KR102316978B1 - Copper foil with carrier, copper-clad laminate and printed wiring board - Google Patents

Abstract

This invention provides the copper foil with a carrier which can suppress the raise of the peeling strength of carrier foil even if it provides a high temperature and a long-time thermal history, ie, the peeling strength stabilized.
In order to solve this subject, as copper foil with a carrier provided with carrier foil, a peeling layer, and ultra-thin copper foil in this order, a peeling layer is 5-carboxybenzotriazole (5CBTA) and/or 4-carboxybenzo Copper foil with a carrier which consists of triazole (4CBTA) and is a ratio of 5CBTA/4CBTA ratio with respect to the adhesion amount of 4-carboxybenzotriazole of the adhesion amount of 5-carboxybenzotriazole in a peeling layer 3.0 or more.

Description

COPPER FOIL WITH CARRIER, COPPER-CLAD LAMINATE AND PRINTED WIRING BOARD

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

As a material for printed wiring board manufacture, copper foil with a carrier is used widely. Copper foil with a carrier is bonded by hot press molding with insulating resin base materials, such as a glass-epoxy base material, a phenol base material, and polyimide, to become a copper clad laminated board, and is used for manufacture of a printed wiring board.

The copper foil with a carrier typically has a structure provided with carrier foil, a peeling layer, and ultra-thin copper foil in this order. As this release layer, Patent Document 1 (Japanese Patent Application Laid-Open No. 11-317574) proposes an organic release layer containing an organic compound such as a nitrogen-containing compound, (1) easy to form the release layer; (2) The peel strength (A) between the ultra-thin copper foil and the support metal layer (hereinafter, carrier) is uniform, and shows a low value compared to the peel strength (B) of the ultra-thin copper foil after lamination on the substrate, (3) inorganic Since no material is used, a mechanical polishing step and pickling step for removing the inorganic material remaining on the surface of the ultra-thin copper foil are not required. Therefore, the formation of the wiring pattern reduces 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 after lamination to the substrate It has peeling strength (B), and ultra-thin copper foil does not peel from a base material at the time of processing to a printed wiring board, (6) carrier can be separated from ultra-thin copper foil even after lamination|stacking at high temperature, (7) ) Since it is easy to remove the peeling layer remaining on the carrier, it is disclosed that there are various advantages of reusing the carrier easily.

Further, in Patent Document 2 (Japanese Patent Laid-Open No. 2003-328178), pickling is adsorbed by using a pickling solution containing 50 ppm to 2000 ppm of an organic agent, pickling and dissolving the surface of carrier foil while simultaneously adsorbing the organic agent. The manufacturing method of copper foil with a carrier including forming an organic film as an organic peeling layer is disclosed.

In any one of Patent Documents 1 and 2, use of carboxybenzotriazole (CBTA) is disclosed as an organic agent for forming an organic release layer. Regarding carboxybenzotriazole (CBTA), it is known that there are two chemical structures of 5-carboxybenzotriazole (5CBTA) and 4-carboxybenzotriazole (4CBTA), but in Patent Documents 1 and 2, 5CBTA and There is no description of 4CBTA.

By the way, in recent years, in order to raise the mounting density of a printed wiring board and to reduce the size, multilayering of a printed wiring board has come to be performed widely. Such a multilayer printed wiring board is used in most portable electronic devices for the purpose of weight reduction and size reduction. And reduction of the additional thickness of an interlayer insulating layer and further weight reduction as a wiring board are calculated|required by this multilayer printed wiring board. Then, the manufacturing method using the coreless buildup method in which an insulating resin layer and a conductor layer are laminated|stacked alternately is employ|adopted for the manufacturing method of a multilayer printed wiring board in recent years, without using a so-called core board.

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

However, there was a problem that the peel strength between the carrier foil and the ultra-thin copper foil could be significantly increased when a plurality of times of high temperature and a long time heat history were applied by lamination in a plurality of times in a coreless build-up method or the like. For this reason, even if it provides a high temperature and a long-time heat history, the peeling strength between carrier foil and ultra-thin copper foil is hard to rise, ie, the copper foil with a carrier in which peeling strength was stabilized is calculated|required.

The present inventors this time, in the peeling layer of copper foil with a carrier, the ratio with respect to the adhesion amount of 4-carboxybenzotriazole of 5-carboxybenzotriazole WHEREIN: By making 5CBTA/4CBTA ratio 3.0 or more, high temperature and long time Even if it gave the thermal history of , the rise of the peeling strength of carrier foil could be suppressed, ie, the knowledge that peeling strength was stabilized was acquired.

Therefore, the objective of this invention is providing the copper foil with a carrier which can suppress the raise of the peeling strength of carrier foil even if it provides a high temperature and a long-time heat history, ie, the peeling strength stabilized.

According to one aspect of the present invention, 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 contains 5-carboxybenzotriazole (5CBTA) and/or 4-carboxybenzotriazole (4CBTA), and the amount of 5-carboxybenzotriazole attached to the release layer is 4-carboxy The copper foil with a carrier in which 5CBTA/4CBTA ratio which is ratio with respect to the adhesion amount of benzotriazole becomes 3.0 or more is provided.

According to another aspect of this invention, the copper clad laminated board obtained using the copper foil with a carrier of the said aspect is provided.

According to another one aspect of this invention, the printed wiring board obtained using the copper foil with a carrier of the said aspect is provided.

carrier Attached copper foil

The copper foil with a carrier of this invention was equipped with carrier foil, a peeling layer, and ultra-thin copper foil in this order. The release layer contains 5-carboxybenzotriazole (hereinafter referred to as 5CBTA) and/or 4-carboxybenzotriazole (hereinafter referred to as 4CBTA). The chemical structural formulas of 4CBTA and 5CBTA are as follows.

As for the copper foil with a carrier of this invention, 5CBTA/4CBTA ratio which is ratio with respect to the adhesion amount of 4CBTA of the adhesion amount of 5CBTA in a peeling layer is 3.0 or more. Therefore, it can be said that 5CBTA is an essential component, while 4CBTA is an optional component. In any case, the copper foil with a carrier can employ|adopt well-known layer structure except employ|adopting the peeling layer peculiar to this invention.

Thus, in the peeling layer of the copper foil with a carrier of this invention, by making 5CBTA/4CBTA ratio 3.0 or more, even if it provides high temperature and a long-time thermal history unexpectedly, a raise of the peeling strength of carrier foil can be suppressed. , that is, the peel strength can be stabilized. Although CBTA has been conventionally used for this point and an organic peeling layer as mentioned above, what made 5CBTA/4CBTA ratio 3.0 or more is not known yet. As far as the applicant is aware, a commercially available CBTA mixture contains 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 a peeling layer using a CBTA mixture with such a low 5CBTA/4CBTA ratio, if multiple times of high temperature and long heat history are applied by multiple times of lamination by a coreless build-up method, the peel strength between the carrier foil and the ultra-thin copper foil can be significantly increased. there was a problem that On the other hand, according to this knowledge of this inventor, the peeling layer of copper foil with a carrier WHEREIN: The said problem can be eliminated unexpectedly by making 5CBTA/4CBTA ratio 3.0 or more. Therefore, the copper foil with a carrier of this invention is a state (high temperature and long-time thermal history) in the lamination process of printed wiring boards, such as a coreless build-up method, in which a high temperature and long-time thermal history is given several times by lamination|stacking several times. (before this is given), the rate of increase of the peel strength with respect to the peel strength is low, that is, a stable peel strength (for example, 10 to 20 gf/cm) can be exhibited. Therefore, it can be said that the copper foil with a carrier of this invention is very useful for lamination processes of printed wiring boards, such as a coreless build-up method.

The release layer weakens the peel strength between the carrier foil and the ultra-thin copper foil, ensures the stability of the strength, and also has a function of suppressing the interdiffusion that may occur between the carrier foil and the copper foil during press molding at a high temperature. is the floor Although it is common to provide a peeling layer in one surface of carrier foil, you may provide in both surfaces. The release layer is an organic release layer and contains 5CBTA and optionally 4CBTA. The release layer may contain other components known as components of the organic release layer other than 5CBTA and 4CBTA.

5CBTA/4CBTA ratio in a peeling layer is 3.0 or more, Preferably it is 3.5-30. If it is in such a range, it will become easy to exhibit stable peeling strength further. Moreover, the peeling layer may contain 5CBTA independently (does not contain 4CBTA).

The release layer preferably contains 5 CBTA and, if present, 4 CBTA in a total adhesion amount of 3 mg/m 2 or more, more preferably 5 mg/m 2 or more, still more preferably 8 mg/m 2 or more. The upper limit of the adhesion amount is not particularly limited, but for the improvement of handling properties of the copper foil with a carrier and further stabilization of the peel strength, the release layer contains 5CBTA and 4CBTA, if present, in a total adhesion amount of 80 mg/m 2 or less. It is preferable, More preferably, it is 50 mg/m<2> or less, More preferably, it is 30 mg/m<2> or less.

Formation of a peeling layer can be performed by making the CBTA solution containing 5CBTA and 4CBTA contact with the at least one surface of carrier foil, and fixing a CBTA component to the surface of carrier foil etc. The CBTA solution contains 50 to 6000 ppm of 5CBTA and 0 to 3000 ppm of 4CBTA, and a concentration ratio of 5CBTA/4CBTA is preferably 2 or more, more preferably 300 to 800 ppm of 5CBTA and 0 to 150 ppm of 4CBTA, 5CBTA The concentration ratio of /4CBTA is 2-8. It is preferable that the liquid temperature of a CBTA solution is the range of 20-60 degreeC, More preferably, it is 30-40 degreeC. The treatment time in the CBTA solution is preferably in the range of 5 to 120 seconds, more preferably 30 to 60 seconds. What is necessary is just to perform the contact to the CBTA solution of carrier foil by immersion to a CBTA solution, spraying of a CBTA solution, flowing thru|or dripping of a CBTA solution, etc. In addition, what is necessary is just to perform fixing to the surface of carrier foil of CBTA by adsorption|suction of a CBTA solution, drying, electrodeposition of the CBTA component in a CBTA solution, etc. For example, when using copper foil as carrier foil, it is preferable to perform formation of a peeling layer by adsorbing a CBTA component simultaneously, carrying out pickling process of carrier foil, In that case, CBTA solution is sulfuric acid concentration 50-250 g/ L and a copper concentration of 2 to 20 g/L are preferable, and more preferably a sulfuric acid concentration of 100 to 200 g/L and a copper concentration of 5 to 15 g/L. By carrying out in this way, a metal complex can be formed with the metal ion and CBTA component which eluted, carrying out pickling-dissolution of the surface of carrier foil, and it can be precipitated and adsorbed on carrier foil. As a result, the adsorption structure of the CBTA component to be adsorbed by precipitation becomes fine, and the CBTA component can be uniformly adsorbed as compared to the case where the CBTA component is adsorbed by precipitation by simply contacting it with an aqueous solution in which the CBTA component is dispersed.

Carrier foil is foil for supporting ultra-thin copper foil and improving the handling property. As an example of carrier foil, aluminum foil, copper foil, stainless (SUS) foil, the resin film etc. which carried out the metal coating of the surface are mentioned, Preferably it is copper foil. Any of a rolled copper foil and an electrolytic copper foil may be sufficient as copper foil. The thickness of carrier foil is 250 micrometers or less typically, Preferably it is 9 micrometers - 200 micrometers.

The ultra-thin copper foil is not particularly limited as long as it has a well-known configuration employed in the ultra-thin copper foil with a carrier. For example, the ultra-thin copper foil may be formed by a wet film forming method such as an electroless copper plating method and an electrolytic copper plating method, a dry film forming method such as sputtering or chemical vapor deposition, or a combination thereof. The preferable thickness of ultra-thin copper foil is 0.1-7.0 micrometers, More preferably, it is 0.5-5.0 micrometers, More preferably, it is 1.0-3.0 micrometers.

It is preferable that the surface on the opposite side to the peeling layer of ultra-thin copper foil is a roughened surface. That is, it is preferable that the roughening process is performed in one surface of ultra-thin copper foil. By carrying out in this way, adhesiveness with the resin layer at the time of copper clad laminated board or printed wiring board manufacture can be improved. This roughening treatment includes at least two types of plating including a burnt plating process for depositing and adhering fine copper grains onto the ultra-thin copper foil, and a seal plating process for preventing the fine copper grains from falling off. It is preferably carried out according to a known plating method through the process.

You may provide another functional layer between a peeling layer and carrier foil and/or 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, inter-diffusion that may occur between the carrier foil and the ultra-thin copper foil during hot press molding at high temperature or for a long time is suppressed, and the carrier foil is The stability of peel strength can be ensured. The thickness of the auxiliary metal layer is preferably 0.001 to 3 µm.

If desired, the ultra-thin copper foil may be subjected to a rust prevention treatment. It is preferable that a rust prevention process includes the plating process using zinc. The plating treatment using zinc may be either a zinc plating treatment or a zinc alloy plating treatment, and the zinc alloy plating treatment is particularly preferably a zinc-nickel alloy treatment. The zinc-nickel alloy treatment should just be a plating treatment containing at least Ni and Zn, and may further contain other elements, such as Sn, Cr, and Co. As for the Ni/Zn adhesion ratio in zinc-nickel alloy plating, 1.2-10 are preferable in mass ratio, More preferably, it is 2-7, More preferably, it is 2.7-4. Moreover, it is preferable that a rust prevention process further includes a chromate process. It is more preferable that this chromate treatment is performed on the surface of the plating containing zinc after the plating treatment using zinc. By doing in this way, rust prevention property can further be improved. A particularly preferable antirust treatment is a combination of a zinc-nickel alloy plating treatment and a subsequent chromate treatment.

If desired, a silane coupling agent process may be given to the surface of ultra-thin copper foil, and the silane coupling agent layer may be formed. Accordingly, moisture resistance, chemical resistance, adhesion to an adhesive, etc. can be improved. The silane coupling agent layer can be formed by appropriately diluting and applying a silane coupling agent, followed by drying. Examples of the silane coupling agent include an epoxy functional silane coupling agent such as 4-glycidylbutyltrimethoxysilane and γ-glycidoxypropyltrimethoxysilane, or γ-aminopropyltrimethoxysilane, N-β( Aminoethyl) γ-aminopropyltrimethoxysilane, N-3-(4-(3-aminopropoxy)butoxy)propyl-3-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrime Amino functional silane coupling agents such as toxysilane, mercapto functional silane coupling agents such as γ-mercaptopropyltrimethoxysilane, or olefin functional silane coupling agents such as vinyltrimethoxysilane and vinylphenyltrimethoxysilane a ring agent or an acryl-functional silane coupling agent such as γ-methacryloxypropyltrimethoxysilane, an imidazole-functional silane coupling agent such as imidazole silane, or a triazine-functional silane coupling agent such as triazinesilane can be heard

Dongjang laminate

It is preferable that the copper foil with a carrier of this invention is used for preparation of the copper clad laminated board for printed wiring boards. That is, according to the preferable aspect of this invention, the copper clad laminated board obtained using the said copper foil with a carrier is provided. This copper clad laminated board is equipped with the copper foil with a carrier of this invention, and the resin layer provided by closely_contact|adhering to the ultra-thin copper foil of this copper foil with a carrier. The copper foil with a carrier may be provided in the single side|surface of a resin layer, and may be provided in both surfaces. 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 term for a composite material in which a synthetic resin is impregnated into a base material such as a synthetic resin plate, a glass plate, a glass woven fabric, a glass nonwoven fabric, or paper. Preferred 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. Moreover, as an example of insulating resin which comprises a resin sheet, insulating resin, such as an epoxy resin, a polyimide resin, and a polyester resin, is mentioned. Moreover, the filler particle etc. which consist of various inorganic particles, such as a silica and an alumina, from a viewpoint of improving insulation etc. may be contained in a resin layer. Although the thickness of a resin layer is not specifically limited, 1-1000 micrometers is preferable, More preferably, it is 2-400 micrometers, More preferably, it is 3-200 micrometers. The resin layer may be constituted by a plurality of layers. Resin layers, such as a prepreg and/or a resin sheet, may be provided in the ultra-thin copper foil with a carrier via the primer resin layer previously apply|coated to the copper foil surface.

print wiring board

It is preferable that the copper foil with a carrier of this invention is used for preparation of a printed wiring board. That is, according to the preferable aspect of this invention, the printed wiring board obtained using the said copper foil with a carrier is provided. The printed wiring board by this aspect consists of a resin layer and the laminated constitution in which the copper layer was laminated|stacked in this order. In addition, about the resin layer, it is as having mentioned above about a copper clad laminated board. In any case, as for the printed wiring board, a well-known layered structure is employable. Specific examples of the printed wiring board include a single-sided or double-sided printed wiring board in which the ultra-thin copper foil of the present invention is adhered to one or both sides of a prepreg to form a cured laminate, and a single- or double-sided printed wiring board in which these are multilayered. Moreover, as another specific example, the ultra-thin copper foil of this invention is formed on a resin film, The flexible printed wiring board which forms a circuit, COF, TAB tape, etc. are mentioned. As another specific example, after forming a resin-coated copper foil (RCC) in which the above-mentioned resin layer is applied to the ultra-thin copper foil of the present invention, and laminating the resin layer as an insulating adhesive layer on the above-mentioned printed wiring board, the ultra-thin copper foil is applied to the entire wiring layer. Alternatively, a build-up wiring board in which a circuit is formed by a method such as a modified semi-additive (MSAP) method or a subtractive method, or a build-up in which an ultra-thin copper foil is removed and a circuit is formed by a semi-additive (SAP) method Direct build-up-on-wafer etc. which repeat lamination|stacking of copper foil with resin and circuit formation on a wiring board and a semiconductor integrated circuit alternately are mentioned. The copper foil with a carrier of this invention can be used suitably also for the manufacturing method using the coreless buildup method in which an insulating resin layer and a conductor layer are laminated|stacked alternately, without using what is called a core board.

[Example]

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

Examples 1 to 9

Preparation and evaluation of copper foil with a carrier were performed as follows.

(1) Preparation of carrier foil

As carrier foil, the electrolytic copper foil (Mitsui Ginzoku Kogyo Co., Ltd. make, Class-III) which has not performed the roughening process and rust prevention process of 18 micrometers thickness was prepared.

(2) Formation of a release layer

The electrode surface side of the carrier foil subjected to the pickling treatment was placed 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 of the concentrations shown in Table 1 below, at a liquid temperature of 30° C. (Example 1- 4, 7, and 8) or 40 ℃ (Examples 5, 6 and 9) for 30 seconds immersion, the CBTA component was adsorbed to the electrode surface of the carrier foil. In this way, the CBTA layer was formed as an organic peeling layer on the surface of the electrode surface of carrier foil. In addition, Example 7 is a composition corresponding to Example 3 disclosed in patent document 2 (Japanese Patent Laid-Open No. 2003-328178).

[Table 1]

(3) Formation of auxiliary metal layer

The carrier foil with the organic release layer formed thereon was immersed in a solution having a nickel concentration of 20 g/L prepared using nickel sulfate, and under the conditions of a liquid temperature of 45° C., pH 3, and a current density of 5 A/dm 2, an adhesion amount equivalent to a thickness of 0.001 μm Nickel was deposited on the organic release layer. In this way, a nickel layer was formed as an auxiliary metal layer on the organic release layer.

(4) Formation of ultra-thin copper foil

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

<Composition of solution>

-Copper Concentration: 65g/L

-Sulfuric acid concentration: 150g/L

(5) Harmonization processing

The surface of the ultra-thin copper foil formed in this way was roughened. This roughening process is comprised with the burnt plating process of depositing and adhering fine copper grains on ultra-thin copper foil, and the seal plating process for preventing drop-off|omission of this fine copper grain. At the burnt plating process, the roughening process was performed by the liquid temperature of 25 degreeC and the current density of 10 A/dm<2> using the acidic copper sulfate solution containing 18 g/L of copper and 100 g/L of sulfuric acid. In the subsequent seal plating process, the copper solution containing 65 g/L of copper and 150 g/L of sulfuric acid was used, and electrodeposition was performed on the smooth plating conditions of 45 degreeC liquid temperature and 15 A/dm<2> of current density.

(6) Anti-rust treatment

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

(7) Silane coupling agent treatment

The copper foil to which the said rust prevention process was given was washed with water, the silane coupling agent process was performed immediately after that, and the silane coupling agent was made to adsorb|suck on the rust prevention process layer of a roughening process surface. This silane coupling agent process used pure water as a solvent, 3-aminopropyl trimethoxysilane concentration used the solution of 3 g/L, Blowing this solution to the roughening process surface with a shower ring, and adsorption-processing performed it. After adsorption|suction of a silane coupling agent, water|moisture content was finally evaporated with the electric heater, and the copper foil with a carrier was obtained.

(8) Evaluation of copper foil with carrier

The following evaluation was performed about the obtained copper foil with a carrier.

<Analysis of exfoliation layer>

The carrier foil was peeled from the copper foil with a carrier. The peeled carrier foil and ultra-thin copper foil were immersed in 1 mol/L hydrochloric acid at 40 degreeC for 60 minutes, and CBTA was extracted. In that case, by masking the surface on the opposite side to the peeling layer of carrier foil and ultra-thin copper foil, it was made that only the surface which is in contact with the peeling layer adheres to extraction of CBTA. The thus-obtained CBTA-containing extract was analyzed by high performance liquid chromatography (manufactured by Shimadzu Corporation, HPLC LC10 series) to measure the concentrations of 5CBTA and 4CBTA, and the amount of 5CBTA adhered (mg/m2), 4CBTA The adhesion amount (mg/m 2 ), the total adhesion amount of CBTA (mg/m 2 ), and the 5CBTA/4CBTA ratio were calculated. The results are as shown in Table 2.

<Measurement of Peel Strength>

First, the measurement of the peeling strength of the state in copper foil with a carrier was performed as follows. The double-sided tape was affixed on the ultra-thin copper foil side of the copper foil with a carrier, and it affixed and fixed it to the board|substrate, and the measurement sample was obtained. With respect to the measurement sample, in accordance with JIS C 6481-1996, measured the peel strength RS ₀ (gf / ㎝) in the state it was in when peeling off the carrier foil. At this time, the measurement width was 50 mm, and the measurement length was 20 mm.

Next, the peel strength after 1 time or 2 times of hot pressing was measured as follows. As a resin base material, the 100-micrometer-thick prepreg (Mitsubishi Gas Chemical Co., Ltd. make, GHPL830NX-A) was prepared. Copper foil with a carrier is laminated on this resin base material so that the ultra-thin copper foil side is in contact with the resin base material, and hot press forming is performed once or twice at a pressure of 2.5 MPa and a temperature of 230 ° C. for 60 minutes. A copper clad laminate sample was obtained. With respect to the copper clad laminate sample, in accordance with JIS C 6481-1996, the carrier foil was peeled from the ultra-thin copper foil laminated on the surface of the resin substrate, and peel strength RS ₁ (after one hot press) and peel strength RS ₂ (hot press twice) after) (gf/cm) was measured. At this time, the measurement width was 50 mm, and the measurement length was 20 mm. The ratio ((RS ₂ -RS ₀ )/RS _{0 ) of the peel strength RS 2} after two times of hot pressing to the peel strength RS ₀ in the state before hot pressing was multiplied by 100 to calculate the peel strength increase rate (%). The results are as shown in Table 2.

[Table 2]

* indicates a comparative example.

Claims (6)

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 comprises 5-carboxybenzotriazole (5CBTA) and 4-carboxybenzotriazole (4CBTA), and the amount of 5-carboxybenzotriazole attached to the release layer is 4-carboxybenzotriazole. 5CBTA/4CBTA ratio, which is the ratio to the amount of adhesion of the sol, is 3.5 to 30,
Copper foil with a carrier in which the said peeling layer contains 5-carboxybenzotriazole (5CBTA) and 4-carboxybenzotriazole (4CBTA) in the adhesion amount of 3 mg/m<2> or more and 80 mg/m<2> or less in total. delete delete delete According to claim 1,
Copper foil with a carrier further provided with an auxiliary metal layer between the said peeling layer and the said carrier foil, or between the said peeling layer and the said ultra-thin copper foil, or both. A copper clad laminated board provided with the copper foil with a carrier of Claim 1 or 5.