Metal foil with carrier

Abstract

Provided is a metal foil with a carrier, said metal foil making it possible to improve circuit formation properties by suppressing the number of foreign particles on a metal layer surface and to maintain consistent separation properties even after being heated for a long time at a high temperature of 240°C or more (for example, 260°C). This metal foil with a carrier comprises: a carrier; a separation functional layer provided on the carrier and containing a metal oxynitride; and a metal layer provided on the separation functional layer.

Description

[Technical Field]

[0001] The present invention relates to a metal foil with a carrier. [Background technology]

[0002] In recent years, multilayer printed wiring boards have become widespread in order to increase the packaging density and reduce the size of printed wiring boards. Such multilayer printed wiring boards are used in many portable electronic devices for the purpose of reducing weight and size. However, there is a demand for further reduction in the thickness of the interlayer insulating layer and further weight reduction as a wiring board.

[0003] To meet these demands, a coreless buildup method has been adopted for manufacturing multilayer printed wiring boards. The coreless buildup method is a method of alternately stacking (building up) insulating layers and wiring layers to form a multilayer structure without using a so-called core substrate. In the coreless buildup method, the use of a carrier-attached metal foil has been proposed to facilitate peeling of the support and the multilayer printed wiring board. For example, Patent Document 1 (JP 2005-101137 A) discloses a method for manufacturing a package substrate for mounting semiconductor elements, which includes: attaching an insulating resin layer to the carrier surface of a carrier-attached copper foil to form a support; forming a first wiring conductor on the ultrathin copper layer side of the carrier-attached copper foil through processes such as photoresist processing, patterned electrolytic copper plating, and resist removal; laminating an insulating material and performing heat pressing to form a buildup wiring layer; peeling off the carrier-attached support substrate; and removing the ultrathin copper layer.

[0004] In the manufacturing process of such multilayer printed wiring boards, a heat press process is performed each time an insulating material is laminated, so the metal foil with a carrier is heated at a high temperature for a long time. Furthermore, the heating temperature of this heat press process depends on the curing temperature of the insulating material to be laminated, and therefore the temperature varies depending on the type of insulating material. In this regard, it is known that the higher the heating temperature of the heat press process, the excessively high peel strength and the loss of releasability.

[0005] A technique for providing a release layer containing metal oxide and carbon has been proposed as a carrier-attached metal foil that can cope with the increase in peel strength associated with heating. For example, Patent Document 2 (WO 2019 / 131000) discloses a carrier-attached copper foil that sequentially comprises a carrier, an intermediate layer composed of a specified metal, a release layer containing a metal oxide layer and a carbon layer, an optional etching stopper layer, and an ultrathin copper layer. It is claimed that providing the specified release layer makes it possible to maintain stable peelability even after prolonged heating at high temperatures of 350°C or higher. This document also describes forming the intermediate layer, carbon layer, ultrathin copper layer, etc., by sputtering to further reduce the thickness of the ultrathin copper layer, etc., in the carrier-attached copper foil.

[0006] It is also known that the provision of a metal oxide layer in a carrier-attached metal foil stabilizes peel strength. For example, Patent Document 3 (JP 2017-88970 A) discloses that in a carrier-attached copper foil having a carrier, a nickel-containing intermediate layer, and an ultrathin copper layer in that order, after the intermediate layer is formed and before the ultrathin copper layer is formed, the intermediate layer is dried at 30 to 100°C for 1 to 300 seconds to form an oxide layer (NiO2) on the surface of the nickel. Patent Document 3 discloses that the variation in peel strength can be effectively suppressed after the ultrathin copper layer side of such a carrier-attached copper foil is laminated to an insulating substrate and pressure-bonded at 220°C for 2 hours. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-101137 [Patent Document 2] International Publication No. 2019 / 131000 [Patent Document 3] Japanese Patent Application Laid-Open No. 2017-88970 Summary of the Invention

[0008] As mentioned above, in the manufacturing process of a multilayer printed wiring board, the substrate is heated every time an interlayer insulating material is laminated, and therefore, it is desirable for the metal foil with a carrier to have heat resistance at high temperatures, for example, of 240° C. or higher. In this regard, the metal foil with a carrier having an intermediate layer containing Ni and NiO2 disclosed in Patent Document 3 has a stable peel strength at a low level at a heat press temperature of about 220° C. as mentioned above, but is not suitable for heat press processing at even higher temperatures, such as 240° C. or higher.

[0009] On the other hand, as disclosed in Patent Document 2, by using a metal foil with a carrier having a release layer containing a metal oxide layer and a carbon layer, stable release properties can be maintained even after heating at high temperatures for a long period of time. However, it has been found that when a carbon layer is formed as a release layer and a metal layer is formed thereon, the number of foreign particles on the surface of the metal layer increases compared to when no carbon layer is formed (for example, when a metal layer is formed directly on a glass carrier). There is a concern that these foreign particles may affect circuit formation in subsequent processes. Therefore, there is a need for a metal foil with a carrier that can reduce the number of foreign particles while maintaining heat resistance.

[0010] The present inventors have now discovered that by interposing a release functional layer containing a specified metal oxynitride between the carrier and metal layer of a carrier-attached metal foil, it is possible to provide a carrier-attached metal foil that can suppress the number of foreign particles on the surface of the metal layer, improve circuit formation properties, and maintain stable peel strength even after being heated for a long period of time at high temperatures of 240°C or higher (e.g., 260°C).

[0011] Therefore, the object of the present invention is to provide a metal foil with a carrier that reduces the number of foreign particles on the surface of the metal layer, thereby improving circuit formation properties, and that can maintain stable peelability even after being heated for a long period of time at a high temperature of 240°C or higher (e.g., 260°C).

[0012] According to one aspect of the present invention, Career and a release functional layer provided on the carrier and including a metal oxynitride; a metal layer provided on the release functional layer; A metal foil with a carrier is provided. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic cross-sectional view showing one embodiment of a carrier-attached metal foil of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view showing another embodiment of a metal foil with a carrier according to the present invention. [Figure 3] FIG. 2 is a schematic cross-sectional view showing the layer structure of a metal foil with a carrier of Example 11 (comparison) in the Examples. [Figure 4] FIG. 10 is a diagram showing the change in the number of foreign particles on the surface of a metal layer depending on whether or not a carbon layer is present. DETAILED DESCRIPTION OF THE INVENTION

[0014] Metal foil with carrier An example of a carrier-attached metal foil of the present invention is shown schematically in Figures 1 and 2. As shown in Figures 1 and 2, the carrier-attached metal foil 10 of the present invention comprises, in this order, a carrier 12, a release functional layer 14, and a metal layer 16. The release functional layer 14 is provided on the carrier 12 and contains a metal oxynitride. The metal layer 16 is provided on the release functional layer 14. In this way, by interposing the release functional layer 14 containing a metal oxynitride between the carrier 12 and the metal layer 16 of the carrier-attached metal foil 10, it is possible to provide a carrier-attached metal foil that suppresses the number of foreign particles on the surface of the metal layer 16, improves circuit formability, and maintains stable peel strength even after being heated at a high temperature of 240°C or higher (e.g., 260°C) for a long period of time.

[0015] As described above, the metal foil with a carrier having an intermediate layer containing Ni and NiO, as disclosed in Patent Document 3, exhibits a low and stable peel strength at a heat press temperature of approximately 220°C, but is not suitable for heat press processing at high temperatures such as 240°C or higher. On the other hand, as disclosed in Patent Document 2, a metal foil with a carrier having a release layer containing a metal oxide layer and a carbon layer can maintain stable peelability even after prolonged heating at high temperatures. However, according to the findings of the present inventors, there is a concern that the inclusion of a carbon layer in the release layer may affect circuit formation in subsequent processes. Specifically, the present inventors have found through their investigation that when a carbon layer is formed as a release layer and a metal layer is formed thereon, the number of foreign particles on the surface of the metal layer increases compared to when a carbon layer is not formed. As an example, as shown in Fig. 3, a carrier-attached metal foil 110 having, in this order, a carrier 112 made of glass, an adhesion layer 114 made of Ti, a release aid layer 116 made of Cu, a carbon layer 118 as a release layer, a second metal layer 120 made of Ti, and a first metal layer 122 made of Cu, and a carrier-attached metal foil 110' having the first metal layer 122 made of Cu formed on the carrier 112, are shown in Fig. 4. In Fig. 4, the bar graph on the left represents the number of foreign particles (particle diameter 5 μm or more) present per square centimeter on the surface of the first metal layer 122 of the carrier-attached metal foil 110' without the carbon layer 118, and the bar graph on the right represents the number of foreign particles of the carrier-attached metal foil 110 with the carbon layer 118. As is clear from Fig. 4, the metal foil 110 with a carrier having the carbon layer 118 has three times as many foreign particles on the surface of the first metal layer 122 as the metal foil 110' with a carrier not having the carbon layer 118. There is concern that these foreign particles may affect the circuit formation in the subsequent process.

[0016] In contrast, the carrier-attached metal foil 10 of the present invention has a release functional layer 14 containing a metal oxynitride instead of a carbon layer. Therefore, it is believed that the carrier-attached metal foil 10 can effectively suppress an increase in the number of foreign particles on the surface of the metal layer 16, and as a result, circuit formation in the subsequent process can be performed satisfactorily. Nevertheless, the carrier-attached metal foil 10 having a release functional layer 14 containing a metal oxynitride can maintain stable peel strength even after being heated for a long period of time at a high temperature of 240°C or higher (e.g., 260°C). In other words, it is believed that the inclusion of a metal oxynitride in the release functional layer 14 can suppress an excessive increase in peel strength due to heating. A specific index of peel strength is 30 kgf / cm for 2 hours at 260°C. 2 After pressing under this pressure, the compressive strength is preferably 3 gf / cm or more and less than 50 gf / cm, and more preferably 3 gf / cm or more and less than 30 gf / cm.

[0017] The material of the carrier 12 may be any of glass, ceramics, silicon, resin, and metal. Preferably, the carrier 12 is made of glass, silicon, or ceramic. The carrier 12 may be in the form of a sheet, film, or plate. The carrier 12 may also be a laminate of these sheets, films, and plates. For example, the carrier 12 may be a rigid support such as a glass plate, ceramic plate, silicon wafer, or metal plate, or may be in a non-rigid form such as a metal foil or resin film. Preferred examples of metals constituting the carrier 12 include copper, titanium, nickel, stainless steel, and aluminum. Preferred examples of ceramics include alumina, zirconia, silicon nitride, aluminum nitride, and various other fine ceramics. Preferred examples of resins include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyamide, polyimide, nylon, liquid crystal polymer, polyether ether ketone (PEEK®), polyamideimide, polyethersulfone, polyphenylene sulfide, polytetrafluoroethylene (PTFE), and ethylene tetrafluoroethylene (ETFE). To prevent warping of the coreless support due to heating when mounting electronic elements, a material with a coefficient of thermal expansion (CTE) of less than 25 ppm / K (typically 1.0 ppm / K to 23 ppm / K) is more preferred. Examples of such materials include the various resins mentioned above (particularly low-thermal expansion resins such as polyimide and liquid crystal polymer), glass, silicon, and ceramics. Furthermore, to ensure ease of handling and flatness during chip mounting, the carrier 12 preferably has a Vickers hardness of 100 HV or more, more preferably 150 HV to 2500 HV. As a material that satisfies these properties, the carrier 12 is preferably made of glass, silicon, or ceramics, more preferably made of glass or ceramics, and particularly preferably made of glass. An example of the carrier 12 made of glass is a glass plate.Glass, when used as the carrier 12, offers advantages such as light weight, a low thermal expansion coefficient, high insulation, rigidity, and a flat surface, allowing for extremely smooth surfaces of the metal layer 16. Glass carriers 12 also offer advantages such as surface flatness (coplanarity) that is advantageous for fine circuit formation, chemical resistance in desmearing and various plating processes in wiring manufacturing processes, and the ability to employ chemical separation methods when peeling the carrier 12 from the carrier-attached metal foil 10. Preferred examples of glass constituting the carrier 12 include quartz glass, borosilicate glass, alkali-free glass, soda-lime glass, aluminosilicate glass, and combinations thereof. Alkali-free glass, soda-lime glass, and combinations thereof are more preferred, with alkali-free glass being particularly preferred. Alkali-free glass refers to glass that is essentially free of alkali metals and primarily contains silicon dioxide, aluminum oxide, boron oxide, and alkaline earth metal oxides such as calcium oxide and barium oxide, and further contains boric acid. This alkali-free glass has a stable low coefficient of thermal expansion in the range of 3 ppm / K to 5 ppm / K over a wide temperature range from 0°C to 350°C, which has the advantage of minimizing warping of the glass during processes involving heating. The thickness of the carrier 12 is preferably 100 μm to 2000 μm, more preferably 300 μm to 1800 μm, and even more preferably 400 μm to 1100 μm. A thickness within this range ensures appropriate strength for easy handling, while enabling thinner wiring and reducing warping that occurs when electronic components are mounted.

[0018] The surface of the carrier 12 adjacent to the release functional layer 14 preferably has an arithmetic mean roughness Ra of 0.1 nm to 70 nm, more preferably 0.5 nm to 60 nm, even more preferably 1.0 nm to 50 nm, particularly preferably 1.5 nm to 40 nm, and most preferably 2.0 nm to 30 nm. The smaller the arithmetic mean roughness of the carrier 12 surface, the more desirable the arithmetic mean roughness Ra of the surface of the metal layer 16 opposite the release functional layer 14 (the outer surface of the metal layer 16). This makes it suitable for forming highly fine wiring patterns with lines / spaces (L / S) of 13 μm or less / 13 μm or less (for example, 12 μm / 12 μm to 2 μm / 2 μm) in the wiring formed using the metal layer 16.

[0019] The release functional layer 14 is interposed between the carrier 12 and the metal layer 16 and contributes to stable release of the carrier 12. In order to maintain stable peel strength even after being heated at a high temperature of 240°C or higher (e.g., 260°C) for a long period of time, the release functional layer 14 is a layer containing a metal oxynitride, and preferably contains at least one metal oxynitride selected from the group consisting of TaON, NiON, TiON, NiWON, and MoON, more preferably at least one selected from the group consisting of TaON, NiON, TiON, and MoON, even more preferably at least one selected from the group consisting of TaON, NiON, and TiON, and particularly preferably at least one selected from the group consisting of TaON and TiON. Furthermore, to ensure adhesion between the carrier 12 and the metal layer 16, the surface of the release functional layer 14 facing the carrier 12 preferably contains at least one selected from the group consisting of Cu, Ti, Ta, Cr, Ni, Al, Mo, Zn, W, TiN, and TaN, more preferably at least one selected from the group consisting of Ti, Ta, Cr, Ni, Al, Mo, Zn, W, TiN, and TaN, even more preferably at least one selected from the group consisting of Ti, Ni, Al, Mo, W, TiN, and TaN, and particularly preferably at least one selected from the group consisting of Ti, Al, and TaN. The content of the metal or metal nitride on the surface of the release functional layer 14 facing the carrier 12 is 30 atomic % or more, preferably 40 atomic % or more, more preferably 50 atomic % or more, even more preferably 60 atomic % or more, particularly preferably 70 atomic % or more, and most preferably 80 atomic % or more. The upper limit of the content of the metal or metal nitride is not particularly limited and may be 100 atomic %, but is typically 98 atomic % or less. The above metals or metal nitrides are compatible with the material of the carrier 12 and can ensure adhesion. Controlling the content within the above range is preferable because stable adhesion can be ensured even after heating at high temperatures for a long period of time. These contents are values ​​measured by analysis using X-ray photoelectron spectroscopy (XPS).

[0020] On the other hand, from the same viewpoint as above, the surface of the release functional layer 14 opposite to the carrier 12 (i.e., the metal layer 16 side) preferably contains at least one metal oxynitride selected from the group consisting of TaON, NiON, TiON, NiWON and MoON, more preferably at least one selected from the group consisting of TaON, NiON, TiON and MoON, even more preferably at least one selected from the group consisting of TaON, NiON and TiON, particularly preferably at least one selected from the group consisting of TaON and TiON. In the present invention, the metal oxynitride may contain O and N in any ratio relative to the metal component constituting the metal oxynitride (for example, Ta when the metal oxynitride is TaON). ​​In other words, the metal oxynitride in the present invention nitrogen The compound has the general formula: MO x N y (wherein M is a metal component such as Ta, Ni, Ti, NiW, or Mo, and x and y are each independently a real number greater than 0). However, on the surface of the release functional layer 14 opposite the carrier 12, the atomic ratio of O to the metal components constituting the metal oxynitride is preferably 4% or more (more preferably 5% or more and 120% or less), and the atomic ratio of N to the metal components constituting the metal oxynitride is preferably 20% or more (more preferably 25% or more and 45% or less). On the surface of the release functional layer 14 opposite the carrier 12, the content of the metal components constituting the metal oxynitride is preferably 20 atomic % or more and 80 atomic % or less, more preferably 25 atomic % or more and 75 atomic % or less, even more preferably 30 atomic % or more and 70 atomic % or less, and particularly preferably 35 atomic % or more and 68 atomic % or less.

[0021] The release functional layer 14 preferably does not contain a carbon layer (i.e., a layer primarily composed of carbon) because this effectively reduces the number of foreign particles on the surface of the metal layer 16. However, the release functional layer 14 may contain unavoidable impurities resulting from the raw material components and the film-forming process. Furthermore, although not particularly limited, the presence of carbon dioxide and other impurities is acceptable if the release functional layer 14 is exposed to the atmosphere after formation. From this perspective, the carbon content of the release functional layer 14 measured by XPS may be below the lower detection limit, but is typically 3 atomic % or less, and more typically 1 atomic % or less. Note that the carbon content measured by XPS at the outermost surface (0 nm depth) tends to be higher due to contamination caused by exposure to the atmosphere. Therefore, the carbon content of the release functional layer 14 is taken as the value at a depth of 2 nm (in terms of SiO2 sputtering rate) from the surface (i.e., the surface of the release functional layer 14 opposite the carrier 12). The release functional layer 14 may be produced by any method, but is particularly preferably a layer formed by magnetron sputtering using a target, as this can improve the uniformity of the film thickness distribution.

[0022] The thickness of the release functional layer 14 is preferably 5 nm to 500 nm, more preferably 10 nm to 400 nm, even more preferably 20 nm to 200 nm, and particularly preferably 30 nm to 100 nm. This thickness is a value measured by analyzing the layer cross section with a transmission electron microscope energy dispersive X-ray spectrometer (TEM-EDX).

[0023] The release functional layer 14 may be a single-layer structure as shown in FIG. 1, or may be a two-layer or more structure as shown in FIG.

[0024] According to a preferred embodiment of the present invention, the release functional layer 14 includes an adhesive layer 14a and a release layer 14b, as shown in FIG.

[0025] The adhesion layer 14a has the function of relatively improving the adhesion at the interface between the carrier 12 and the release functional layer 14, thereby causing stable release from the interface between the release functional layer 14 and the metal layer 16. The adhesion layer 14a is preferably a layer containing at least one selected from the group consisting of Cu, Ti, Ta, Cr, Ni, Al, Mo, Zn, W, TiN, and TaN, more preferably at least one selected from the group consisting of Ti, Ta, Cr, Ni, Al, Mo, Zn, W, TiN, and TaN, even more preferably at least one selected from the group consisting of Ti, Ni, Al, Mo, W, TiN, and TaN, and particularly preferably at least one selected from the group consisting of Ti, Al, and TaN. The adhesion layer 14a preferably has a metal or metal nitride content of 30 atomic % or more, more preferably 40 atomic % or more, even more preferably 50 atomic % or more, even more preferably 60 atomic % or more, particularly preferably 70 atomic % or more, and most preferably 80 atomic % or more, as measured by X-ray photoelectron spectroscopy (XPS). The upper limit of the metal or metal nitride content in the adhesion layer 14a is not particularly limited and may be 100 atomic %, but 98 atomic % or less is practical. Furthermore, although not particularly limited, the presence of oxygen mixed in when the adhesion layer 14a is exposed to the atmosphere after deposition is acceptable. The adhesion layer 14a typically has an oxygen content of 0.1 atomic % to 10 atomic %, more typically 0.3 atomic % to 7 atomic %, and even more typically 0.5 atomic % to 5 atomic %. The adhesion layer 14a may be produced by any method, but is preferably formed by magnetron sputtering using a target, as this improves the uniformity of the film thickness distribution. The thickness T1 of the adhesion layer 14a is preferably 5 nm to 400 nm, more preferably 10 nm to 300 nm, even more preferably 50 nm to 200 nm, and particularly preferably 50 nm to 100 nm. This thickness is measured by analyzing the layer cross section with a transmission electron microscope energy dispersive X-ray spectrometer (TEM-EDX).

[0026] The release layer 14b is provided on the adhesion layer 14a and is preferably a layer containing at least one metal oxynitride selected from the group consisting of TaON, NiON, TiON, NiWON, and MoON, more preferably at least one selected from the group consisting of TaON, NiON, TiON, and MoON, even more preferably at least one selected from the group consisting of TaON, NiON, and TiON, and particularly preferably at least one selected from the group consisting of TaON and TiON. The release layer 14b preferably has an atomic ratio of O to the metal components constituting the metal oxynitride of 4% or more (more preferably 5% to 120%) and an atomic ratio of N to the metal components constituting the metal oxynitride of 20% or more (more preferably 25% to 45%), as measured by X-ray photoelectron spectroscopy (XPS). The release layer 14b preferably has a metal oxynitride content of 20 atomic % to 80 atomic % as measured by X-ray photoelectron spectroscopy (XPS), more preferably 25 atomic % to 75 atomic %, even more preferably 30 atomic % to 70 atomic %, and particularly preferably 35 atomic % to 68 atomic %. The release layer 14b may contain inevitable impurities resulting from raw material components, the film formation process, etc. The release layer 14b may be produced by any method, but is preferably formed by reactive sputtering, which uses a metal target or a metal nitride target and performs sputtering in an atmosphere containing oxygen and / or nitrogen, because the film thickness can be easily controlled by adjusting the film formation time. The release layer 14b may also be formed by treating the surface of the adhesion layer 14a in oxygen plasma and / or nitrogen plasma using a commercially available plasma ashing device. Furthermore, when the adhesion layer 14a contains a metal nitride (i.e., TiN and / or TaN), the peeling layer 14b can also be produced by exposing the adhesion layer 14a formed in a vacuum to an oxidizing atmosphere (e.g., air).

[0027] The thickness T2 of the release layer 14b is preferably 1 nm to 150 nm, more preferably 3 nm to 130 nm, even more preferably 10 nm to 120 nm, and particularly preferably 50 nm to 100 nm. The release layer 14b can be formed thicker than conventional carbon release layers (carbon layers). Increasing the thickness T2 of the release layer 14b (e.g., T2 is 50 nm or greater) allows the release layer 14b to function as an etching stopper layer. Specifically, the metal oxynitride constituting the release layer 14b is less soluble in flash etching solutions (e.g., Cu flash etching solutions), thereby providing excellent chemical resistance to the flash etching solutions. Therefore, the release layer 14b is less susceptible to etching by flash etching solutions than the metal layer 16 described below, and therefore can also function as an etching stopper layer.

[0028] The thickness T2 of the release layer 14b can be determined by performing a depth direction elemental analysis of the carrier-attached metal foil 10 using X-ray photoelectron spectroscopy (XPS) under the conditions described in the Examples below. It should be noted that, even when the same etching conditions are used, it is difficult to obtain the actual value of the thickness T2 of the release layer 14b in depth direction elemental analysis using XPS because the etching rate varies depending on the type of material. Therefore, the thickness T2 is determined as the SiO2 equivalent thickness calculated from the time required for etching using the etching rate calculated from an SiO2 film with a known thickness. This allows the thickness to be uniquely determined, enabling quantitative evaluation.

[0029] In the carrier-attached metal foil 10, the ratio T1 / T2, which is the ratio of the thickness T1 of the adhesive layer 14a to the thickness T2 of the release layer 14b, is preferably 0.03 to 400, more preferably 0.07 to 300, even more preferably 0.1 to 200, and particularly preferably 0.38 to 100. By setting T1 / T2 within the above range, it is possible to suppress deterioration of the release function of the release function layer 14, even when heat treatment is performed over a wide temperature range, including a high temperature range of, for example, 100°C to 260°C. The mechanism by which the thickness ratio of the adhesive layer 14a to the release layer 14b affects the releasability is not necessarily clear, but it is thought that changing this thickness ratio changes the diffusion behavior of the elements constituting each layer of the carrier-attached metal foil 10 during heating.

[0030] The metal layer 16 is a layer made of a metal. The metal layer 16 is preferably made of at least one metal or alloy selected from the group consisting of transition elements of groups 4, 5, 6, 9, 10, and 11, and Al; more preferably at least one metal or alloy selected from the group consisting of transition elements of groups 4 and 11, Pt, Al, Nb, Co, Ni, and Mo; even more preferably at least one metal or alloy selected from the group consisting of transition elements of group 11, Pt, Ti, Al, and Mo; even more preferably at least one metal or alloy selected from the group consisting of Cu, Au, Pt, Ti, and Mo; particularly preferably at least one metal or alloy selected from the group consisting of Cu, Au, and Pt; and most preferably Cu. The metal constituting the metal layer 16 may be a pure metal or an alloy. The metal layer 16 preferably has a metal content of 60 atomic % or more, more preferably 70 atomic % or more, even more preferably 80 atomic % or more, and particularly preferably 90 atomic % or more, as measured by X-ray photoelectron spectroscopy (XPS). The upper limit of the metal content in the metal layer 16 is not particularly limited; it may be 100 atomic %, but is typically 98 atomic % or less. The metal constituting the metal layer 16 may contain unavoidable impurities resulting from raw material components, the film formation process, and the like. The metal layer 16 is preferably a layer formed by a vapor phase method such as sputtering. The metal layer 16 is preferably an unroughened metal layer, but may also be a metal layer that has undergone secondary roughening by preparatory roughening, soft etching, cleaning, or oxidation-reduction treatment, as long as it does not interfere with the formation of a wiring pattern during the manufacture of a printed wiring board. The thickness T3 of the metal layer 16 is preferably 10 to 1000 nm, more preferably 20 to 900 nm, even more preferably 30 to 700 nm, particularly preferably 50 to 600 nm, particularly preferably 70 to 500 nm, and most preferably 100 to 400 nm. This thickness is measured by analyzing the cross section of the layer with a transmission electron microscope energy dispersive X-ray spectrometer (TEM-EDX).The metal layer 16 having a thickness in this range is preferably produced by sputtering in terms of the in-plane uniformity of the deposited film thickness and productivity in sheet or roll form.

[0031] The surface of the metal layer 16 opposite to the release functional layer 14 (the outer surface of the metal layer 16) preferably has an arithmetic mean roughness Ra of 1.0 nm to 100 nm, more preferably 2.0 nm to 40 nm, even more preferably 3.0 nm to 35 nm, particularly preferably 4.0 nm to 30 nm, and most preferably 5.0 nm to 15 nm. The smaller the arithmetic mean roughness, the more likely it is that a printed wiring board manufactured using the carrier-attached metal foil 10 will have a highly refined wiring pattern with a line / space (L / S) of 13 μm or less / 13 μm or less (for example, from 12 μm / 12 μm to 2 μm / 2 μm). N It is suitable for forming.

[0032] The metal layer 16 may be a single-layer structure or a structure of two or more layers. Furthermore, as long as the carrier-attached metal foil 10 includes the carrier 12, the release functional layer 14, and the metal layer 16 in this order, other layers may be included as long as the original functions of the carrier-attached metal foil 10 are not impaired. Examples of such other layers include an etching stopper layer as shown in Patent Document 2 (WO 2019 / 131000), and a barrier layer (e.g., a layer composed of Ti, Ta, Ni, W, Cr, Pd, or a combination thereof) for suppressing the formation of an intermetallic compound between the metal (e.g., Au or Pt) constituting the metal layer 16 and the metal (e.g., Cu) constituting the wiring layer that may be formed on the metal layer 16 (i.e., the surface of the carrier-attached metal foil 10 opposite the carrier 12). Furthermore, the carrier-attached metal foil 10 may be configured to include the above-mentioned various layers in order, symmetrically arranged on both sides of the carrier 12.

[0033] The overall thickness of the carrier-attached metal foil 10 is not particularly limited, but is preferably 500 μm to 3000 μm, more preferably 700 μm to 2500 μm, even more preferably 900 μm to 2000 μm, and particularly preferably 1000 μm to 1700 μm. The shape and size of the carrier-attached metal foil 10 are not particularly limited, but it is preferably a rectangular or square shape with one side measuring 10 cm or more, more preferably 20 cm or more, and even more preferably 25 cm or more. When the carrier-attached metal foil 10 is rectangular or square, there is no particular limit to the size, but one guideline for the upper limit is to set one side to 1000 cm. Furthermore, the carrier-attached metal foil 10 is in a form that can be handled independently before and after the formation of wiring.

[0034] Manufacturing method of metal foil with carrier The carrier-attached metal foil 10 of the present invention can be produced by preparing the above-described carrier 12 and forming a release functional layer 14 (e.g., an adhesive layer 14a and a release layer 14b) and a metal layer 16 on the carrier 12. The release functional layer 14 and the metal layer 16 are preferably formed by physical vapor deposition (PVD) in order to facilitate fine pitches through ultra-thinning. Examples of physical vapor deposition (PVD) methods include sputtering, vacuum deposition, and ion plating. However, sputtering is most preferred because it allows for thickness control over a wide range, such as from 0.05 nm to 5000 nm, and ensures uniformity of film thickness over a wide width or area. Film formation by physical vapor deposition (PVD) is not particularly limited and can be performed using a known vapor deposition apparatus under known conditions. For example, when sputtering is employed, various known sputtering methods may be used, such as magnetron sputtering, two-pole sputtering, and facing target sputtering. However, magnetron sputtering is preferred because of its high film formation rate and high productivity. Sputtering may be performed using either a DC (direct current) or RF (radio frequency) power source. Furthermore, while a widely known plate-shaped target may be used, a cylindrical target is preferable from the viewpoint of target utilization efficiency. The following describes the film formation of the adhesion layer 14a, the release layer 14b, and the metal layer 16 by physical vapor deposition (PVD) (preferably sputtering).

[0035] The adhesion layer 14a is preferably formed by physical vapor deposition (PVD) (preferably sputtering) using a target composed of at least one metal or metal nitride selected from the group consisting of Cu, Ti, Ta, Cr, Ni, Al, Mo, Zn, W, TiN, and TaN. Magnetron sputtering is preferably performed in a non-oxidizing atmosphere to improve the uniformity of the film thickness distribution. The target purity is preferably 99.9 wt% or higher. The gas used for sputtering is preferably an inert gas such as argon gas. The flow rate of the argon gas or the like can be determined appropriately depending on the sputtering chamber size and film formation conditions, and is not particularly limited. Furthermore, to ensure continuous film formation without operational problems such as abnormal discharge or poor plasma irradiation, the pressure during film formation is preferably in the range of 0.1 Pa to 20 Pa. This pressure range can be set by adjusting the film formation power and the flow rate of the argon gas or the like depending on the device structure, capacity, exhaust capacity of the vacuum pump, rated capacity of the film formation power supply, etc. In addition, the sputtering power was set at 0.05 W / cm per unit area of ​​the target, taking into consideration the uniformity of the film thickness and productivity. 2 More than 10.0W / cm 2 It may be set appropriately within the following range.

[0036] The release layer 14b is preferably formed by physical vapor deposition (PVD) (preferably sputtering) in an atmosphere containing oxygen and / or nitrogen using a target composed of at least one metal or metal nitride selected from the group consisting of Ta, Ni, Ti, NiW, Mo, TiN, and TaN. This reactive sputtering method is preferred because it allows for easy control of the film thickness. The purity of the target is preferably 99.9% or higher. The gas used for sputtering preferably contains an inert gas (e.g., argon gas) as well as a gas for generating a metal oxynitride (e.g., oxygen gas, nitric oxide gas, and nitrogen dioxide gas). The flow rates of these gases are not particularly limited and can be determined appropriately depending on the size of the sputtering chamber and the film formation conditions. Furthermore, from the perspective of continuous film formation without operational problems such as abnormal discharge, the pressure during film formation is preferably in the range of 0.1 Pa to 1.0 Pa. This pressure range can be set by adjusting the film formation power and the flow rates of the above gases depending on the device structure, capacity, exhaust capacity of the vacuum pump, rated capacity of the film formation power supply, etc. In addition, the sputtering power was set at 0.05 W / cm per unit area of ​​the target, taking into consideration the uniformity of the film thickness and productivity. 2 More than 15.0W / cm 2 It may be set appropriately within the following range.

[0037] The physical vapor deposition (PVD) method (preferably sputtering) for forming the metal layer 16 is preferably performed in an inert atmosphere such as argon using a target composed of at least one metal selected from the group consisting of transition elements of groups 4, 5, 6, 9, 10, and 11, and Al. The target is preferably composed of a pure metal or alloy, but may contain unavoidable impurities. The purity of the target is preferably 99.9% or higher, more preferably 99.99%, and even more preferably 99.999% or higher. To prevent temperature increases during vapor deposition of the metal layer 16, a stage cooling mechanism may be installed during sputtering. Furthermore, to ensure stable film formation without operational problems such as abnormal discharge or poor plasma irradiation, the pressure during film formation is preferably in the range of 0.1 Pa to 20 Pa. This pressure range can be set by adjusting the film formation power and argon gas flow rate depending on the device structure, capacity, exhaust capacity of the vacuum pump, and rated capacity of the film formation power supply. In addition, the sputtering power was set at 0.05 W / cm per unit area of ​​the target, taking into consideration the uniformity of the film thickness and productivity. 2 More than 10.0W / cm 2 It may be set appropriately within the following range. [Example]

[0038] The present invention is further illustrated by the following examples.

[0039] Example 1 2, a release functional layer 14 (an adhesive layer 14a and a release layer 14b) and a metal layer 16 were formed in this order on a glass sheet as a carrier 12 to produce a carrier-attached metal foil 10. The specific procedure is as follows.

[0040] (1) Career preparation A glass sheet with a thickness of 1.1 mm (material: soda lime glass, arithmetic mean roughness Ra: 0.6 nm) was prepared.

[0041] (2) Formation of an adhesive layer A TaN layer having a thickness of 100 nm was formed as an adhesive layer 14a by sputtering on the carrier 12. This sputtering was carried out using the following apparatus under the following conditions. - Equipment: Single-wafer magnetron sputtering equipment (Canon Tokki Corporation, MLS464) - Target: 8-inch (203.2 mm) diameter TaN target (purity 99.95% or higher) - Ultimate vacuum: 1×10 -4 Less than Pa - Gas: Argon gas (flow rate: 100sccm) - Sputtering pressure: 0.35 Pa - Sputtering power: 1000W (3.1W / cm 2 ) - Temperature during film formation: 40℃

[0042] (3) Formation of a peeling layer The sample on which the adhesive layer 14a was formed was removed from the vacuum and exposed to the atmosphere for 5 minutes to perform a surface oxidation treatment (natural oxidation) of the adhesive layer 14a. This surface oxidation treatment formed a TaON layer as the peeling layer 14b.

[0043] (4) Formation of metal layer A Cu layer having a thickness of 300 nm was formed as the metal layer 16 on the release layer 14b by sputtering using the following apparatus and conditions, thereby obtaining a metal foil 10 with a carrier. - Equipment: Single-wafer DC sputtering equipment (Canon Tokki Corporation, MLS464) - Target: 8-inch (203.2 mm) diameter Cu target (purity 99.98%) - Ultimate vacuum: 1×10 -4 Less than Pa - Gas: Argon gas (flow rate: 100sccm) - Sputtering pressure: 0.35 Pa - Sputtering power: 1000W (3.1W / cm 2 ) - Temperature during film formation: 40℃

[0044] Example 2 The carrier-attached metal foil 10 was prepared in the same manner as in Example 1, except that instead of performing surface oxidation treatment on the adhesion layer 14a by exposure to the atmosphere, a TiON layer was formed as the release layer 14b by reactive sputtering as follows.

[0045] (Formation of TiON layer) A TiON layer having a target thickness of about 100 nm was formed on the surface of the adhesive layer 14a by reactive sputtering using the following apparatus and conditions. - Equipment: Single-wafer DC sputtering equipment (Canon Tokki Corporation, MLS464) - Target: 8-inch (203.2 mm) diameter TiN target (purity 99.95% or higher) - Ultimate vacuum: 1×10 -4 Less than Pa - Gas: Argon gas (flow rate: 90 sccm) and oxygen gas (flow rate: 10 sccm) - Sputtering pressure: 0.35 Pa - Sputtering power: 100W (0.3W / cm 2 ) - Temperature during film formation: 40℃

[0046] Example 3 A carrier-attached metal foil 10 was prepared in the same manner as in Example 1, except that (i) a Ti layer was formed as the adhesion layer 14a instead of a TaN layer, and (ii) instead of performing surface oxidation treatment on the adhesion layer 14a by exposure to the atmosphere, a TaON layer was formed by reactive sputtering as follows.

[0047] (Formation of Ti layer) A Ti layer having a thickness of 100 nm was formed as an adhesive layer 14a by sputtering on the carrier 12. This sputtering was carried out using the following apparatus under the following conditions. - Equipment: Single-wafer magnetron sputtering equipment (Canon Tokki Corporation, MLS464) - Target: 8-inch (203.2 mm) diameter Ti target (purity 99.999%) - Ultimate vacuum: 1×10 -4 Less than Pa - Gas: Argon gas (flow rate: 100sccm) - Sputtering pressure: 0.35 Pa - Sputtering power: 1000W (3.1W / cm 2 ) - Temperature during film formation: 40℃

[0048] (Formation of TaON layer) A TaON layer having a target thickness of about 100 nm was formed on the surface of the adhesive layer 14a by reactive sputtering using the following apparatus and conditions. - Equipment: Single-wafer DC sputtering equipment (Canon Tokki Corporation, MLS464) - Target: 8-inch (203.2 mm) diameter TaN target (purity 99.98%) - Ultimate vacuum: 1×10 -4 Less than Pa - Gas: Argon gas (flow rate: 90 sccm) and oxygen gas (flow rate: 10 sccm) - Sputtering pressure: 0.35 Pa - Sputtering power: 100W (0.3W / cm 2 ) - Temperature during film formation: 40℃

[0049] Example 4 A carrier-attached metal foil 10 was produced in the same manner as in Example 2, except that a 100 nm thick Ti layer was formed as the adhesion layer 14a in place of the TaN layer using the same equipment and conditions as in Example 3.

[0050] Example 5 A carrier-attached metal foil 10 was produced in the same manner as in Example 3, except that an Al layer was formed as the adhesive layer 14a instead of the Ti layer.

[0051] (Formation of Al layer) An Al layer having a thickness of 100 nm was formed as an adhesive layer 14a by sputtering on the carrier 12. This sputtering was carried out using the following apparatus under the following conditions. - Equipment: Single-wafer magnetron sputtering equipment (Canon Tokki Corporation, MLS464) - Target: 8-inch (203.2 mm) diameter Al target (purity 99.95% or higher) - Ultimate vacuum: 1×10 -4 Less than Pa - Gas: Argon gas (flow rate: 100sccm) - Sputtering pressure: 0.35 Pa - Sputtering power: 1000W (3.1W / cm 2 ) - Temperature during film formation: 40℃

[0052] Example 6 A carrier-attached metal foil 10 was produced in the same manner as in Example 2, except that a 100 nm thick Al layer was formed as the adhesion layer 14a in place of the TaN layer using the same equipment and conditions as in Example 5.

[0053] Example 7 (comparison) The carrier-attached metal foil 10 was prepared in the same manner as in Example 1, except that only a Ta layer (adhesion layer 14a) was formed as the release functional layer 14 instead of a TaN layer (adhesion layer 14a) and a TaON layer (release layer 14b).

[0054] (Formation of Ta layer) A Ta layer having a thickness of 100 nm was formed as an adhesive layer 14a by sputtering on the carrier 12. This sputtering was carried out using the following apparatus under the following conditions. - Equipment: Single-wafer magnetron sputtering equipment (Canon Tokki Corporation, MLS464) - Target: 8-inch (203.2 mm) diameter Ta target (purity 99.98%) - Ultimate vacuum: 1×10 -4 Less than Pa - Gas: Argon gas (flow rate: 100sccm) - Sputtering pressure: 0.35 Pa - Sputtering power: 1000W (3.1W / cm2 ) - Temperature during film formation: 40℃

[0055] Example 8 (comparison) A carrier-attached metal foil 10 was produced in the same manner as in Example 2, except that a Ta layer was formed as the release layer 14b instead of the TiON layer.

[0056] (Formation of Ta layer) A Ta layer having a thickness of 100 nm was formed as a release layer 14b on the adhesive layer 14a by reactive sputtering using the following apparatus and conditions. - Equipment: Single-wafer DC sputtering equipment (Canon Tokki Corporation, MLS464) - Target: 8-inch (203.2 mm) diameter Ta target (purity 99.98%) - Ultimate vacuum: 1×10 -4 Less than Pa - Gas: Argon gas (flow rate: 100sccm) - Sputtering pressure: 0.35 Pa - Sputtering power: 100W (0.3W / cm 2 ) - Temperature during film formation: 40℃

[0057] Example 9 (comparison) A carrier-attached metal foil 10 was produced in the same manner as in Example 1, except that the release layer 14b was not formed (that is, the surface of the adhesive layer 14a was not oxidized).

[0058] Example 10 (comparison) As the peeling layer 14b, a Ta / TaO layer was used instead of a TiON layer. x A carrier-attached metal foil 10 was produced in the same manner as in Example 2, except that a Ta layer was formed on the adhesive layer 14a. Specifically, a Ta layer having a thickness of 100 nm was formed on the adhesive layer 14a using the same equipment and conditions as in Example 8. The sample on which the Ta layer was formed was taken out of the vacuum and exposed to the atmosphere for 1 minute, thereby subjecting the Ta layer to surface oxidation treatment (natural oxidation). By doing so, a Ta / TaO xA layer was formed.

[0059] Example 11 (comparison) 3, a release functional layer (an adhesive layer 114, a release auxiliary layer 116, and a carbon layer 118 as a release layer), a second metal layer 120, and a first metal layer 122 were formed in this order on a carrier 112 to produce a carrier-attached metal foil 110. The specific procedure is as follows.

[0060] (1) Career preparation A glass sheet with a thickness of 1.1 mm (material: soda lime glass, arithmetic mean roughness Ra: 0.6 nm) was prepared.

[0061] (2) Formation of an adhesive layer A Ti layer having a thickness of 100 nm was formed as an adhesive layer 114 by sputtering on the carrier 112. This sputtering was carried out using the following apparatus under the following conditions. - Equipment: Single-wafer magnetron sputtering equipment (Canon Tokki Corporation, MLS464) - Target: 8-inch (203.2 mm) diameter Ti target (purity 99.999%) - Ultimate vacuum: 1×10 -4 Less than Pa - Gas: Argon gas (flow rate: 100sccm) - Sputtering pressure: 0.35 Pa - Sputtering power: 1000W (3.1W / cm 2 ) - Temperature during film formation: 40℃

[0062] (3) Formation of a peeling aid layer A Cu layer having a thickness of 100 nm was formed as a peeling auxiliary layer 116 by sputtering on the adhesive layer 114. This sputtering was carried out using the following apparatus under the following conditions. - Equipment: Single-wafer magnetron sputtering equipment (Canon Tokki Corporation, MLS464) - Target: 8-inch (203.2 mm) diameter copper target (purity 99.98%) - Ultimate vacuum: 1×10 -4 Less than Pa - Gas: Argon gas (flow rate: 100sccm) - Sputtering pressure: 0.35 Pa - Sputtering power: 1000W (6.2W / cm 2 ) - Temperature during film formation: 40℃

[0063] (4) Formation of carbon layer On the release assisting layer, an amorphous carbon layer having a thickness of 6 nm was formed by sputtering as the carbon layer 118. This sputtering was carried out using the following apparatus under the following conditions. - Equipment: Single-wafer magnetron sputtering equipment (Canon Tokki Corporation, MLS464) - Target: 8-inch (203.2 mm) diameter carbon target (99.999% purity) - Ultimate vacuum: 1×10 -4 Less than Pa - Gas: Argon gas (flow rate: 100sccm) - Sputtering pressure: 0.35 Pa - Sputtering power: 250W (0.7W / cm 2 ) - Temperature during film formation: 40℃

[0064] (5) Formation of the second metal layer A Ti layer having a thickness of 100 nm was formed as the second metal layer 120 on the carbon layer by sputtering using the following apparatus and conditions. - Equipment: Single-wafer magnetron sputtering equipment (Canon Tokki Corporation, MLS464) - Target: 8-inch (203.2 mm) diameter Ti target (purity 99.999%) - Gas: Argon gas (flow rate: 100sccm) - Ultimate vacuum: 1×10 -4 Less than Pa - Sputtering pressure: 0.35 Pa - Sputtering power: 1000W (3.1W / cm2 )

[0065] (6) Formation of the first metal layer On the second metal layer, a Cu layer having a thickness of 300 nm was formed by sputtering as the first metal layer 122. This sputtering was carried out using the following apparatus under the following conditions. Equipment: Single-wafer magnetron sputtering equipment (Canon Tokki Corporation, MLS464) - Target: 8-inch (203.2 mm) diameter Cu target (purity 99.99%) - Ultimate vacuum: 1×10 -4 Less than Pa - Gas: Argon gas (flow rate: 100sccm) - Sputtering pressure: 0.35 Pa - Sputtering power: 1000W (3.1W / cm 2 ) - Temperature during film formation: 40℃

[0066] evaluation Various evaluations were carried out on the carrier-attached metal foils of Examples 1 to 11 as shown below. The evaluation results are shown in Tables 1 and 2. Table 2 also shows the compositions of the adhesion layer (including the release auxiliary layer in the case of Example 11) and the release layer as the release functional layer.

[0067] <Evaluation 1: Semi-quantitative analysis of peeling layer> For Example 1, a depth direction analysis of the produced carrier-attached metal foil 10 was carried out by X-ray photoelectron spectroscopy (XPS) under the following measurement and analysis conditions. This analysis was carried out after peeling the metal layer 16 from the carrier-attached metal foil 10, by digging down from the exposed surface of the release functional layer 14 in the depth direction using Ar ion etching under the following conditions.

[0068] (Ar ion etching conditions) - Accelerating voltage: 500V - Etching area: 2mm x 2mm - Etching rate: 4.4nm / min in SiO2 equivalent

[0069] (Measurement conditions) - Equipment: X-ray photoelectron spectrometer (ULVAC-PHI, Versa Probe III) - Excitation X-ray: Monochromated Al-Kα line (1486.6 eV) - Output: 50W - Acceleration voltage: 15 kV - X-ray irradiation diameter: 200μmφ - Measurement area: 200μmφ - Pass energy: 26.0 eV - Energy step: 0.1 eV -Neutralization gun: Yes - Measurement element and orbital: (sweep number: ratio: cycle number) C 1s:(3:6:1) N 1s:(30:6:1) O 1s:(5:6:1) Cu 2p3:(2:6:1) Ta 4d: (30:6:1)

[0070] (Analysis conditions) XPS data was analyzed using data analysis software (ULVAC-PHI, Inc., "Multipack Ver. 9.4.0.7"). Smoothing was performed at 15 points, and Shirley background mode was used. The background ranges for each element in semi-quantitative calculations are as follows: - C 1s: 280.0~292.0eV - N 1s (including Ta 4p3): 392.0~410.0eV - O 1s: 528.0~540.0eV - Cu 2p3: 927.0~939.0eV - Ta 4d: 212.0~250.0eV

[0071] However, because the N 1s peak interferes with the Ta 4p3 peak, the semi-quantitative value of N 1s was calculated from the N 1s peak area obtained by waveform resolution analysis. The energy ranges of the N 1s and Ta 4p3 peak positions in waveform resolution analysis are as follows. A Gaussian function was used as the fitting function in waveform resolution analysis. - N 1s: 395.9~398.2eV - Ta 4p3 (metal): 399.5~400.5eV - Ta 4p3 (oxide): 404.11~405.11eV

[0072] The results of the semi-quantitative values ​​in the depth direction for the carrier-attached metal foil 10 of Example 1 were as shown in Table 1. As is clear from Table 1, in the carrier-attached metal foil 10 of Example 1, there is a region from the surface (sputtering depth 0 nm) of the release functional layer 14 to a depth of 2.9 nm where the atomic ratio of O to the metal components (i.e., Ta) constituting the TaON layer is 4% or more, and the atomic ratio of N to the metal components constituting the metal oxynitride is 20% or more. Therefore, the thickness of the TaON layer (release layer 14b) in the carrier-attached metal foil 10 of Example 1 is estimated to be approximately 3 nm in SiO2 equivalent.

[0073] [Table 1]

[0074] <Evaluation 2: Carrier-metal layer peelability> The peel strength after vacuum hot pressing as the thermal history of the carrier-attached metal foil 10, 110 was measured as follows: After panel electrolytic copper plating of 18 μm in thickness was performed on the metal layer 16 side or the first metal layer 122 side of the carrier-attached metal foil 10, 110, the thermal history was 260° C. for 2 hours at 30 kgf / cm 2The copper clad laminate was pressed with a pressure of 1000 kJ / cm. The peel strength (gf / cm) of the obtained copper clad laminate was measured in accordance with JIS C 6481-1996 when the electrolytic copper plating layer integrated with the metal layer 16 or the first metal layer 122 was peeled off. The measurement width was 50 mm and the measurement length was 20 mm. The peel strength (average value) thus obtained was ranked and evaluated according to the following criteria. The results are shown in Table 2. - Rating A: Peel strength is 3 gf / cm or more and less than 30 gf / cm - Rating B: Peel strength is 30 gf / cm or more and less than 50 gf / cm - Rating C: Peel strength is less than 3 gf / cm or more than 50 gf / cm (including non-peeling), or peeling occurs between the carrier and the release functional layer, making it impossible to evaluate

[0075] <Evaluation 3: Number of foreign particles> The number of foreign particles on the surface of the carrier-attached metal foil 10, 110 facing the metal layer 16 or the surface facing the first metal layer 122 was measured as follows. First, a foreign matter inspection device (HS930, manufactured by Toray Engineering Co., Ltd.) was used to measure the total number of foreign matter particles (particle size 5 μm or larger) on a specified area of ​​the carrier-attached metal foil surface. Next, this total number was divided by the measured area to calculate the number of foreign matter particles per unit area (1 square centimeter). Note that the region up to 10 mm from the edge of the carrier-attached metal foil was excluded from the measurement range. The number of foreign matter particles 5 μm or larger per unit area thus obtained was ranked and evaluated according to the following criteria. The results are shown in Table 2. - Rating A: The number of foreign particles of 5 μm or more per square centimeter is less than 0.20 - Rating B: The number of foreign particles of 5 μm or more per square centimeter is 0.20 or more and less than 0.50 - Rating C: The number of foreign particles of 5 μm or more per square centimeter is 0.50 or more

[0076] <Overall rating> The overall evaluation was determined based on the results of evaluations 2 and 3. That is, if the evaluation result of evaluation 2 was A or B and the evaluation result of evaluation 3 was A or B, it was judged as passing, and if not, it was judged as failing. The results are shown in Table 2.

[0077] [Table 2]

Claims

1. A carrier made of glass, silicon, ceramics, or metal; a release functional layer provided on the carrier and including a metal oxynitride; a metal layer formed on the release functional layer and composed of at least one metal or alloy selected from the group consisting of Cu, Au, and Pt; A metal foil with a carrier comprising: The release functional layer is an adhesion layer provided on the carrier and containing at least one selected from the group consisting of Cu, Ti, Ta, Cr, Ni, Al, Mo, Zn, W, TiN, and TaN; a release layer provided on the adhesion layer and containing at least one metal oxynitride selected from the group consisting of TaON, NiON, TiON, NiWON, and MoON; Including, The metal foil with a carrier is subjected to panel electrolytic copper plating of 18 μm on the metal layer side to form an electrolytic copper plating layer, and then pressed at 260°C for 2 hours at a pressure of 30 kgf / cm to produce a copper-clad laminate. When the electrolytic copper plating layer integrated with the metal layer is peeled from the copper-clad laminate in accordance with JIS C 6481-1996 under conditions of a measurement width of 50 mm and a measurement length of 20 mm, the peel strength of the metal foil with a carrier is 3 gf / cm or more and less than 50 gf / cm.

2. The metal foil with a carrier according to claim 1, wherein the adhesion layer contains 30 atomic % or more of at least one selected from the group consisting of Cu, Ti, Ta, Cr, Ni, Al, Mo, Zn, W, TiN and TaN.

3. The thickness T of the adhesive layer １ The metal foil with a carrier according to claim 1 or 2, wherein the average particle diameter is 5 nm or more and 400 nm or less.

4. The metal foil with a carrier according to any one of claims 1 to 3, wherein the release layer has an atomic ratio of O to the metal components constituting the metal oxynitride of 4% or more and an atomic ratio of N to the metal components constituting the metal oxynitride of 20% or more, as measured by X-ray photoelectron spectroscopy (XPS).

5. The thickness T of the release layer ２ The metal foil with a carrier according to any one of claims 1 to 4, wherein the average particle size is 1 nm or more and 150 nm or less.

6. The thickness T of the release layer ２ The thickness T of the adhesive layer １ T is the ratio of １ / T ２ The metal foil with a carrier according to any one of claims 1 to 5, wherein the value of the tensile strength is 0.03 or more and 400 or less.

7. The metal foil with a carrier according to any one of claims 1 to 6, wherein the carrier is made of glass, silicon, or ceramics.

8. The thickness T of the metal layer ３ The metal foil with a carrier according to any one of claims 1 to 7, wherein the average particle size is 10 nm or more and 1000 nm or less.

Images