material so that the extremely thin copper foil side was in contact with the resin base material. The hot press forming was performed once or twice for 60 minutes at a pressure of 2.5 MPa and at a temperature of 230 占 폚, A copper clad laminate sample was obtained. For the copper-clad laminate sample, the carrier foil was peeled off from the ultra-thin copper foil laminated on the resin substrate surface according to JIS C 6481-1996, and the peel strength RS ₁ (after one hot press) and the peel strength RS ₂ (Gf / cm) was measured. At this time, the measurement width was 50 mm and the measurement length was 20 mm. (%) Of the peel strength was calculated by multiplying the ratio (RS ₂ -RS ₀ ) / RS ₀ ) of the peel strength RS ₂ to the peel strength RS ₀ of the state before the hot pressing and the peel strength RS ₂ of the hot press 2 times. The results are shown in Table 2.

[Table 2]

* Represents a comparative example.

Claims (7)

A copper foil, a carrier foil, a release layer, and an ultra-thin copper foil in this order,
Wherein the release layer comprises 5-carboxybenzotriazole (5CBTA) and / or 4-carboxybenzotriazole (4CBTA), wherein the adhesion amount of 5-carboxybenzotriazole in the release layer is 4-carboxy Carbonaceous copper foil with a 5CBTA / 4CBTA ratio of 3.0 or more, which is a ratio to the amount of benzotriazole deposited. The method according to claim 1,
Wherein the 5CBTA / 4CBTA ratio is 3.5 to 30. The method according to claim 1,
Wherein the release layer comprises 5-carboxybenzotriazole (5CBTA) and, if present, 4-carboxybenzotriazole (4CBTA) in an amount of adhesion of not less than 3 mg / m 2 in total. The method according to claim 1,
Wherein the release layer comprises 5-carboxybenzotriazole (5CBTA) and, if present, 4-carboxybenzotriazole (4CBTA) in an adhesion amount of 80 mg / m 2 or less in total. The method according to claim 1,
Further comprising an auxiliary metal layer between the peeling layer and the carrier foil and / or the ultra-thin copper foil. A copper-clad laminate comprising the copper foil with a carrier according to any one of claims 1 to 5. A method for producing a printed wiring board using the copper foil with a carrier according to any one of claims 1 to 5.