WO2021039759A1

WO2021039759A1 - Carrier-layer-included metal laminate base material and method for producing same, metal laminate base material and method for producing same, and printed wiring board

Info

Publication number: WO2021039759A1
Application number: PCT/JP2020/031951
Authority: WO
Inventors: 南部　光司; 橋本　裕介; 哲平黒川; 功太貞木; 貴文畠田
Original assignee: 東洋鋼鈑株式会社
Priority date: 2019-08-26
Filing date: 2020-08-25
Publication date: 2021-03-04
Also published as: CN114342571A; KR20220053602A

Abstract

The purpose of the present invention is to provide a carrier-layer-included metal laminate base material in which the high adhesion between an ultra-thin metal layer and a low-dielectric film is secured while maintaining the low adhesion between a carrier layer and the ultra-thin metal layer.　A carrier-layer-included metal laminate base material 1A which comprises a low-dielectric film 20 and a three-layered carrier-layer-included metal foil 10 laminated on one surface of the low-dielectric film 20 and comprising a carrier layer 11, a release layer 12 and an ultra-thin metal layer 13, the carrier-layer-included metal laminate base material 1A being characterized in that the bonding strength between the ultra-thin metal layer 13 and the low-dielectric film 20 is larger than the peel strength between the carrier layer 11 and the ultra-thin metal layer 13.

Description

Metal laminated base material with carrier layer and its manufacturing method, metal laminated base material and its manufacturing method, and printed wiring board

The present invention relates to a metal laminated base material with a carrier layer and a manufacturing method thereof, a metal laminated base material and a manufacturing method thereof, and a printed wiring board.

Conventionally, a metal foil with a carrier layer is known as a member for forming fine wiring (fine pitch). This metal foil with a carrier layer is a laminate of a peelable carrier layer and an ultrathin metal layer, and is laminated with a rigid substrate made of glass epoxy resin or the like to form a metal laminated base material with a carrier layer (metal-clad laminate). ) Is obtained. Further, instead of the rigid substrate, one in which a flexible polymer film is laminated is also known, and is used as a metal laminated substrate for forming a flexible circuit board. In particular, a polymer film using a film of a low dielectric polymer such as a low dielectric constant polyimide is useful for a high frequency circuit in a 5th generation mobile communication system (5G).

According to (Patent Document 1), a copper foil with a carrier having an intermediate layer and an ultrathin copper layer on one surface or both surfaces of the carrier in this order, wherein the ultrathin copper layer is a copper foil. A copper foil in which a primary particle layer containing copper is formed on the surface, and then a secondary particle layer containing a ternary alloy composed of copper, cobalt and nickel is formed on the primary particle layer, and the JISZ8730 is formed. With a carrier such as a copper foil for high-frequency circuits having a color difference Δa * value of 4.0 or less and a color difference Δb * value of 3.5 or less when measuring the color difference of the roughened surface in the described color difference system. Copper foil is disclosed. Further, (Patent Document 1) also describes a copper-clad laminate with a carrier in which a rigid substrate such as a paper-based phenol resin or a polymer film such as a liquid crystal polymer (LCP) is laminated with the copper foil with a carrier. Has been done.

Japanese Unexamined Patent Publication No. 2014-224318

In the above (Patent Document 1), when the copper foil with a carrier and the rigid substrate are bonded together, a prepreg obtained by impregnating a base material such as a glass cloth with a resin and curing the resin to a semi-cured state is prepared, and the copper foil is prepared. Is performed by superimposing the above on the prepreg and heating and pressurizing. Further, when a polymer film is used instead of the rigid substrate, copper foil is laminated and bonded (thermocompression bonded) to a base material such as a liquid crystal polymer under high temperature and high pressure.

However, in particular, when a metal foil with a carrier is thermocompression bonded to a low dielectric film such as a liquid crystal polymer, polyethylene fluoride, or low dielectric constant polyimide suitable for high frequency circuit applications, various characteristics such as the melting point of the low dielectric film are obtained. In consideration of the above, the thermocompression bonding temperature must be 280 ° C. or higher, or 300 ° C. or higher. In such a temperature range, the release layer between the carrier layer and the ultrathin metal layer is deteriorated, and the carrier's temperature is changed. There was a problem that the peelability was impaired. On the other hand, if the thermocompression bonding temperature is lowered in order to maintain the peelability, there is a problem that the adhesion between the ultrathin metal layer and the low-dielectric film is lowered. Therefore, it has been difficult in the past to maintain both the peelability (low adhesion) between the carrier and the ultrathin metal layer and to secure the high adhesion between the ultrathin metal layer and the low-dielectric film.

Therefore, the present invention provides a metal laminated base material with a carrier layer, which ensures high adhesion between the ultrathin metal layer and the low-dielectric film while maintaining low adhesion between the carrier layer and the ultrathin metal layer. It is an object of the present invention to provide the manufacturing method. Another object of the present invention is to provide a metal laminated base material in which a low-dielectric film and an ultrathin metal layer are laminated, and a method for producing the same. Another object of the present invention is to provide a printed wiring board obtained from the above-mentioned metal laminated substrate and suitably used for a high frequency circuit.

As a result of diligent studies by the present inventors, a specific joining method was adopted when laminating a low-dielectric film and a metal foil with a carrier layer including a carrier layer, a release layer and an ultrathin metal layer. We have found that the above problems can be solved by controlling the bonding strength between the ultrathin metal layer and the low dielectric film and the peeling strength between the carrier layer and the ultrathin metal layer, respectively, and completed the invention. That is, the gist of the present invention is as follows.

(1) A metal laminated base material with a carrier layer in which a metal foil with a carrier layer including at least three layers including a carrier layer, a release layer and an ultrathin metal layer is laminated on at least one surface of a low-dielectric film. hand,
A metal laminated base material with a carrier layer in which the bonding strength between the ultrathin metal layer and the low-dielectric film is greater than the peel strength between the carrier layer and the ultrathin metal layer.
(2) The metal laminated base material with a carrier layer according to (1) above, which has at least one intermediate layer containing a metal between the low-dielectric film and the ultrathin metal layer.
(3) In (2) above, the intermediate layer contains any one metal selected from the group consisting of copper, iron, nickel, zinc, chromium, cobalt, titanium, tin, platinum, silver and gold or an alloy thereof. The described metal laminated base material.
(4) Any one of the above (1) to (3), wherein the low-dielectric film is a film of a low-dielectric polymer selected from the group consisting of a liquid crystal polymer, polyethylene fluoride, polyamide and a low dielectric constant polyimide. The metal laminated substrate with a carrier layer described in 1.
(5) The metal laminate with a carrier layer according to any one of (1) to (4) above, wherein the peel strength between the carrier layer and the ultrathin metal layer is 0.15 N / cm or more and 0.5 N / cm or less. Base material.
(6) The metal laminated base material with a carrier layer according to any one of (1) to (5) above, wherein the bonding strength between the ultrathin metal layer and the low-dielectric film is 2.0 N / cm or more.
(7) The metal laminated base material with a carrier layer according to any one of (1) to (6) above, wherein the release layer is an organic release layer or an inorganic release layer.
(8) The metal laminated base material with a carrier layer according to any one of (1) to (7) above, wherein the thickness of the ultrathin metal layer is 0.5 μm or more and 10 μm or less.
(9) The method for producing a metal laminated base material with a carrier layer according to (2) above.
A step of preparing a low-dielectric film and a metal foil with a carrier layer including at least three layers including a carrier layer, a release layer and an ultrathin metal layer, and a step of preparing the metal foil.
A step of activating at least one surface of the low-dielectric film by sputtering etching and then sputtering a film of an intermediate layer containing a metal on the surface.
A step of activating the surface of the intermediate layer by sputter etching and
A step of activating the surface of the ultrathin metal layer by sputter etching and
A step of rolling and joining the activated surfaces at a rolling reduction of 0 to 30%,
A method for producing a metal laminated base material with a carrier layer.
(10) The metal laminate group with a carrier layer according to (9) above, wherein the low-dielectric film is a film of a low-dielectric polymer selected from the group consisting of a liquid crystal polymer, polyethylene fluoride, polyamide and a low dielectric constant polyimide. Material manufacturing method.
(11) The method for producing a metal laminated base material with a carrier layer according to (9) or (10) above, wherein the heat treatment is performed at 160 ° C. or higher and 300 ° C. or lower after rolling and joining.
(12) An ultra-thin metal layer is laminated on at least one surface of the low-dielectric film via an intermediate layer containing a metal, and the bonding strength between the low-dielectric film and the ultra-thin metal layer is 2.0 N / cm. The above metal laminated base material.
(13) In (12) above, the intermediate layer contains any one metal selected from the group consisting of copper, iron, nickel, zinc, chromium, cobalt, titanium, tin, platinum, silver and gold or an alloy thereof. The described metal laminated base material.
(14) A roughened particle layer containing any one of the metals selected from the group consisting of Cu, Co and Ni or an alloy thereof on the surface of the ultrathin metal layer on the intermediate layer side, and / or Cr, Ni and Zn. The metal laminated base material according to (12) or (13) above, wherein a rust preventive layer containing any one kind of metal selected from the group consisting of or an alloy thereof is laminated.
(15) The metal laminated base material according to any one of (12) to (14) above, wherein the thickness of the ultrathin metal layer is 0.5 μm or more and 10 μm or less.
(16) A method for producing a metal laminated base material in which an ultrathin metal layer is laminated on at least one surface of a low-dielectric film via an intermediate layer containing a metal.
The method for producing a metal laminated base material, which comprises a step of peeling off the carrier layer in the metal laminated base material with a carrier layer according to the above (2).
(17) A printed wiring board in which a circuit is formed on an intermediate layer and an ultrathin metal layer in the metal laminated base material according to any one of (12) to (15) above.
This specification includes the disclosure contents of Japanese Patent Application Nos. 2019-154167 and 2020-0133319, which are the basis of the priority of the present application.

According to the present invention, in a metal laminated base material with a carrier layer, maintenance of low adhesion between the carrier layer and the ultrathin metal layer and ensuring high adhesion between the ultrathin metal layer and the low dielectric film are ensured. Can be compatible with each other. Further, it is possible to obtain a metal laminated base material in which a low-dielectric film and an ultrathin metal layer are laminated. This metal laminated base material is suitably used for high frequency circuits.

It is sectional drawing of the metal laminated base material with a carrier layer which concerns on 1st Embodiment of this invention. It is sectional drawing of the metal laminated base material with a carrier layer which concerns on 2nd Embodiment of this invention. It is a figure which shows the manufacturing process of the metal laminated base material with a carrier layer which concerns on 2nd Embodiment of this invention. It is a figure which shows the manufacturing process of the metal laminated base material with a carrier layer which concerns on 2nd Embodiment of this invention. It is a figure which shows the manufacturing process of the metal laminated base material which concerns on one Embodiment of this invention. 6 is a scanning electron microscope (SEM) image of each peeled surface of the metal laminated base material with a carrier layer of Example 5 when peeled between the ultrathin copper layer and the low-dielectric film.

Hereinafter, the present invention will be described in detail.
FIG. 1 shows a cross section of a metal laminated base material with a carrier layer according to the first embodiment of the present invention. In the metal laminated base material 1A with a carrier layer shown in FIG. 1, a metal foil 10 with a carrier layer composed of a carrier layer 11, a release layer 12, and an ultrathin metal layer 13 and a low-dielectric film 20 are laminated in this order. It is roughly configured.

Although not shown in FIG. 1, a roughened particle layer, a rust preventive layer, a treated layer with a silane coupling agent, and the like are laminated on the surface of the ultrathin metal layer 13 on the low-dielectric film 20 side. You may. As for these layers, any one kind of layer may be laminated, or a plurality of kinds of layers may be laminated. The roughened particle layer can contain, for example, any kind of metal selected from the group consisting of Cu, Co and Ni, or an alloy thereof. Specific examples thereof include a cobalt-nickel alloy plating layer and a copper-cobalt-nickel alloy plating layer. Further, the rust preventive layer may contain, for example, any kind of metal selected from the group consisting of Cr, Ni and Zn, or an alloy thereof. Specific examples thereof include a coating treatment of chromium oxide, a coating treatment of a mixture of chromium oxide and zinc / zinc oxide, and a Ni plating layer. Further, examples of the silane coupling agent include, but are not limited to, olefin-based silanes, epoxy-based silanes, acrylic-based silanes, amino-based silanes, and mercapto-based silanes. The silane coupling agent can be applied by appropriately using a method such as spraying, coating with a coater, or dipping.

The carrier layer 11 has a sheet shape, and functions as a supporting material or a protective layer for preventing wrinkles and breakage in the metal laminated base material 1A with the carrier layer and scratches on the ultrathin metal layer 13. .. Examples of the carrier layer 11 include foils or plates made of copper, aluminum, nickel, alloys thereof (stainless steel, brass, etc.), resins having a metal coated on the surface, and the like. A copper foil is preferable.

The thickness of the carrier layer 11 is not particularly limited, and is appropriately set according to desired characteristics such as flexibility. Specifically, it is preferably about 10 μm or more and 100 μm or less. If the thickness is too thin, the handleability of the metal foil 10 with a carrier layer may be impaired, which is not preferable. That is, it may be deformed during handling, causing wrinkles or cracks in the ultrathin metal layer 13. Further, if the carrier layer 11 is too thick, it has excessive rigidity as a supporting material and may be difficult to peel off from the ultrathin metal layer 13, which is not preferable. Further, the cost of producing the metal leaf 10 with a carrier layer also increases.

The release layer 12 reduces the release strength of the carrier layer 11, and when the metal foil 10 with the carrier layer is heated when it is bonded to the low-dielectric film 20, it is between the carrier layer 11 and the ultrathin metal layer 13. It also has a function of suppressing mutual diffusion that may occur in. The release layer 12 may be either an organic release layer or an inorganic release layer, and examples of the components used in the organic release layer include nitrogen-containing organic compounds, sulfur-containing organic compounds, and carboxylic acids. Be done. Examples of the nitrogen-containing organic compound include a triazole compound and an imidazole compound. Examples of triazole compounds include 1,2,3-benzotriazole, carboxybenzotriazole, N', N'-bis (benzotriazolylmethyl) urea, 1H-1,2,4-triazole and 3-amino-. Examples thereof include 1H-1,2,4-triazole. Examples of the sulfur-containing organic compound include mercaptobenzothiazole, thiothianulic acid, 2-benzimidazole thiol and the like. Examples of carboxylic acids include monocarboxylic acids and dicarboxylic acids. Examples of the components used in the inorganic release layer include Ni, Mo, Co, Cr, Fe, Ti, W, P, Zn, and a chromate-treated film. The release layer 12 can be formed by bringing the component-containing solution of the release layer 12 into contact with the surface of the carrier layer 11 and fixing the component of the release layer 12 to the surface of the carrier layer 11. When the carrier layer 11 is brought into contact with the component-containing solution of the release layer 12, this contact may be performed by immersion in the release layer component-containing solution, spraying the release layer component-containing solution, flowing down the release layer component-containing solution, or the like. After that, it can be fixed by drying or the like. In addition, a method of forming a film of the components of the release layer 12 by a vapor phase method such as vapor deposition or sputtering can also be adopted.

The thickness of the release layer 12 is typically 1 nm or more and 1 μm or less, preferably 5 nm or more and 500 nm or less, but is not limited thereto. If the thickness of the peeling layer 12 is too thin, there is a problem that the peeling layer 12 cannot be sufficiently separated from the ultrathin metal layer 13 and the peeling is poor. Further, if the thickness is too large, peeling is possible, but the manufacturing cost is high, so that the balance is appropriately set.

The metal constituting the ultrathin metal layer 13 can be appropriately selected according to the application of the metal laminated base material 1A with a carrier layer and the desired characteristics. Specific examples thereof include copper, iron, nickel, zinc, tin, chromium, gold, silver, platinum, cobalt, titanium and alloys based on any of these. In particular, it is preferably a layer of copper or a copper alloy. By rolling and joining these metals with the low-dielectric film 20, for example, a flexible substrate for forming fine wiring can be obtained.

The thickness of the ultrathin metal layer 13 is 0.5 μm or more and 10 μm or less. It is preferably 1 μm or more and 7 μm or less. Here, for the thickness of the ultrathin metal layer 13, an optical micrograph of a cross section of the metal laminated base material 1A with a carrier layer is acquired, and the thickness of the ultrathin metal layer 13 at any 10 points is measured in the optical micrograph. , The average value of the obtained values.

The method for producing such an ultrathin metal layer 13 is not particularly limited, but a release layer can be obtained by a wet film forming method such as an electroless plating method or an electrolytic plating method, a dry film forming method such as sputtering or chemical vapor deposition, or a combination thereof. It can be formed on the twelve.

In the present embodiment, when the bonding strength between the ultra-thin metal layer 13 and the low-dielectric film 20 and the peel strength between the carrier layer 11 and the ultra-thin metal layer 13 are compared, the ultra-thin metal layer 13 and the low-dielectric film 20 are compared. The joint strength of is greater. As a result, when the carrier layer 11 is peeled from the ultra-thin metal layer 13, the ultra-thin metal layer 13 can be peeled off without causing wrinkles or tears. However, if the value of the bonding strength of the ultrathin metal layer 13 and the low dielectric film 20 and the value of the peel strength of the carrier layer 11 and the ultrathin metal layer 13 are too close, the value of the ultrathin metal layer 13 is practically low. Since it may be difficult to peel off the carrier layer 11 without affecting the interface with the dielectric film 20, the bonding strength between the ultrathin metal layer 13 and the low dielectric film 20 and the carrier layer 11 and the electrode The difference from the peel strength of the thin metal layer 13 is preferably 0.25 N / cm or more. It is more preferably 0.5 N / cm or more, and most preferably 1.5 N / cm or more. Specific values of the bonding strength between the ultrathin metal layer 13 and the low dielectric film 20 and the peel strength between the carrier layer 11 and the ultrathin metal layer 13 include the bonding strength between the ultrathin metal layer 13 and the low dielectric film 20. However, it is preferably 2.0 N / cm or more. The peel strength of the carrier layer 11 and the ultrathin metal layer 13 may be greater than 0, preferably 0.5 N / cm or less, but in a region of less than about 0.05 N / cm, the material to be peeled off ( Due to the influence of the rigidity of the carrier layer 11, the ultrathin metal layer 13, the low dielectric film 20, other rust preventive layer, etc.), accurate peel strength may not be measured. The peel strength between the carrier layer 11 and the ultrathin metal layer 13 is preferably in the range of 0.15 N / cm or more and 0.5 N / cm or less. In order to measure the value of the bonding strength, first, a test piece having a width of 1 cm is prepared from the metal laminated base material 1A with a carrier layer. Then, after removing the carrier layer 11, the surface of the ultrathin metal layer 13 is electroplated (when the ultrathin metal layer 13 is copper, for example, copper plating), and the surface of the low dielectric film 20 is about 10 to 20 μm thick. A metal layer (including an ultrathin metal layer 13) is formed. Then, after partially peeling the metal layer having a thickness of about 10 to 20 μm and the low-dielectric film 20, the low-dielectric film 20 is fixed to the support, and the metal layer having a thickness of about 10 to 20 μm is formed into the low-dielectric film. Pull in the 90 ° direction with respect to 20. The force required for peeling at that time is used as the joint strength (unit: N / cm). Further, in order to measure the peel strength, first, a test piece having a width of 1 cm is prepared from the metal laminated base material 1A with a carrier layer. After partially peeling off the carrier layer 11, the low-dielectric film 20 including the ultra-thin metal layer 13 is fixed to the support, and the carrier layer 11 is 90 ° in the direction of the low-dielectric film 20 including the ultra-thin metal layer 13. Pull to. The force required for peeling at that time is defined as the peel strength (unit: N / cm).

In the present specification, the term "bonding strength between the ultrathin metal layer and the low dielectric film" refers to the bonding strength when the ultrathin metal layer and the low dielectric film are peeled off at the interface, and also the ultrathin metal layer. It also means the bonding strength when the inside of the film is broken and peeled off, and the bonding strength when the inside of the low dielectric film is broken and peeled off, and further, as described above, in the ultrathin metal layer. When a roughened particle layer, a rust preventive layer, a treated layer with a silane coupling agent, etc. (collectively referred to as "treated layer") are laminated on the surface of the low dielectric film side, the ultrathin metal layer and the treated layer It also means the bonding strength when peeling at the interface with, the bonding strength when peeling at the interface between the treated layer and the low dielectric film, and the bonding strength when peeling due to the inside of the treated layer being destroyed. To do. Further, when a metal-containing intermediate layer 30 is provided between the low dielectric film 20 and the ultrathin metal layer 13 as in the metal laminated base material with a carrier layer (FIG. 2) according to the second embodiment described later. "The bonding strength between the ultra-thin metal layer and the low-dielectric film" is the bonding strength when the inside of the ultra-thin metal layer is destroyed and peeled off, and the ultra-thin metal layer (treated if a treated layer exists). Bonding strength when peeling at the interface between the layer) and the intermediate layer, bonding strength when peeling at the interface between the intermediate layer and the low dielectric film, bonding strength when peeling due to destruction of the inside of the intermediate layer , And the bonding strength when the inside of the low-dielectric film is broken and peeled off.

The low-dielectric film 20 is laminated on the ultra-thin metal layer 13. As the material of the low-dielectric film 20, any low-dielectric polymer material that can be used as a flexible substrate can be applied. For example, the relative permittivity ε _r is 3.3 or less, and the value of the dielectric loss tangent tan δ is 0. The material is 006 or less, but is not limited to this. Specifically, it is appropriately selected from materials such as liquid crystal polymer, polyfluoroethylene (fluorine-based resin such as polytetrafluoroethylene), polyamide, isocyanate compound, polyamideimide, polyimide, low dielectric constant polyimide, polyethylene terephthalate, and polyetherimide. Can be used. A liquid crystal polymer, polyethylene fluoride, polyamide or low dielectric constant polyimide is preferable. The low-dielectric film 20 is a single-layer film or a laminate composed of a plurality of layers, and in the case of a plurality of layers, any one or more of the plurality of layers is the above-mentioned low-dielectric polymer. Any layer made of material may be used. The layers other than the layer made of the low-dielectric polymer material can be made of various conventionally known materials such as epoxy resin. The liquid crystal polymer refers to an aromatic polyester-based resin having a basic structure such as parahydroxybenzoic acid, which exhibits the properties of a liquid crystal in a molten state.

The thickness of the low-dielectric film 20 can be appropriately set according to the application of the metal laminated base material and the like. For example, when used as a flexible printed wiring board, the thickness is preferably 10 μm or more and 150 μm or less, and more preferably 10 μm or more and 120 μm or less. The thickness of the low-dielectric film 20 before bonding can be measured with a micrometer or the like, and refers to the average value of the thickness measured at 10 points randomly selected from the surface of the target low-dielectric film. Further, for the low-dielectric film to be used, it is preferable that the deviation from the average value of the measured values at 10 points is within 10% for all the measured values.

Next, the second embodiment of the present invention will be described. FIG. 2 shows a cross section of the metal laminated base material with a carrier layer according to the second embodiment of the present invention. In the present embodiment, as shown in FIG. 2, an intermediate layer 30 containing a metal is provided between the ultrathin metal layer 13 and the low-dielectric film 20. The intermediate layer 30 may be one layer or two or more layers may be laminated. Examples of the intermediate layer 30 containing a metal include a metal layer provided on the low-dielectric film 20 by thin-film deposition, electroless plating, or sputtering film formation.

Although not shown in FIG. 2, the surface of the ultrathin metal layer 13 on the intermediate layer 30 side has a roughened particle layer and a rust preventive, similar to the metal laminated base material with a carrier layer according to the first embodiment. A rust layer, a layer of a silane coupling agent, and the like may be laminated. As for these layers, any one kind of layer may be laminated, or a plurality of kinds of layers may be laminated. The roughened particle layer can include, but is not limited to, any kind of metal selected from the group consisting of Cu, Co and Ni, or an alloy thereof. Further, the rust preventive layer may contain, for example, any kind of metal selected from the group consisting of Cr, Ni and Zn or an alloy thereof, but is not limited thereto.

The intermediate layer 30 preferably contains any kind of metal selected from the group consisting of copper, iron, nickel, zinc, chromium, cobalt, titanium, tin, platinum, silver and gold or an alloy thereof. In particular, when the ultrathin metal layer 13 is copper or an alloy thereof, the metal constituting the intermediate layer 30 is also preferably an alloy containing copper such as copper or a copper-nickel alloy. When the intermediate layer 30 is, for example, a Cu—Ni alloy, the ratio of Ni to Cu is preferably 10 to 90% in at%. However, it is not limited to this. By providing these intermediate layers 30, it is possible to protect the surface of the ultra-thin metal layer 13 or the low-dielectric film 20 and improve the adhesion between the ultra-thin metal layer 13 and the low-dielectric film 20. However, it is possible to impart a function peculiar to the intermediate layer 30 (for example, a function as an etching stopper layer during etching processing). The thickness of the intermediate layer 30 is not particularly limited as long as it can exhibit functions such as improving adhesion. Specifically, the thickness is preferably 5 nm or more and 200 nm or less, and more preferably 10 nm or more and 100 nm or less.

Next, regarding the method for producing a metal laminated base material with a carrier layer according to the present invention, an intermediate layer 30 containing a metal is provided between the low-dielectric film 20 and the ultrathin metal layer 13, as shown in FIG. A case of manufacturing the metal laminated base material 1B with a carrier layer will be described as an example. In the metal laminated base material 1B with a carrier layer shown in FIG. 2, a metal foil 10 with a carrier layer composed of a carrier layer 11, a release layer 12, and an ultrathin metal layer 13 and a low-dielectric film 20 are prepared, and low-dielectricity is obtained. It can be obtained by providing an intermediate layer 30 containing a metal on the surface of the film 20 and then joining them to each other by various methods such as cold rolling bonding and surface activation bonding to bring the layers into close contact with each other. .. The bonding and / or heat treatment under high pressure during the production of the metal laminated base material 1B with a carrier layer significantly changes the structure of each layer of the metal laminated base material 1B with a carrier layer before and after joining and / or before and after the heat treatment. Since the characteristics of the metal laminated base material 1B with a carrier layer may be impaired, it is preferable to select bonding / heat treatment conditions that can avoid such structural changes.

A preferred embodiment as a method for producing the metal laminated base material 1B with a carrier layer will be described with reference to FIGS. 3A and 3B. First, as shown in FIG. 3A, after the surface 20a of the low-dielectric film 20 is activated by sputter etching ((a) in FIG. 3A), the intermediate layer 30 containing a metal on the surface 20a of the low-dielectric film 20 Is sputtered and formed. The conditions for performing the sputter film formation can be appropriately set according to the metal species constituting the intermediate layer 30 and the thickness of the intermediate layer 30.

Next, as shown in FIG. 3B, the surface 30a of the intermediate layer 30 is activated by sputtering etching, and the surface 13a of the ultrathin metal layer 13 in the metal foil 10 with a carrier layer is activated by sputtering etching, and these activated surfaces are used. By rolling and joining each other ((c) in FIG. 3B), the metal laminated base material 1B with a carrier layer can be manufactured ((d) in FIG. 3B). When the surface 13a of the ultrathin metal layer 13 contains a roughened particle layer or a rust preventive layer, the surface of the roughened particle layer or the rust preventive layer is activated by sputter etching. At that time, the roughened particle layer and the rust preventive layer may be completely removed by sputter etching, or may remain without being removed. The reduction ratio at the time of rolling and joining is 0 to 30%. It is preferably 0 to 15%. Since the above-mentioned surface-activated bonding method can reduce the reduction rate, it is possible to perform bonding while maintaining the function (low adhesion) of the release layer 12, and wrinkles, cracks, etc. occur. The ultra-thin metal layer 13 having excellent thickness accuracy can be formed without any problem. Further, since the waviness at the interface between the ultrathin metal layer 13 and the intermediate layer 30 and the low-dielectric film 20 can be reduced, a circuit is formed by performing pattern etching on the ultrathin metal layer 13 and the intermediate layer 30. In addition, since the thickness accuracy is excellent, a precise circuit can be obtained.

The surface 30a of the intermediate layer 30 or the surface 13a of the ultrathin metal layer 13 before being activated by sputter etching is subjected to Ni plating, chromate treatment, or silane, if necessary, in order to prevent oxidation and improve adhesion. It may be treated with a coupling agent or the like. Further, the surface 13a of the ultrathin metal layer 13 can be roughened as necessary in order to improve the adhesion with the intermediate layer 30.

For the sputter etching treatment, for example, a low-dielectric film 20 provided with a carrier layer-attached metal foil 10 or an intermediate layer 30 to be bonded is prepared as a long coil having a width of 100 mm to 600 mm, and the carrier layer-attached metal foil 10 or low-dielectric The joint surface of the sex film 20 is used as one electrode grounded to the ground, and an AC of 1 MHz to 50 MHz is applied between the electrode and the other electrode supported by insulation to generate a glow discharge, and the glow discharge is generated in the plasma. The area of the exposed electrode can be set to 1/3 or less of the area of the other electrode. During the sputter etching process, the grounded electrode is in the form of a cooling roll to prevent the temperature of the conveyed material from rising.

In the sputter etching process, the surface to be bonded to the metal foil 10 with a carrier layer or the low-dielectric film 20 is sputtered with an inert gas under vacuum to completely remove adsorbents on the surface and the oxide layer on the surface. Remove some or all of. It is preferable to completely remove the copper oxide layer. As the inert gas, argon, neon, xenon, krypton and the like, and a mixed gas containing at least one of these can be applied. Although it depends on the type of metal, the adsorbent on the surface of the ultrathin metal layer 13 or the intermediate layer 30 can be completely removed with an etching amount of about 1 nm, and in particular, the copper oxide layer is usually 5 nm to 12 nm (usually 5 nm to 12 nm). It can be removed by (converted to _{SiO 2).}

The processing conditions for sputter etching can be appropriately set according to the type of the ultrathin metal layer 13 or the intermediate layer 30 and the like. For example, it can be performed under vacuum at a plasma output of 100 W to 10 kW and a line speed of 0.5 m / min to 30 m / min. The degree of vacuum at this time is preferably high in order to prevent re-adsorbed substances on the surface, but may be, for example, 1 × 10 ^-5 Pa to 10 Pa.

The surfaces of the ultrathin metal layer 13 and the intermediate layer 30 that have undergone sputtering etching can be pressure-welded to each other by roll pressure welding. The rolling wire load for roll pressure welding is not particularly limited, and can be set, for example, in the range of 0.1 tf / cm to 10 tf / cm. However, when the thickness of the low-dielectric film 20 provided with the metal foil 10 with a carrier layer or the intermediate layer 30 before joining is large, it is necessary to increase the rolling wire load in order to secure the pressure at the time of joining. In some cases, it is not limited to this numerical range. On the other hand, if the rolling wire load is too high, not only the surface layer of the ultrathin metal layer 13 or the intermediate layer 30 but also the bonding interface is easily deformed, so that the thickness accuracy of each layer in the metal laminated base material 1B with a carrier layer is high. May decrease. Further, if the rolling wire load is high, the machining strain applied at the time of joining may increase.

The reduction rate at the time of pressure welding is 30% or less, preferably 8% or less, and more preferably 6% or less. Since the thickness does not have to change before and after the pressure welding, the lower limit of the reduction rate is 0%.

In the bonding by roll pressure welding, in order to prevent the bonding strength between the two from being lowered due to the re-adsorption of oxygen on the surface of the ultrathin metal layer 13 or the intermediate layer 30, in a non-oxidizing atmosphere, for example, in a vacuum or in Ar, etc. It is preferable to carry out in an active gas atmosphere.

Further, the metal laminated base material 1B with a carrier layer obtained by pressure welding can be further heat-treated if necessary. By the heat treatment, the strain of the ultrathin metal layer 13 or the intermediate layer 30 is removed, and the adhesion between the layers can be improved. When this heat treatment is performed at a high temperature for a long time, blister is generated in the carrier layer 11 starting from the peeling layer 12, and the carrier layer 11 may be peeled off from the blister, or conversely, the carrier layer 11 and the ultrathin metal layer. Adhesion with 13 may be enhanced by mutual diffusion or the like, and it may be difficult to peel off the carrier layer 11. Further, depending on the combination of the ultrathin metal layer 13 and the intermediate layer 30, an intermetallic compound is formed at the interface, and the adhesion (bonding strength) tends to decrease. Therefore, the above heat treatment is performed at a temperature of 160 ° C. or higher and 300 ° C. or lower. More preferably, it is 180 ° C. or higher and 290 ° C. or lower. Alternatively, it is preferable not to perform heat treatment after rolling and joining. After the carrier layer 11 is peeled off and removed from the metal laminated base material 1B with a carrier layer after bonding, heat treatment is performed in a temperature range in which an intermetallic compound is not generated at the interface between the ultrathin metal layer 13 and the intermediate layer 30. May be done.

Next, the metal laminated base material and the manufacturing method thereof according to the present invention will be described. FIG. 4 is a diagram showing a manufacturing process of a metal laminated base material according to an embodiment of the present invention. The metal laminated base material 2 shown in FIG. 4 is roughly configured by laminating an ultrathin metal layer 13 on one surface of a low-dielectric film 20 via an intermediate layer 30 containing a metal. The metal laminated base material 2 is the same as the metal laminated base material 1B with a carrier layer shown in FIG. 2 except that it does not have the carrier layer 11 and the release layer 12, and the configuration of each layer is the metal laminated base material 1B with a carrier layer. It is the same as the composition of each layer in. The metal laminated base material 2 can be obtained from the metal laminated base material 1B with a carrier layer. That is, as shown in FIG. 4, the metal laminated base material 1B with a carrier layer is prepared ((a) of FIG. 4), and the carrier layer 11 in the metal laminated base material 1B with a carrier layer is peeled off together with the release layer 12. ((B) in FIG. 4), a metal laminated base material 2 having a three-layer structure can be obtained ((c) in FIG. 4).

The manufactured metal laminated base material 2 has, for example, an ultrathin metal layer 13 having a thickness of 0.5 μm or more and 10 μm or less, and is a metal laminated base material (metal-clad) for producing a flexible circuit board. It can be used as a laminated board). In the metal laminated base material of the present invention, an additional metal layer was laminated on the surface of the ultrathin metal layer 13 opposite to the low dielectric film by electroless plating, electrolytic plating (for example, copper plating) or the like. It includes morphology.

A printed wiring board on which a fine circuit is formed can be obtained by using the metal laminated base material 2. In the process of forming the circuit, the additional metal layer may be formed only on the circuit portion. Specifically, a printed wiring board can be obtained by appropriately using a conventionally known method such as a modified semi-additive method (MSAP method) or a semi-additive method (SAP method). For example, a electrode in a metal laminated substrate 2 can be obtained. The non-circuit part on the thin metal layer 13 is masked, the unmasked part is copper-plated to form an additional metal layer, the mask is removed, and the ultra-thin metal layer 13 hidden by the mask is etched. A printed wiring board can be manufactured by removing it. The "printed wiring board" in the present invention includes not only a laminated body in which a circuit is formed but also a board in which electronic components such as ICs are mounted after the circuit is formed.

In the embodiment of the metal laminated base material 1A with a carrier layer in FIG. 1, the metal laminated base material 1B with a carrier layer in FIG. 2, and the metal laminated base material 2 in FIG. 4, carriers are formed on one surface of the low dielectric film 20. Although the case where the layered metal foil 10 or the ultrathin metal layer 13 is laminated has been described, the present invention is not limited to this. That is, if necessary, the intermediate layer 30, the ultrathin metal layer 13, the release layer 12, and the carrier layer 11 may be provided on both surfaces of the low-dielectric film 20. By using a metal laminated base material with a carrier layer in which each of these layers is provided on both sides of the low-dielectric film 20, a flexible printed wiring board in which circuits are formed on both sides of the low-dielectric film 20 can be obtained. ..

Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples, but the present invention is not limited to these Examples.

(Example 1)
First, as a metal foil with a carrier layer, a carrier layer having a thickness of 18 μm made of copper, an ultrathin copper layer having a thickness of 1.5 μm via a release layer (organic release layer), and a roughened particle layer and rust preventive on the surface thereof. A copper foil with a carrier layer provided with a layer (MT18FL manufactured by Mitsui Metal Mining Co., Ltd.) and a liquid crystal polymer (LCP) film having a thickness of 25 μm were prepared as a low dielectric film. After activating the surface of the LCP film by sputtering etching, an intermediate layer (thickness 40 nm) made of copper was formed by sputtering film formation. Then, the surfaces of the ultrathin copper layer and the intermediate layer were rolled and joined to produce a target metal laminated base material with a carrier layer. The linear load at the time of pressure welding is 1.5 tf / cm, and the reduction rate by surface activation bonding is 2.2%. After the rolling joint, heat treatment was performed at 240 ° C.

(Example 2)
As a metal foil with a carrier layer, a carrier layer having a thickness of 18 μm made of copper is provided with an ultrathin copper layer having a thickness of 1.5 μm via a release layer (organic release layer), and a roughened particle layer and a rust preventive layer on the surface thereof. A provided copper foil with a carrier layer (MT18FL manufactured by Mitsui Metal Mining Co., Ltd.) was used. Further, as a low-dielectric film, an LCP film having a thickness of 100 μm was used, and after the surface was activated by sputtering etching, an intermediate layer (thickness 40 nm) made of copper was formed by sputtering film formation. Then, the surfaces of the ultrathin copper layer and the intermediate layer were rolled and joined, and then heat treatment was performed to produce a metal laminated base material with a carrier layer. The joining conditions are as shown in Table 1. The reduction rate due to surface activation bonding is 2.5%.

(Examples 3 and 4)
A metal laminated base material with a carrier layer was produced in the same manner as in Example 2 except that the joining conditions were changed as shown in Table 1. The reduction rates in Examples 3 and 4 are 2.5% and 3.5%, respectively.

(Example 5)
As the low-dielectric film and the intermediate layer, an intermediate layer (thickness 40 nm) made of copper was formed on the surface of an LCP film having a thickness of 25 μm by sputter film formation as in Example 1, and the bonding conditions were further described in Table 1. A metal laminated base material with a carrier layer was produced in the same manner as in Example 2 except that the changes were made as shown in. The reduction rate is 2.2%.

(Example 6)
As a metal foil with a carrier layer, a carrier layer having a thickness of 18 μm made of copper, an ultrathin copper layer having a thickness of 3.0 μm via a release layer (inorganic release layer), and a roughened particle layer and a rust preventive layer on the surface thereof. A metal laminated group with a carrier layer was used in the same manner as in Example 5, except that the provided copper foil with a carrier layer (JXUT-III manufactured by JX Nippon Mining & Metals Co., Ltd.) was used and the joining conditions were changed as shown in Table 1. Manufactured the material. The reduction rate is 4.3%.

(Example 7)
As the low-dielectric film and the intermediate layer, except that an intermediate layer (thickness 40 nm) made of copper was formed on the surface of a low-dielectric polyimide (modified polyimide, MPI) film having a thickness of 25 μm by sputter film formation. A metal laminated base material with a carrier layer was produced in the same manner as in Example 4. The reduction rate is 2.2%.

(Example 8)
As a metal foil with a carrier layer, a carrier layer having a thickness of 18 μm made of copper, an ultrathin copper layer having a thickness of 2.0 μm via a release layer (inorganic release layer), and a rust preventive layer only on the surface thereof (roughened particle layer). A metal laminated base material with a carrier layer was produced in the same manner as in Example 6 except that a copper foil with a carrier layer (prototype material 1) provided with (none) was used and the joining conditions were changed as shown in Table 1. did. The reduction rate is 2.2%.

(Example 9)
As a metal foil with a carrier layer, a carrier layer having a thickness of 18 μm made of copper, an ultrathin copper layer having a thickness of 5.0 μm via a release layer (organic release layer), and a rust preventive layer only on the surface thereof (roughened particle layer). A metal laminated base material with a carrier layer was produced in the same manner as in Example 8 except that a copper foil with a carrier layer (prototype material 2) provided with (none) was used and the joining conditions were changed as shown in Table 1. did. The reduction rate is 6.3%.

(Comparative Example 1)
A metal laminated base material with a carrier layer was produced in the same manner as in Example 5 except that the joining conditions were changed as shown in Table 1. The reduction rate is 2.2%.

(Comparative Example 2)
A metal laminated base material with a carrier layer was produced in the same manner as in Example 6 except that the joining conditions were changed as shown in Table 1. The reduction rate is 4.3%.

(Comparative Example 3)
A metal laminated base material with a carrier layer was produced in the same manner as in Example 5 except that the joining conditions were changed as shown in Table 1. The reduction rate is 2.2%.

(Comparative Example 4)
A metal laminated base material with a carrier layer was produced in the same manner as in Example 6 except that the joining conditions were changed as shown in Table 1. The reduction rate is 4.3%.

(Comparative Example 5)
First, as a metal foil with a carrier layer, a carrier layer having a thickness of 18 μm made of copper, an ultrathin copper layer having a thickness of 2.0 μm via a release layer (organic release layer), and a roughened particle layer and rust preventive on the surface thereof. A copper foil with a carrier layer provided with a layer (MT18FL manufactured by Mitsui Metal Mining Co., Ltd.) and a liquid crystal polymer (LCP) film having a thickness of 25 μm were prepared as a low dielectric film. Subsequently, the copper foil with a carrier layer and the LCP film were bonded by thermocompression bonding to produce a metal laminated base material with a carrier layer. The conditions for thermocompression bonding are as shown in Table 2.

(Comparative Examples 6 and 7)
A metal laminated base material with a carrier layer was produced in the same manner as in Comparative Example 5, except that the thermocompression bonding conditions were changed as shown in Table 2.

(Comparative Example 8)
First, as a metal foil with a carrier layer, a carrier layer having a thickness of 18 μm made of copper, an ultrathin copper layer having a thickness of 3.0 μm via a release layer (inorganic release layer), and a roughened particle layer and rust preventive on the surface thereof. A copper foil with a carrier layer provided with a layer (JXUT-III manufactured by JX Nippon Mining & Metals Co., Ltd.) and a liquid crystal polymer (LCP) film having a thickness of 25 μm were prepared as a low dielectric film. Subsequently, the copper foil with a carrier layer and the LCP film were bonded by thermocompression bonding to produce a metal laminated base material with a carrier layer. The conditions for thermocompression bonding are as shown in Table 2.

(Comparative Examples 9 and 10)
A metal laminated base material with a carrier layer was produced in the same manner as in Comparative Example 8 except that the thermocompression bonding conditions were changed as shown in Table 2.

With respect to the metal laminated base material with a carrier layer obtained in Examples 1 to 9 and Comparative Examples 1 to 10, the bonding strength between the ultrathin copper layer and the low dielectric film, the peel strength between the carrier layer and the ultrathin copper layer, and the total The thickness was measured. The measurement results are shown in Table 3.

As shown in Tables 1 and 3, when the heat treatment temperature is high (Comparative Examples 1 and 2) and when the heat treatment temperature is low (Comparative Examples 3 and 4), the adhesion between the carrier layer and the ultrathin copper layer is low. It was not possible to achieve both properties and high adhesion between the ultrathin copper layer and the low-dielectric film.

Further, as shown in Tables 2 and 3, when the copper foil with a carrier layer and the low-dielectric film are bonded by thermocompression bonding, the low adhesion between the carrier layer and the ultra-thin copper layer and the ultra-thin copper are obtained. It was not possible to achieve both high adhesion between the layer and the low-dielectric film. In particular, in Comparative Examples 6, 7, 9 and 10, the low-dielectric film was brittle and deteriorated, and was unsuitable as a metal laminated base material for forming a circuit. Further, in Comparative Example 10, the carrier layer and the ultrathin copper layer could not be separated.

Further, each peeled surface after measuring the bonding strength in Example 5 was observed using a scanning electron microscope (SEM) and surface element analysis by EDX was performed. A scanning electron microscope image is shown in FIG. As a result of the analysis, it was confirmed that copper did not adhere to the peeled surface on the LCP side of Example 5. In addition, since some of the coagulated and fractured LCPs are attached to the ultrathin copper layer side (the peeled surface is an intermediate layer), the peeling is caused by both the internal fracture of the LCP and the interfacial peeling of the intermediate layer and the LCP. It became clear.

(Examples 10 to 16)
By removing the carrier layer from the metal laminated base material with the carrier layer obtained in Examples 1 to 7, an ultrathin copper layer having a thickness of 1.5 μm to 3.0 μm including a roughened particle layer and a rust preventive layer is provided. A metal laminated base material was produced.

(Examples 17 and 18)
By removing the carrier layer from the metal laminated base material with the carrier layer obtained in Examples 8 and 9, a pole having a thickness of 2.0 μm to 5.0 μm including only the rust preventive layer (excluding the roughened particle layer). A metal laminated base material having a thin copper layer was produced.

With respect to the obtained metal laminated base materials of Examples 10 to 18, the bonding strength, total thickness, and thickness of the ultrathin copper layer between the ultrathin copper layer and the low-dielectric film were measured. The measurement results are shown in Table 4.

The metal laminated base material of Examples 10 to 16 is composed of an ultrathin copper layer, a roughened particle layer, a rust preventive layer, an intermediate layer (copper) and an LCP or MPI film, and Examples 17 and 18 The metal laminated base material of is composed of an ultrathin copper layer, a rust preventive layer, an intermediate layer (copper) and an LCP. For these metal laminated substrates, the distribution state (Dept Profile) of elements in the depth direction (Depts Profile) measurement by glow discharge emission spectroscopy (GDS) and Auger electron spectroscopy (AES) and cross-sectional observation by transmission electron microscope (TEM) It is possible to specify the laminated state of each layer by using.

Further, a circuit pattern is formed on an ultrathin copper layer in a metal laminated base material by a resist or the like, and a fine circuit is formed on a low-dielectric film by a modified semi-additive method (MSAP method) or a semi-additive method (SAP method). Can be formed.

1A Metal laminated base material with carrier layer 1B Metal laminated base material with carrier layer 2 Metal laminated base material 10 Metal foil with carrier layer 11 Carrier layer 12 Peeling layer 13 Ultra-thin metal layer 13a Surface of ultra-thin metal layer 20 Low dielectric film 20a Surface of low dielectric film 30 Intermediate layer 30a Surface of intermediate layer All publications, patents and patent applications cited herein are incorporated herein by reference in their entirety.

Claims

A metal laminated base material with a carrier layer in which a metal foil with a carrier layer composed of at least three layers including a carrier layer, a release layer and an ultrathin metal layer is laminated on at least one surface of the low-dielectric film.
A metal laminated base material with a carrier layer in which the bonding strength between the ultrathin metal layer and the low-dielectric film is greater than the peel strength between the carrier layer and the ultrathin metal layer.
The metal laminated base material with a carrier layer according to claim 1, which has one or more intermediate layers containing a metal between the low-dielectric film and the ultrathin metal layer.
The metal laminate according to claim 2, wherein the intermediate layer comprises any one metal selected from the group consisting of copper, iron, nickel, zinc, chromium, cobalt, titanium, tin, platinum, silver and gold or an alloy thereof. Base material.
The carrier layer according to any one of claims 1 to 3, wherein the low-dielectric film is a film of a low-dielectric polymer selected from the group consisting of a liquid crystal polymer, polyfluoroethylene, polyamide and a low dielectric constant polyimide. Metal laminate substrate.
The metal laminated base material with a carrier layer according to any one of claims 1 to 4, wherein the peel strength between the carrier layer and the ultrathin metal layer is 0.15 N / cm or more and 0.5 N / cm or less.
The metal laminated base material with a carrier layer according to any one of claims 1 to 5, wherein the bonding strength between the ultrathin metal layer and the low-dielectric film is 2.0 N / cm or more.
The metal laminated base material with a carrier layer according to any one of claims 1 to 6, wherein the release layer is an organic release layer or an inorganic release layer.
The metal laminated base material with a carrier layer according to any one of claims 1 to 7, wherein the thickness of the ultrathin metal layer is 0.5 μm or more and 10 μm or less.
The method for producing a metal laminated base material with a carrier layer according to claim 2.
A step of preparing a low-dielectric film and a metal foil with a carrier layer including at least three layers including a carrier layer, a release layer and an ultrathin metal layer, and a step of preparing the metal foil.
A step of activating at least one surface of the low-dielectric film by sputtering etching and then sputtering a film of an intermediate layer containing a metal on the surface.
A step of activating the surface of the intermediate layer by sputter etching and
A step of activating the surface of the ultrathin metal layer by sputter etching and
A step of rolling and joining the activated surfaces at a rolling reduction of 0 to 30%,
A method for producing a metal laminated base material with a carrier layer.
The method for producing a metal laminated base material with a carrier layer according to claim 9, wherein the low-dielectric film is a film of a low-dielectric polymer selected from the group consisting of a liquid crystal polymer, polyethylene fluoride, polyamide and a low dielectric constant polyimide. ..
The method for producing a metal laminated base material with a carrier layer according to claim 9 or 10, wherein the heat treatment is performed at 160 ° C. or higher and 300 ° C. or lower after rolling and joining.
An ultra-thin metal layer is laminated on at least one surface of the low-dielectric film via an intermediate layer containing a metal, and the bonding strength between the low-dielectric film and the ultra-thin metal layer is 2.0 N / cm or more. Metal laminated substrate.
The metal laminate according to claim 12, wherein the intermediate layer comprises any one metal selected from the group consisting of copper, iron, nickel, zinc, chromium, cobalt, titanium, tin, platinum, silver and gold or an alloy thereof. Base material.
A roughened particle layer containing any one of the metals selected from the group consisting of Cu, Co and Ni or an alloy thereof on the surface of the ultrathin metal layer on the intermediate layer side, and / or a group consisting of Cr, Ni and Zn. The metal laminated base material according to claim 12 or 13, wherein a rust preventive layer containing any one of the metals selected from the above or an alloy thereof is laminated.
The metal laminated base material according to any one of claims 12 to 14, wherein the thickness of the ultrathin metal layer is 0.5 μm or more and 10 μm or less.
A method for producing a metal laminated base material in which an ultrathin metal layer is laminated on at least one surface of a low-dielectric film via an intermediate layer containing a metal.
The method for producing a metal laminated base material, which comprises a step of peeling off the carrier layer in the metal laminated base material with a carrier layer according to claim 2.
A printed wiring board in which a circuit is formed on an intermediate layer and an ultrathin metal layer in the metal laminated base material according to any one of claims 12 to 15.