Copper foil with carrier foil and copper foil laminate using the same

Abstract

The present invention relates to a carrier foil-attached copper foil having good peel strength under high-temperature pressing conditions.The present invention provides an ultra-thin copper foil with a carrier foil, comprising a carrier foil, a release layer on the carrier foil, a heat-resistant layer on the release layer, and an ultra-thin copper foil on the heat-resistant layer, wherein a buffer layer made of a Ni alloy is sandwiched between the release layer and the heat-resistant layer.

Description

[Technical Field]

[0001] The present invention relates to a carrier foil-equipped copper foil and a copper foil laminate produced using the same, and more particularly to a carrier foil-equipped copper foil having good peel strength under high-temperature pressing conditions and a copper foil laminate using the same. [Background technology]

[0002] Conventional carrier foil-attached copper foils for semiconductor substrates usually have a laminated structure including a release layer, a diffusion barrier layer, and an ultra-thin copper foil formed on a carrier foil.

[0003] Conventionally, a press process was performed at 220 to 240°C to bond a carrier foil-attached copper foil to a resin substrate. Recently, however, by using a highly heat-resistant resin substrate, the carrier foil-attached copper foil is press-molded at a high temperature of 350°C or higher. However, in this case, there are problems such as the occurrence of blistering of the copper foil in the form of a crater between the carrier foil and the ultra-thin copper foil, or the inability of the diffusion barrier layer to withstand the temperature, resulting in an increase in the peel strength between the carrier foil and the ultra-thin copper foil. Summary of the Invention [Problem to be solved by the invention]

[0004] The inventors of the present invention have discovered that if the amount of nickel in the diffusion barrier layer is insufficient or excessive during press molding at high temperatures of 350°C or higher, the stability of the peel strength between the carrier foil and the ultrathin copper foil decreases or crater-shaped blistering of the copper foil occurs. Therefore, an object of the present invention is to provide a copper foil with a carrier foil having a laminate structure that suppresses the blistering of the copper foil during high-temperature press molding.

[0005] On the other hand, the inventors of the present invention have discovered that when using a copper foil with a carrier foil having the above-mentioned laminated structure to suppress the copper foil blister phenomenon, if the peel strength is 10 gf / cm or less, the carrier foil and the copper foil may be separated too easily during the production of a copper foil laminate, which may cause defects, and if the peel strength is 30 gf / cm or more, it may be difficult to separate the carrier foil during the production of a copper foil laminate, which may cause defects such as bending of the substrate.

[0006] Therefore, an object of the present invention is to propose a copper foil laminate structure that maintains the peel strength between the carrier foil and the ultrathin copper foil of a carrier foil-attached foil at 10 to 30 gf / cm.

[0007] Another object of the present invention is to provide a copper foil laminate produced using the above-mentioned carrier foil-attached copper foil. [Means for solving the problem]

[0008] In order to achieve the above technical objectives, the present invention provides a carrier foil-attached copper foil comprising a carrier foil, a release layer on the carrier foil, a heat-resistant layer on the release layer, and an ultra-thin copper foil on the heat-resistant layer, characterized in that a buffer layer made of a Ni alloy is sandwiched between the release layer and the heat-resistant layer.

[0009] In the present invention, the buffer layer may include a Cu—Ni alloy, and may be plated using a plating solution having a Cu concentration and a Ni concentration in the range of 1:5 to 1:20.

[0010] In the present invention, the thickness of the buffer layer is preferably 20 to 50 nm.

[0011] In the present invention, the thickness of the heat-resistant layer is preferably 5 to 50 nm.

[0012] In the present invention, the release layer may be an organic release layer or an inorganic release layer.

[0013] In the present invention, the heat-resistant layer may be a Ni-plated layer, or may be plated with a plating solution containing Ni and P.

[0014] The carrier foil-attached copper foil of the present invention preferably has a 90° peel strength of 10 to 30 gf / cm after press working at 400° C. for 60 minutes.

[0015] In order to achieve the above-mentioned other technical object, the present invention also provides a copper foil laminate including a copper foil laminated on a resin substrate, wherein the copper foil is produced by bonding the above-mentioned carrier foil-attached copper foil to the resin substrate.

[0016] In the present invention, the resin substrate may be one selected from the group consisting of polyimide, fluororesin, and LCP. [Effects of the Invention]

[0017] According to the present invention, it is possible to provide a carrier foil-attached copper foil having a laminated structure that suppresses the blister phenomenon of the copper foil during high-temperature press molding at 350°C or higher.

[0018] Furthermore, according to the present invention, even when a copper foil with a carrier foil having a laminated structure is used to suppress the blister phenomenon of the copper foil, it is possible to maintain the peel strength between the carrier foil and the ultrathin copper foil at 10 to 30 gf / cm. [Brief explanation of the drawings]

[0019] The accompanying drawings, which are included as part of the detailed description to aid in understanding the present invention, provide examples of the present invention and, together with the detailed description, explain the technical concepts of the present invention.

[0020] [Figure 1] 1 is a diagram illustrating a carrier foil-equipped copper foil (100) according to an embodiment of the present invention.

[0021] [Figure 2A]1 is an optical microscope photograph of the peeled surface after the carrier foil is peeled off from a sample of an example that has been press-processed at 350° C. [Figure 2B] 1 is an optical microscope photograph of the peeled surface after the carrier foil is peeled off from a sample of a comparative example that has been press-processed at 350° C.

[0022] [Figure 3A] 1 is an AES analysis graph of a carrier foil-attached copper foil sample manufactured in an example. [Figure 3B] 1 is an AES analysis graph of a carrier foil-attached copper foil sample manufactured in a comparative example.

[0023] [Figure 4] 1 is a graph showing the results of measuring peel strength after pressing at 400° C. for samples of examples of the present invention and comparative examples.

[0024] [Figure 5] FIG. 1 is a diagram showing a press condition profile when measuring peel strength. DETAILED DESCRIPTION OF THE INVENTION

[0025] In the drawings, identical components are denoted by the same reference numerals whenever possible. Detailed descriptions of already known functions and / or configurations are omitted. The following disclosure focuses on the parts necessary for understanding the operation of various embodiments, and descriptions of elements that may obscure the gist of the description are omitted. Some components in the drawings may be exaggerated, omitted, or illustrated schematically. The size of each component does not necessarily reflect the actual size. Therefore, the content described herein is not limited by the relative size or spacing of the components depicted in each drawing.

[0026] When describing embodiments of the present invention, if a detailed description of known technologies related to the present invention is deemed to obscure the gist of the present invention, such detailed description will be omitted. Terms used in the detailed description of the present invention are intended solely to describe embodiments of the present invention and are in no way limiting. Unless otherwise specified, singular expressions may include plural meanings. In this description, terms such as "comprise" or "comprises" are intended to refer to certain features, numbers, steps, operations, elements, parts thereof, or combinations thereof, and should not be interpreted as excluding the presence or possibility of one or more other features, numbers, steps, operations, elements, parts thereof, or combinations other than those described.

[0027] Furthermore, terms such as first and second may be used to describe various components, but these components are not limited by these terms, and these terms are only used to distinguish one component from another.

[0028] In the present specification, lamination means bonding at least two layers together. For example, lamination of a first layer and a second layer includes not only direct contact between the first and second layers, but also bonding by sandwiching a third layer between the first and second layers.

[0029] FIG. 1 is a diagram illustrating a carrier foil-equipped copper foil 100 according to an embodiment of the present invention.

[0030] Referring to FIG. 1, the carrier foil-attached copper foil according to one embodiment of the present invention may have a structure in which a carrier foil 110, a release layer 120, a buffer layer 130, a heat-resistant layer 140, and an ultra-thin copper foil 150 are laminated.

[0031] In the present invention, the carrier foil 110 serves as a support (carrier) until the ultrathin copper foil is bonded to the insulating substrate. The carrier foil may be an aluminum foil, a stainless steel foil, a titanium foil, a copper foil, or a copper alloy foil. For example, an electrolytic copper foil, an electrolytic copper alloy foil, a rolled copper foil, or a rolled copper alloy foil may be used. Preferably, the carrier foil may be an electrolytic copper foil, and the upper surface (100B) of the carrier foil may be either a glossy surface or a matte surface. Furthermore, in the present invention, a roughened layer may be formed on the lower surface (100A) of the carrier foil.

[0032] The carrier foil may have a thickness of 1 mm or less. For example, the thickness of the carrier foil may be 10 to 100 μm. For example, the thickness of the carrier foil may be 12 to 18 μm. If the thickness of the carrier foil is less than 10 μm, it may be difficult for the carrier foil to function as a carrier. If the thickness of the carrier foil is more than 1 mm, there is no problem in functioning as a carrier, but when continuous plating is performed to form a release layer, an ultra-thin copper foil, etc., the foil tension in the continuous plating line must be increased, which may require large-scale equipment.

[0033] In the present invention, the roughness (R z ) may be 1.7 μm or less, 1.5 μm or less, or 1.3 μm or less. z ) may be 0.7 μm or more, 0.9 μm or more, or 1.1 μm or more.

[0034] The release layer 120 in the carrier foil-attached copper foil is a layer for improving the peelability when peeling the ultra-thin copper foil from the carrier foil, and is introduced to allow the carrier foil to be peeled cleanly and easily. The release layer is removed together with the carrier foil.

[0035] In the present invention, the release layer 120 may include a metal or metal alloy having release properties. The release metal may include molybdenum or tungsten. The release layer 130 may also include a plating catalyst. For example, the release layer 130 may include at least one metal selected from the group consisting of Fe, Co, and Ni.

[0036] The release layer may be an organic release layer having releasability. For example, the release layer may contain at least one organic material selected from the group consisting of benzotriazol (BTA)-based materials.

[0037] In the present invention, the heat-resistant layer 140 may contain one or more elements selected from the group consisting of Ni, Co, Fe, Cr, Mo, W, Al, and P. For example, the heat-resistant layer may be a single metal layer, an alloy layer of two or more metals, or a layer of one or more metal oxides.

[0038] For example, plating to form a single metal layer may be nickel plating, cobalt plating, iron plating, aluminum plating, etc. Plating to form a binary alloy layer may be nickel-cobalt plating, nickel-iron plating, nickel-chromium plating, nickel-molybdenum plating, nickel-tungsten plating, nickel-copper plating, nickel-phosphorus plating, cobalt-iron plating, cobalt-chromium plating, cobalt-molybdenum plating, cobalt-tungsten plating, cobalt-copper plating, cobalt-phosphorus plating, etc. Plating that forms a ternary alloy layer includes nickel-cobalt-iron plating, nickel-cobalt-chromium plating, nickel-cobalt-molybdenum plating, nickel-cobalt-tungsten plating, nickel-cobalt-copper plating, nickel-cobalt-phosphorus plating, nickel-iron-chromium plating, nickel-iron-molybdenum plating, nickel-iron-tungsten plating, nickel-iron-copper plating, nickel-iron-phosphorus plating, nickel-chromium-molybdenum plating, nickel-chromium-tungsten plating, nickel-chromium-copper plating, nickel-chromium-phosphorus plating, nickel-molybdenum-tungsten plating, nickel-molybdenum-copper plating, nickel-molybdenum Cobalt-chromium-phosphorus plating, nickel-tungsten-copper plating, nickel-tungsten-phosphorus plating, nickel-copper-phosphorus plating, cobalt-iron-chromium plating, cobalt-iron-molybdenum plating, cobalt-iron-tungsten plating, cobalt-iron-copper plating, cobalt-iron-phosphorus plating, cobalt-chromium-molybdenum plating, cobalt-chromium-tungsten plating, cobalt-chromium-copper plating, cobalt-chromium-phosphorus plating, cobalt-molybdenum-phosphorus plating, cobalt-tungsten-copper plating, cobalt-tungsten-phosphorus plating, cobalt-copper-phosphorus plating, and the like may be used.

[0039] Preferably, in the present invention, the heat-resistant layer 140 may be a Ni-P plating layer containing Ni and P.

[0040] The heat-resistant layer 140 prevents copper from diffusing into the release layer when the carrier foil-attached copper foil is pressed against an insulating substrate at high temperatures. The diffusion of copper into the release layer can form a metallic bond between the carrier foil and the ultra-thin copper foil, making it difficult to peel the carrier foil due to the strong bonding force between them. The heat-resistant layer 120 can prevent such a reaction.

[0041] In the present invention, the metal deposition amount of the heat-resistant layer 140 is 50 μg / dm 2 More than 60μg / dm 2 or more, or 70 μg / dm 2 or more, and the metal deposition amount is 120 μg / dm 2 Below, 110μg / dm 2 or less than 100 μg / dm 2 In the present invention, the metal coverage of the heat-resistant layer may be a Ni coverage.

[0042] On the other hand, if the nickel content of the heat-resistant layer 140 is low, the peel strength between the carrier foil and the ultra-thin copper foil increases, and if the nickel content is high, a crater-shaped blisters phenomenon occurs in the copper foil. In the present invention, this problem is solved by laminating a buffer layer having a different Ni content from the heat-resistant layer.

[0043] In the present invention, the thickness of the heat-resistant layer 140 may be 5 nm or more, 7 nm or more, or 10 nm or more, and is preferably 50 nm or less, 30 nm or less, or 20 nm or less.

[0044] The copper foil with carrier foil of the present invention includes a buffer layer 130 between the release layer 120 and the heat-resistant layer 140. In the present invention, the buffer layer 130 protects the release layer under high-temperature pressing conditions of 350°C or higher, suppresses copper diffusion between the carrier foil and the ultrathin copper foil, prevents blistering, and ensures stable peel strength.

[0045] In the present invention, the thickness of the buffer layer 130 may be 20 nm or more, or 30 nm or more. The thickness of the buffer layer 130 may also be 60 nm or less, or 50 nm or less. For example, the thickness of the buffer layer 130 may be 20 to 50 nm. If the buffer layer is 20 nm or less, it will not function properly and blistering will occur. If the buffer layer is 50 nm or more, peel strength will be significantly reduced, and lifting between the carrier foil and the ultrathin copper foil may occur.

[0046] In the present invention, the thickness ratio of the heat-resistant layer to the buffer layer may be 1:1.5 to 1:5, and preferably, the thickness ratio of the heat-resistant layer to the buffer layer is 1.2 to 1.3.

[0047] In the present invention, the buffer layer 130 is preferably a Ni alloy layer, and more preferably a Ni—Cu alloy layer.

[0048] In the present invention, the Ni deposition amount of the buffer layer 130 is 50 μg / dm 2 More than 60μg / dm 2 More than 70μg / dm 2 More than 80μg / dm 2 More than 90μg / dm 2 or more, or 100 μg / dm 2 The Ni deposition amount of the buffer layer 130 may be 300 μg / dm 2 Below, 250μg / dm 2 Below, 200μg / dm 2 , or 150 μg / dm 2 It is preferable that:

[0049] In the present invention, the buffer layer 130 is preferably formed by electroplating. In the present invention, the Ni-Cu alloy buffer layer may be manufactured from a plating solution having a high Ni content ratio. For example, the buffer layer may be electroplated from a plating solution having a Cu concentration to Ni concentration ratio of 1:20 to 1:5, preferably 1:15 to 1:7.

[0050] In the present invention, the ultra-thin copper foil 150 may have a thickness of 12 μm or less. Preferably, the ultra-thin copper foil may have a thickness of 1.5 to 5 μm. Also, in the present invention, the ultra-thin copper foil preferably has a surface roughness (Rz) of 0.5 to 1.5 μm.

[0051] Ultra-thin copper foils may have a roughened side and a non-roughened side depending on the application. The roughened side may be formed by a nodulation process, and the non-roughened side may be formed by adding a brightener and a suppressor during the formation of the copper foil.

[0052] In the present invention, the surface of the ultrathin copper foil may be further treated by, for example, heat and chemical resistance treatment, chromate treatment, silane coupling treatment, or a combination thereof, and the type of surface treatment may be appropriately selected depending on the subsequent process.

[0053] The heat and chemical resistance treatment can be performed by forming a thin film of any one of metals such as nickel, tin, zinc, chromium, molybdenum, and cobalt, or an alloy thereof, on the metal foil by sputtering, electroplating, or electroless plating, with electroplating being preferred from the viewpoint of cost.

[0054] For the chromate treatment, an aqueous solution containing hexavalent to trivalent chromium ions can be used. The chromate treatment can be a simple immersion treatment, but is preferably carried out by cathodic treatment. For example, cathodic treatment can be carried out using sodium dichromate 0.1 to 70 g / L, pH 1 to 13, bath temperature 15 to 60°C, current density 0.1 to 5 A / dm 2 It is preferable to carry out the electrolysis for a period of 0.1 to 100 seconds. It is also preferable to carry out the chromate treatment on top of the rust prevention treatment, which can further improve the moisture resistance and heat resistance.

[0055] Examples of silane coupling agents used in the silane coupling treatment include one or more substances or mixtures selected from the group consisting of epoxy-functional silanes such as 3-glycidoxypropyltrimethoxysilane and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, amino-functional silanes, olefin-functional silanes, acryl-functional silanes, methacryl-functional silanes, and mercapto-functional silanes. For example, the silane coupling agent is dissolved in a solvent such as water at a concentration of 0.1 to 15 g / L and applied to the metal foil at room temperature to 70°C, or the silane coupling agent is adsorbed by electrodeposition. After the silane coupling treatment, a stable bond may be formed by heating, ultraviolet irradiation, or the like. Heating may be performed at a temperature of 100 to 200°C for 2 to 60 seconds.

[0056] The above describes an example of a structure in which the carrier foil, release layer, buffer layer, heat-resistant layer, and ultra-thin copper foil constituting the carrier foil-coated copper foil are laminated in contact with each other in this order, but if necessary, other layers may be added between each layer constituting the laminated structure.

[0057] For example, a diffusion barrier layer may be added between the carrier foil and the release layer. The diffusion of copper from the carrier foil to the release layer may form a metal bond, and the strong bonding force between them may make it difficult to peel off the carrier foil. Therefore, a diffusion barrier layer may be further introduced to take such a reaction into consideration.

[0058] Meanwhile, in the present invention, the carrier foil-attached copper foil may be bonded to a resin having low dielectric properties, such as polyimide, fluororesin, LCP resin, etc., to produce a copper foil laminate, and such a copper foil laminate may be used to produce a printed wiring board.

[0059] The present invention will be described in more detail below with reference to examples, which are presented as preferred examples of the present invention and are not intended to limit the present invention in any way. [Example]

[0060] Example 1

[0061] A copper foil with a carrier foil was produced by the following method.

[0062] A. Carrier foil

[0063] An electrolytic copper foil with a surface roughness of 1.2 μm and a thickness of 18 μm was used.

[0064] B. Release layer

[0065] The organic release layer was formed under the following conditions.

[0066] - Carboxybenzotriazole concentration: 1-5g / L, copper concentration: 5-15g / L, H2SO4 concentration: 150g / L

[0067] - Temperature: 40℃, Soaking time: 25 seconds

[0068] C. Buffer layer

[0069] A buffer layer was formed on the carrier foil using the following plating method and conditions. The thickness of the formed buffer layer was 35 nm.

[0070] - Copper concentration: 5-10g / L, Nickel concentration: 50-100g / L, Boric acid concentration: 20-50g / L

[0071] - Temperature: 30℃, Current density: 2.0A / dm 2 , Plating time: 2.5 seconds

[0072] D. Heat resistant layer

[0073] The heat-resistant layer was formed using the following plating method and conditions. The Ni deposition amount of the formed heat-resistant layer was 90 μg / dm 2 It was.

[0074] - Ni concentration: 15~25g / L, P concentration: 10~20g / L

[0075] - pH: 4.0, temperature: 30℃, current density: 0.5A / dm 2 , Plating time: 6 seconds

[0076] E. Ultra-thin copper foil

[0077] Ultra-thin copper foil was formed using the following plating method and conditions. The plating thickness was 2 μm.

[0078] - CuSO4-5H2O:250g / L, H2SO4:100g / L

[0079] - Temperature: 35℃, Current density: 20A / dm 2 , Plating time: 30 seconds

[0080] Next, the surface of the ultra-thin copper foil was further subjected to a heat-resistant and chemical-resistant treatment, a chromate treatment, and a silane coupling treatment.

[0081] <Example 2>

[0082] Except for forming the buffer layer to a thickness of 25 nm, a carrier foil-attached copper foil was produced in the same manner as in Example 1. The buffer layer plating conditions were as follows.

[0083] - Copper concentration: 5-10g / L, Nickel concentration: 50-100g / L, Boric acid concentration: 20-50g / L

[0084] - Temperature: 30℃, Current density: 2.0A / dm 2 , Plating time: 1.8 seconds

[0085] Example 3

[0086] Except for forming the buffer layer to a thickness of 45 nm, a carrier foil-attached copper foil was produced in the same manner as in Example 1. The buffer layer plating conditions were as follows.

[0087] - Copper concentration: 5-10g / L, Nickel concentration: 50-100g / L, Boric acid concentration: 20-50g / L

[0088] - Temperature: 30℃, Current density: 2.0A / dm 2 , Plating time: 3.3 seconds

[0089] Example 4

[0090] A carrier foil-attached copper foil was produced in the same manner as in Example 1, except that an inorganic release layer was formed as the release layer. The inorganic release layer was formed by Mo-Ni-Fe plating. The coating weight of the formed release layer was 0.9 mg / dm 2 The composition of the release layer was 60.31 wt % Mo, 31.6 wt % Ni, and 8.09 wt % Fe.

[0091] - Mo concentration: 10-30g / L, Ni concentration: 3-10g / L, Fe concentration: 1-5g / L, Sodium citrate: 100-200g / L

[0092] - pH: 10.2 (ammonia water 30 ml / L added), temperature: 30°C, current density: 8 A / dm 2 , Plating time: 6 seconds

[0093] <Comparative Example 1>

[0094] A copper foil with a carrier foil was produced in the same manner as in Example 1, except that the buffer layer was omitted.

[0095] <Comparative Example 2>

[0096] A copper foil with a carrier foil was produced by the following method.

[0097] A. Carrier foil

[0098] The carrier foil used was an electrolytic copper foil with a surface roughness of 1.2 μm and a thickness of 18 μm.

[0099] B. Diffusion prevention layer

[0100] A diffusion barrier layer was formed on the carrier foil by Ni plating. The plating temperature and plating conditions were as follows: The coating weight of the formed diffusion barrier layer was 352 μg / dm 2 It was.

[0101] - Ni concentration: 15~25g / L, P concentration: 10~20g / L, pH: 4.0

[0102] - Temperature: 30℃, Current density: 1.5A / dm 2 , Plating time: 2 seconds

[0103] C. Release layer formation

[0104] The peeling layer was formed by Mo-Ni-Fe plating. The adhesion weight of the peeling layer was 0.9 mg / dm 2 The composition of the release layer was 60.31 wt % Mo, 31.6 wt % Ni, and 8.09 wt % Fe.

[0105] - Mo concentration: 10-30g / L, Ni concentration: 3-10g / L, Fe concentration: 1-5g / L, Sodium citrate: 100-200g / L

[0106] - pH: 10.2 (ammonia water 30 ml / L added), temperature: 30°C, current density: 8 A / dm 2 , Plating time: 6 seconds

[0107] D. Heat-resistant layer formation

[0108] The heat-resistant layer was formed using the following plating method and conditions. The Ni deposition amount of the formed heat-resistant layer was 33 μg / dm 2 It was.

[0109] - Ni concentration: 15~25g / L, P concentration: 10~20g / L

[0110] - pH: 4.0, temperature: 30℃, current density: 0.5A / dm 2 , Plating time: 2 seconds

[0111] E. Ultra-thin copper foil formation

[0112] Ultra-thin copper foil was formed using the following plating method and conditions. The plating thickness was 2 μm.

[0113] - CuSO4-5H2O:250g / L, H2SO4:100g / L

[0114] - Temperature: 35℃, Current density: 20A / dm 2 , Plating time: 30 seconds

[0115] Next, the surface of the ultra-thin copper foil was further subjected to a heat-resistant and chemical-resistant treatment, a chromate treatment, and a silane coupling treatment.

[0116] <Comparative Example 3>

[0117] A copper foil with a carrier foil was produced in the same manner as in Example 1, except that the thickness of the buffer layer (blister prevention layer) was set to 15 nm.

[0118] The plating conditions for the buffer layer were as follows:

[0119] - Copper concentration: 5-10g / L, Ni concentration: 50-100g / L, Boric acid concentration: 20-50g / L

[0120] - Temperature: 30℃, Current density: 2.0A / dm 2 , Plating time: 1.5 seconds

[0121] <Comparative Example 4>

[0122] A copper foil with a carrier foil was produced in the same manner as in Example 1, except that the thickness of the buffer layer (blister prevention layer) was set to 70 nm.

[0123] - Copper concentration: 5-10g / L, Ni concentration: 50-100g / L, Boric acid concentration: 20-50g / L

[0124] - Temperature: 30℃, Current density: 2.0A / dm 2 , Plating time: 1.5 seconds

[0125] <Characteristics evaluation>

[0126] The properties of the test pieces of the carrier foil-attached copper foils produced in the Examples and Comparative Examples were evaluated by the following methods.

[0127] A. Blistering characteristics evaluation

[0128] After pressing at each temperature (220°C, 350°C, 400°C), the surface after peeling off the carrier foil was visually observed. If even one crater-shaped blister was found, it was judged to be defective.

[0129] B.AES analysis

[0130] The analysis was performed using PHI 700™ (Scanning Auger Nanoprobe) under the following analytical conditions:

[0131] - Beam size (10keV 10nA): 20nm

[0132] - Analysis area (μm or point): 10μmx10μm,Area

[0133] - Tilt(°) / Stage Normal(°):30° / 60°

[0134] - Analyzer:CMA(Cylindrical Mirror Analyzer)

[0135] C. Optical Microscopy Analysis

[0136] Observation was performed using a HIROX HK7700 at 200x magnification.

[0137] D. Peel strength evaluation

[0138] Teflon resin (50 μm thick) from Mirae EMC was prepared, and a copper foil test piece with a width of 30 mm was prepared. The copper foil was then pressed onto the resin at temperatures of 220°C, 350°C, and 400°C to prepare the sample (pressing conditions: pressure of 4.9 MPa, maintained for 60 minutes). The pressing condition profile is shown in Figure 5.

[0139] The peel strength of the prepared sample was measured by the 90° peel method in accordance with JIS C64718.1.

[0140] Table 1 below summarizes the results of the blister properties and peel strength.

[0141] [Table 1]

[0142] In the case of Example 1, no blistering occurred even when pressed at 350°C and 400°C, and the peel strength between the carrier foil and the ultra-thin copper foil was confirmed to be very good, at 15 gf / cm at 220°C, 16 gf / cm at 350°C, and 21 gf / cm at 400°C. In the case of Example 2, no blistering occurred after pressing at 350°C and 400°C, and the peel strength between the carrier foil and the ultra-thin copper foil was confirmed to be very good, at 14 gf / cm at 220°C, 18 gf / cm at 350°C, and 26 gf / cm at 400°C.

[0143] In the case of Example 3, no blistering occurred after pressing at 350°C and 400°C, and the peel strength between the carrier foil and the ultra-thin copper foil was confirmed to be very good, at 12 gf / cm at 220°C, 15 gf / cm at 350°C, and 18 gf / cm at 400°C.

[0144] In the case of Example 4, no blistering occurred after pressing at 350°C and 400°C, and the peel strength between the carrier foil and the ultra-thin copper foil was confirmed to be very good, at 14 gf / cm at 220°C, 14 gf / cm at 350°C, and 28 gf / cm at 400°C.

[0145] In the case of Comparative Example 1, no blistering occurred after pressing at 220°C, and the peel strength between the carrier foil and the ultrathin copper foil was a good 21 gf / cm at 220°C. However, blistering occurred at 350°C, and the peel strength was 87 gf / cm, making it difficult to separate the carrier foil from the ultrathin foil. Furthermore, blistering occurred at 400°C, and the carrier foil and the ultrathin foil could not be separated.

[0146] In the case of Comparative Example 2, no blistering occurred after pressing at 220°C, and the peel strength between the carrier foil and the ultrathin copper foil was a good 18 gf / cm at 220°C. However, blistering occurred at 350°C, and the peel strength was 79 gf / cm, making it difficult to separate the carrier foil from the ultrathin foil. Furthermore, blistering occurred at 400°C, and the carrier foil and the ultrathin foil could not be separated.

[0147] In the case of Comparative Example 3, no blistering occurred after pressing at 220°C, and the peel strength between the carrier foil and the ultrathin copper foil was a good 17 gf / cm at 220°C. However, at 350°C, the peel strength was a good 28 gf / cm, but blistering occurred. Furthermore, at 400°C, in addition to the blistering, the peel strength between the carrier foil and the ultrathin was 84 gf / cm, making it difficult to separate the carrier foil and the ultrathin.

[0148] In the case of Comparative Example 4, no swelling occurred after pressing at 220°C, 350°C, or 400°C, but the peel strength between the carrier foil and the ultra-thin copper foil was 4 gf / cm at 220°C, 6 gf / cm at 350°C, and 7 gf / cm at 400°C, which were significantly low values.

[0149] 2A and 2B are optical microscope photographs of the peeled surfaces of the ultrathin copper foil side of the samples of Example 1 and Comparative Example 1, respectively, after pressing at 350° C. and peeling off the carrier foil.

[0150] Referring to the figure, it can be seen that the peeled surface was clean in Example 1, whereas craters were formed on the peeled surface in Comparative Example 1. This is due to the swelling phenomenon near the peeled layer during pressing.

[0151] 3A and 3B are AES analysis graphs of the carrier foil-attached copper foil samples manufactured in Example 1 and Comparative Example 1, respectively.

[0152] Referring to the same figure, in Example 1, peaks indicating Cu peaks and Ni peaks that are considered to be due to substances contained in the buffer layer can be confirmed compared to Comparative Example 1.

[0153] FIG. 4 is a graph plotting the results of peel strength measurements after pressing at 400° C. for samples of the examples of the present invention and the comparative examples.

[0154] Referring to FIG. 4, it can be seen that Examples 1 to 4 fall within a stable peel strength range of 10 to 30 kg / cm.

[0155] Although the present invention has been described above using specific details such as specific components and limited embodiments and drawings, these are provided merely to facilitate a more comprehensive understanding of the present invention, and the present invention is not limited to the above embodiments. Those skilled in the art will appreciate that various modifications and variations may be made without departing from the essential characteristics of the present invention. Therefore, the concept of the present invention should not be limited to the described embodiments, and the scope of the appended claims and technical concepts equivalent to or modified from the scope of the claims should all be construed as being within the scope of the present invention. [Industrial Applicability]

[0156] The present invention can be used for copper foils, copper foils with carrier foils, and copper foil laminates.

Claims

1. A carrier foil-attached copper foil comprising a carrier foil, a release layer on the carrier foil, a heat-resistant layer on the release layer, and an ultra-thin copper foil on the heat-resistant layer, A carrier foil-attached copper foil characterized in that a buffer layer made of a Ni alloy is sandwiched between the release layer and the heat-resistant layer.

2. The copper foil with carrier foil according to claim 1, wherein the buffer layer contains a Cu-Ni alloy.

3. 3. The copper foil with carrier foil according to claim 2, wherein the buffer layer is plated with a plating solution having a Cu concentration and a Ni concentration of 1:5 to 1:

20.

4. The copper foil with carrier foil according to claim 1, wherein the thickness of the buffer layer is 20 to 50 nm.

5. The copper foil with carrier foil according to claim 1, wherein the heat-resistant layer has a thickness of 5 to 50 nm.

6. The copper foil with carrier foil according to claim 1 , wherein the release layer is an organic release layer.

7. The copper foil with carrier foil according to claim 1 , wherein the release layer is an inorganic release layer.

8. The copper foil with carrier foil according to claim 1, wherein the heat-resistant layer is a Ni-plated layer.

9. The copper foil with a carrier foil according to claim 8, wherein the heat-resistant layer is plated with a plating solution containing Ni and P.

10. 9. The copper foil with a carrier foil according to claim 8, wherein the 90° peel strength after press working at 400° C. for 60 minutes is 10 to 30 gf / cm.

11. A copper foil laminate including a copper foil laminated on a resin substrate, A copper foil laminate produced by bonding the carrier foil-attached copper foil according to claim 1 to the resin substrate.

12. The copper foil laminate according to claim 11, wherein the resin substrate is one selected from the group consisting of polyimide, fluororesin, and LCP.

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