JP6471140B2 - Composite metal foil, copper-clad laminate using the composite metal foil, and method for producing the copper-clad laminate - Google Patents

Description

The present invention relates to a composite metal foil, a copper-clad laminate using the composite metal foil, and a method for producing the copper-clad laminate.
Specifically, the composite metal foil can be produced by a simple method of a copper-clad laminate in which an ultrathin copper layer is laminated, and the ultrathin copper layer is extremely thin and dense and hardly causes pinholes. Therefore, if the ultra-thin copper layer is used as a seed layer for the additive method, the seed layer can be removed by etching in a short time, so that etching of the circuit itself can be suppressed and a fine pattern circuit can be formed. If a multilayer substrate is manufactured using a copper-clad laminate made of composite metal foil, the copper layer itself is very thin even if the through-holes and non-through-holes are electrolessly plated and / or electroplated for interlayer connection. The present invention relates to a composite metal foil capable of producing a high-density multilayer substrate while suppressing the entire substrate from becoming thick, a copper-clad laminate using the composite metal foil, and a method for producing the copper-clad laminate.

  Electronic devices that require miniaturization and improved processing speed include semiconductor devices that use printed wiring boards with fine pattern circuits (hereinafter referred to as “fine patterns”) and multilayer printed wiring boards. A package board mounted with high density is mounted.

  Also, a build-up board is used for rewiring for the elements to be mounted, and a fine pattern circuit is also required for the build-up board as the elements are miniaturized.

  Conventionally, the fine pattern circuit and the line-to-line (= space) width (hereinafter referred to as “L / S”) were L / S = 30 μm / 30 μm, but in recent years L / S = 15 μm / 15 μm Furthermore, there is a demand for a circuit with an ultra fine pattern of L / S = 10 μm / 10 μm.

  In general, as a copper clad laminate for forming a fine pattern circuit, a copper clad laminate in which an ultrathin copper foil is laminated to an insulating resin base material (hereinafter referred to as `` base material '') is used. However, when the copper foil is less than 9 μm, there is a problem that wrinkles and cracks are likely to occur when it is laminated to a copper clad laminate.

  Therefore, the surface of the ultra-thin copper foil of the composite metal foil obtained by laminating ultra-thin copper foil on a support (hereinafter referred to as “carrier”) is subjected to a roughening treatment and bonded to a substrate, and then the carrier is peeled off. Thus, a method for producing a copper clad laminate in which ultrathin copper foils are laminated has been developed.

 In addition to using an ultrathin copper foil with a carrier, a copper-clad laminate with an ultrathin copper foil layer can be manufactured by laminating copper foil of 12 μm or less, and thinning the copper foil by half-etching technology, etc. A method of forming an ultrathin copper foil layer has also been developed.

  As a method for forming a fine pattern circuit using a copper-clad laminate having an ultrathin copper foil layer, a subtractive method or an additive method is known.

However, in the subtractive construction method, the conductor (ultra thin copper foil layer) cannot be used as a circuit because it is thin as it is.
If the plating is performed to increase the thickness, the space portion becomes narrow due to the plating grown from the line portion, and as a result, it is difficult to form a fine pattern circuit.

  In the additive method, the thickness of the conductor can be controlled by electrolytic plating. However, the layer consisting of ultrathin copper foil and the roughening treatment on the surface of the ultrathin copper foil becomes the seed layer, so the seed layer is removed in a short time by etching. However, since the circuit is etched even during etching, it is difficult to form a fine pattern circuit.

  If the ultra-thin copper foil layer is made even thinner by half-etching technology, etc., the etching time will be shortened and the etching of the circuit can be suppressed. However, the etching amount of the ultra-thin copper foil layer must be controlled very precisely. In addition, the foil thickness distribution of the ultrathin copper foil is extremely difficult because it requires extremely high accuracy.

  Further, if the ultrathin copper foil itself is made thin, the etching time is shortened, so that etching of the circuit can be suppressed. However, pinholes are easily generated, and the circuit is missing at the pinhole portion. In the fine pattern circuit, if any circuit is missing, the risk of circuit disconnection increases, which is a problem.

  In both subtractive method and additive method, ultrathin copper foil layer is also plated by the process of electroless plating and / or electrolytic plating of through-holes and non-through-holes, which is an indispensable process for interlayer connection in multilayering. As a result, there is a problem in that the entire substrate becomes thick as a result, and density increase is hindered.

  Therefore, a copper-clad laminate having an ultrathin copper layer thinner than an ultrathin copper foil layer, and if the ultrathin copper layer is used as a seed layer for an additive method, the circuit can be removed by etching in a very short time. Can be suitably used for forming fine pattern circuits, and when increasing the number of layers, the increase in overall thickness can be suppressed, producing a high-density multilayer substrate. It is desired to develop a composite metal foil capable of producing a copper clad laminate having an ultrathin copper layer that can be manufactured by a simple method.

JP 2009-246120 A WO2002-024444 JP2013-204065

  Patent Document 1 describes a composite foil with a carrier in which an Fe—Ni alloy layer, a copper or copper alloy layer provided on a carrier foil via a release layer are laminated in this order.

  However, since the composite foil with a carrier described in Patent Document 1 has a release layer laminated on the carrier foil, the heat resistance of the release function is low when bonded to a substrate at high temperature and high pressure, and the carrier foil is at the interface. There is a problem that it does not peel off cleanly.

  In addition, since a roughening layer is provided on the copper or copper alloy layer when pasting to the base material, the seed layer cannot be removed by etching in a short time if the additive layer is used as a seed layer, and even the circuit is etched. Therefore, there is a possibility that a fine pattern circuit cannot be formed.

  In addition, even if the Fe—Ni alloy layer is removed by selective etching of Ni, it cannot be removed cleanly because it is an alloy.

  Patent Document 2 discloses an ultrathin copper foil with a carrier in which a peeling layer, a diffusion prevention layer, and an electrolytic copper plating layer are laminated in this order on the surface of a carrier foil, and a Ni layer is used as the diffusion prevention layer. It is described that it can be.

  However, in the ultrathin copper foil with a carrier described in Patent Document 2, since the release layer is laminated on the carrier foil, similarly to the composite foil with a carrier described in Patent Document 1, the heat resistance of the peeling function is low, and the carrier foil is There is a problem that it does not peel off at the interface.

  In addition, since the Ni layer on the ultrathin copper foil layer is very thin, there is a high possibility that pinholes will occur in the Ni layer. There is a problem that chipping occurs.

  Patent Document 3 discloses a copper foil with a carrier in which a copper foil carrier, an intermediate layer laminated on the copper foil carrier, and an ultrathin copper foil layer laminated on the intermediate layer in this order, A copper foil with a carrier is described in which a layer is a chromium layer or chromate layer laminated on the copper foil carrier and a Ni layer or a Ni-phosphorus alloy layer.

  However, since the copper foil with a carrier described in Patent Document 3 is a peeled form in which the Ni layer or the Ni-phosphorus alloy layer cohesively breaks, the ultrathin copper foil layer may be broken depending on circumstances.

  In addition, all of the composite foils with carriers described in Patent Documents 1 to 3 have an ultrathin copper foil formed on a Ni or Ni alloy layer, and roughen the surface of the ultrathin copper foil to form a substrate. Since it is described that bonding is performed, even if the Ni or Ni alloy layer can be selectively removed after bonding to the base material, the ultrathin copper foil and the roughened particles will remain. There is a problem in that the thickness of the entire substrate is increased.

The present inventors made it a technical subject to solve the above-mentioned problems, and as a result of many trial and error trials and experiments, the first results were obtained on at least one surface of the metal foil carrier and the metal foil carrier. And a composite metal foil in which a release layer, a second Ni layer and an ultrathin copper layer are laminated in this order on at least one surface of the first Ni or Ni alloy layer. there are, the pole primary particle size of the copper particles in the thin copper layer is 10 to 200 nm, the adhesion amount is 300~6000mg / m ^2, a thickness of the second Ni layer is a composite metal foil is 0.3~5μm If there is, even if it is bonded to the substrate at a high temperature, the release layer has extremely high heat resistance, so the metal foil carrier, the first Ni or Ni alloy layer, and the release layer are peeled cleanly at the interface of the release layer, making it extremely thin. A metal foil laminate in which a copper layer and a second Ni layer are laminated can be manufactured, and the second Ni layer can be obtained by selective etching. Since it can be easily removed, it is possible to manufacture a copper-clad laminate including an extremely thin copper layer that is dense and hardly generates pinholes, etc. It has achieved technical challenges.

  The technical problem can be solved by the present invention as follows.

The present invention is a metal foil carrier and a first Ni or Ni alloy layer is laminated on at least one surface of the metal foil carrier, a release layer on at least one surface of the first Ni or Ni alloy layer, A composite metal foil in which a second Ni layer and an ultrathin copper layer are laminated in this order, wherein the primary particle diameter of the copper particles of the ultrathin copper layer is 10 to 200 nm, and the adhesion amount is 300 to 6000 mg / m ² And the thickness of the second Ni layer is 0.3-5 μm.

  The present invention is the composite metal foil in which the first Ni or Ni alloy layer has a thickness of 0.001 to 5 μm.

  The present invention is the composite metal foil, wherein the release layer is a layer containing at least one of Cr and Zn.

  The present invention is the composite metal foil in which the Ni purity of the second Ni layer is 99.6% or more.

  The present invention is a composite metal foil in which a metal layer is formed between the second Ni layer and the ultrathin copper layer.

  In the present invention, after the insulating resin base material is heat-compressed and bonded to the ultrathin copper layer of the composite metal foil, the release layer, the first Ni or Ni alloy layer, and the metal foil carrier are bonded by the release layer. It is a manufacturing method of the metal-clad laminate manufactured by peeling.

  The present invention is also a method for producing a copper-clad laminate, wherein the metal-clad laminate is produced by removing the second Ni layer by etching with a Ni selective etching solution.

  According to the present invention, the peeling layer is sandwiched between the first Ni or Ni alloy layer and the second Ni layer, and the heat resistance of the peeling layer is extremely high. Even under severe temperature conditions, the metal foil carrier, the first Ni or Ni alloy layer, and the release layer can be easily separated at the interface of the release layer without lowering the release function.

  Further, according to the present invention, since the thickness of the second Ni layer is 0.3 to 5 μm, it is difficult for pinholes or the like to occur in the second Ni layer, and generation of pinholes in the ultrathin copper layer can be suppressed. .

  Further, since the second Ni layer can be removed by a Ni selective etching solution, a copper clad laminate on which an ultrathin copper layer is laminated can be manufactured by a simple method.

In addition, the ultrathin copper layer according to the present invention has a very fine ultrathin copper layer because the primary particle diameter of the copper particles to be formed is as small as 10 to 200 nm and the adhesion amount is 300 to 6000 mg / m ^2. become.

The primary particle size in the present invention is the particle size of the smallest unit (primary particle) (31) recognized as a particle among the precipitated copper particles, and the aggregate (32) of primary particles is defined as secondary particles. say.
In the present specification, the “dense ultrathin copper layer” refers to a copper layer as shown in FIG.

  When the circuit is formed using the ultra-thin copper layer according to the present invention as a seed layer for the additive method, the seed layer is very thin and can be removed by etching in a very short time. In addition, a fine pattern circuit can be formed.

  Moreover, since the ultra-thin copper layer which concerns on this invention is comprised with a precise | minute and fine copper particle, it is excellent in the adhesiveness at the time of bonding with a base material.

  Therefore, if the copper clad laminate produced by laminating with the composite metal foil according to the present invention is multilayered, the step of electroless plating and / or electrolytic plating of through holes and non-through holes, which are essential steps for interlayer connection However, even if the ultrathin copper layer is also thickened by plating, since the original thickness is extremely thin, an increase in the thickness of the entire multilayer substrate can be suppressed, and high density can be realized.

  In addition, the ultrathin copper layer according to the present invention is subjected to the same surface treatment as conventional copper foil for printed wiring boards, such as heat resistance / chemical resistance treatment, rust prevention treatment, chemical conversion treatment, etc. Can also be improved.

  Further, if the thickness of the first Ni or Ni alloy layer is 0.001 to 5 μm, the heat resistance of the release layer can be further improved.

  Moreover, if at least one of Cr or Zn is contained in the release layer, a composite metal foil having a further excellent release function can be obtained.

  The copper clad laminate according to the present invention can suitably form a fine pattern circuit by an additive method, and can also form a circuit by a subtractive method or other methods.

It is a schematic diagram of composite metal foil. It is a schematic diagram of one mode of composite metal foil. It is a schematic diagram of one mode of composite metal foil. It is a schematic diagram of the composite metal foil bonded together with the base material. It is a schematic diagram of a metal-clad laminate. It is a schematic diagram of a copper clad laminated board. It is a schematic diagram of the printed wiring board in which the circuit was formed. It is the schematic diagram which laminated | stacked the 2nd base material and the 2nd ultra-thin copper layer. It is the schematic diagram which formed the non-through-hole. It is a schematic diagram showing that the inner wall of the non-through hole was subjected to electroless plating and electrolytic plating. It is a schematic diagram of a multilayer printed wiring board. It is a FE-SEM photograph (300,000 times) of the ultra-thin copper layer in this invention.

  The metal foil carrier (2) in the present invention is not particularly limited, but a copper foil or a copper alloy foil formed by a rolling method or an electrolytic method can be suitably used.

  The surface on which each layer is laminated on the metal foil carrier (hereinafter referred to as “lamination surface”) may be appropriately selected as necessary, and may be both surfaces as shown in FIG.

  Although the thickness of a metal foil carrier is not specifically limited, 9-300 micrometers is preferable, More preferably, it is 12-70 micrometers.

  This is because if the thickness is less than 9 μm, wrinkles and cracks are likely to occur during lamination, and if it exceeds 300 μm, the rigidity of the composite metal foil becomes too strong and handling becomes difficult.

  Also, the same surface treatment as conventional copper foils for printed wiring boards, such as roughening treatment, heat and chemical resistance treatment, rust prevention treatment, and chemical conversion treatment, should be applied to the surface where each layer is not laminated on the metal foil carrier. Can do.

  When the surface of the second Ni layer (5) and the ultrathin copper layer (6) is made to have a low roughness, the surface roughness of the laminated surface Rzjis (ten-point average roughness described in JIS-B0601 (2013)) ) Is 1.0 μm or less of rolled copper foil or electrolytic copper foil may be used as the metal foil carrier.

  The thickness of the first Ni or Ni alloy layer (3) in the present invention is preferably 0.001 to 5 μm, more preferably 0.005 to 3 μm.

  If the thickness is less than 0.001 μm, it is likely to be affected by the high temperature when pasting to the substrate and it may be difficult to peel from the interface of the release layer, and even if it is thicker than 5 μm, it has further functions. It is because improvement cannot be expected.

  In order to function as a heat-resistant layer that prevents burning (oxidation) of the metal foil carrier in the heat-compression process that is laminated to the base material, as shown in FIG. 3, the first Ni or Only the Ni alloy layer (3) may be provided.

  The composite metal foil in the present invention comprises a metal foil carrier (2), a first Ni or Ni alloy layer (3), a release layer (4), and an interface between the release layer (4) and the second Ni layer (5). Can be peeled off.

  The release layer (4) preferably contains at least one of Cr and Zn.

  As a layer containing Cr or Zn, a single metal layer composed of one element of Cr or Zn, a hydrate layer, an oxide layer, an alloy layer composed of two elements, a hydrate layer, an oxidation Examples include a physical layer, a single metal, a hydrate, an oxide, an alloy of the two kinds of elements, a hydrate, a composite oxide layer, or the like.

The adhesion amount of the release layer is preferably 0.001 to 1000 mg / m ² , more preferably 0.05 to 1000 mg / m ² .

If it is less than 0.001 mg / m ² , peeling may be difficult, and even if it exceeds 1000 mg / m ² , further improvement in function cannot be expected.

  The desired peel strength can be adjusted by changing the thickness of the first Ni or Ni alloy layer (3), the type of metal of the release layer (4), and the amount of adhesion.

  The peel strength is preferably 0.1 kN / m or less, more preferably 0.05 kN / m or less after heating at 210 ° C. for 4 hours.

If it exceeds 0.1 kN / m, unintentional peeling can be prevented, but workability is lowered because a large force and time are required for peeling.
Moreover, it is because there exists a possibility that a board | substrate may warp and distortion by the force applied when peeling.

  The second Ni layer (5) preferably has a Ni purity of 99.6% or more. This is because if the purity is low, the removability by selective etching may be inferior or may not be removed.

  If the second Ni layer cannot be removed cleanly, the risk of insulation failure (circuit short) due to residual Ni during circuit formation increases.

The thickness of the second Ni layer is 0.3 to 5 μm, more preferably 1 to 3 μm.
If it is less than 0.3 μm, pinholes are likely to occur in the second Ni layer, and if there are pinholes in the second Ni layer, an ultrathin copper layer will not be formed at the pinhole locations, which may result in circuit disconnection risk. It is to increase.

  Further, even if the thickness exceeds 5 μm, further improvement in the function cannot be expected, and the removal process by selective etching takes time, which is not preferable.

The copper particles forming the ultrathin copper layer preferably have a primary particle diameter of 10 to 200 nm, more preferably 10 to 40 nm. Adhesion amount is 300~6000mg / m ^2, more preferably from 1000~4000mg / m ^2.

If the primary particle diameter is less than 10 nm, the surface energy increases remarkably, so that the shape of the particles cannot be maintained. If the particle diameter exceeds 200 nm, the particles are too large and are dense in an adhesion amount of 300 to 6000 mg / m ^2. This is because an ultrathin copper layer cannot be formed.

Also, if the adhesion amount is less than 300 mg / m ² , a dense ultrathin copper layer cannot be formed. If the adhesion amount exceeds 6000 mg / m ² , it takes time to remove or copper particles. Since the conductive foreign matter is generated by dropping off, it is not preferable.

  In addition, since the thickness of the ultra-thin copper layer concerning this invention is very thin and it is not easy to measure directly, it decided to represent with the adhesion amount.

  The ultra-thin copper layer is dense and composed of fine copper particles, so it has good adhesion to the base material. However, in order to further improve the adhesion, the known heat resistance / resistance to surface treatment of copper foil for printed wiring boards Chemical treatment, rust prevention treatment, chemical conversion treatment, etc. can also be performed.

  In addition, since the surface resistance of the second Ni layer is large, when the voltage during plating of the ultrathin copper layer becomes high or it becomes difficult to obtain adhesion, physical film formation such as sputtering or vapor deposition is performed. A metal layer may be provided on the second Ni layer and a very thin copper layer may be provided on the metal layer by a process or a chemical film formation process such as electrolytic plating or electroless plating.

  The composite metal foil, the copper clad laminate and the printed wiring board according to the present invention can be produced by the following method.

(First Ni or Ni alloy layer)
Watt bath (nickel sulfate 240-300 g / L, nickel chloride 40-70 g / L, boric acid 30-45 mL / L, pH 3.8-4.2, bath temperature 50-60 ° C., current density 0.5-8 A / dm ² ) And metal foil in sulfamic acid bath (nickel sulfamate 440-500 g / L, boric acid 30-50 mL / L, pH 3.8-4.4, bath temperature 50-60 ° C, current density 2-40 A / dm ² ) Electroplating by immersing the surface of the carrier, or hydrazine bath (typically nickel acetate 60 g / L, glycolic acid 60 g / L, ethylenediaminetetraacetic acid 25 g / L, hydrazine 100 mL / L, pH 11, bath temperature 90 ° C) etc. the surface of the metal foil carrier by electroless plating is immersed in, it is possible to form a Ni layer on the metal foil carrier.

  If necessary, additives such as brightener, sodium naphthalene sulfonate, sodium dodecyl sulfate, and saccharin can be added to the Watt bath and sulfamic acid bath as appropriate.

Ni-P (nickel sulfate 20-300 g / L, nickel chloride 35-50 g / L, boric acid 30-50 g / L, phosphorous acid 1-30 g / L, sodium acetate 1-30 g / L, pH 1-5, bath temperature 40-70 ° C, current density 1-15A / dm ² ), Ni-Co (nickel sulfate 50-200g / L, cobalt sulfate 50-200g / L, sodium citrate 15-30g / L, pH 3-6, bath temperature 25-60 ° C, current density 1-15 A / dm ² ), Ni-Mo (nickel sulfate 30-70 g / L, sodium molybdate 30-120 g / L, sodium citrate 15- 30g / L, pH 7-12, bath temperature 20-50 ° C, current density 1-15A / dm ² ), Ni-Zn (nickel sulfate 250-300g / L, zinc sulfate 50-400g / L, sodium citrate 15- 30g / L, pH 3-6, bath temperature 50-70 ° C, current density 3-15A / dm ² ), Ni-Co-Mo (nickel sulfate 50-200g / L, cobalt sulfate 50-200g / L, sodium molybdate) 30 to 120 g / L, sodium citrate 15~30g / L, pH7~12, bath temperature 20 to 50 ° C., a current density of 1 through 15A / dm ²⁾ bath, etc. Electroplating by dipping the surface of the metal foil carrier, or Ni-P (typically nickel chloride 16g / L, sodium phosphinate 24g / L, sodium succinate 16g / L, sodium malate 18g / L, pH 5. 6, bath temperature 100 ° C), Ni-B (typically, nickel chloride 30g / L, ethylenediamine 60g / L, sodium hydroxide 40g / L, sodium tetrahydroborate 0.6g / L, bath temperature 90 ° C) The Ni alloy layer can be formed on the metal foil carrier by immersing the surface of the metal foil carrier and performing electroless plating.

  Ni-P, Ni-Co, Ni-Mo, Ni-Zn, Ni-Co-Mo baths may contain appropriate amounts of additives such as brightener, saccharin, sodium naphthalene sulfonate, sodium dodecyl sulfate, etc. You can also

(Peeling layer)
Chromic anhydride 200-400 g / L, sulfuric acid 1.5-4 g / L, pH 1-4, bath temperature 45-60 ° C., current density 10-40 A / dm ² , or chromic anhydride or potassium dichromate 1-30 g / L , PH 2-6, bath temperature 20-60 ° C, current density 0.1-10 A / dm ² , or potassium dichromate 1-30 g / L, zinc sulfate 0.1-20 g / L, pH 2-6, bath temperature 20-60 ° C The surface on which the first Ni or Ni alloy layer is formed is immersed in a plating bath having a current density of 0.1 to 10 A / dm ² and can be formed by electroplating.

(Second Ni layer)
The surface on which the release layer is formed can be immersed in a watt bath or a sulfamic acid bath to form a second Ni layer by electroplating.

  If formed by the electrolytic method, the Ni purity can be increased to 99.6% or higher.

(Ultra-thin copper layer)
The ultrathin copper layer can be formed, for example, by the method described in JP-A-1-246393.
Specifically, diethylenetriaminepentaacetic acid pentasodium 10 to 300 g / L, copper sulfate pentahydrate 10 to 100 g / L was adjusted to pH 2.5 to 13.0 with sulfuric acid, bath temperature 30 to 60 ° C, current density 2 to It can be formed by treating at 10 A / dm ² for 1 to 120 seconds.

(Base material)
The composite metal foil according to the present invention is less likely to have a peeling function at high temperatures, and even a resin having a high glass transition temperature can be easily peeled after being laminated by heat compression. It is not limited and can be selected appropriately.

(Metal-clad laminate)
After bonding the ultra-thin copper layer of the composite metal foil and the base material by heat compression, the release layer, the first Ni or Ni alloy layer, and the metal foil carrier are peeled off from the release layer interface to produce a metal-clad laminate. (Figure 5).

(Copper clad laminate)
By removing the second Ni layer from the metal-clad laminate by Ni selective etching, a copper-clad laminate in which an ultrathin copper layer is laminated on the substrate can be produced (FIG. 6).

  In the present invention, a double-sided metal-clad laminate or a double-sided copper-clad laminate can be produced by laminating composite metal foils on both sides of a substrate.

(Printed wiring board)
If an ultra-thin copper layer on a copper clad laminate is used as a seed layer, a fine pattern circuit can be formed by an additive method (FIG. 7).

  In addition, a circuit can also be formed in the ultra-thin copper layer on a copper clad laminated board by a subtractive construction method or other construction methods.

(Multilayer printed wiring board)
Further, the formed circuit is roughened, and the second base material (7 (a)) and the composite metal foil according to the present invention are laminated on the roughened circuit by heat compression, and the composite metal foil according to the present invention is used. A second ultrathin copper layer (6 (a)) is formed (FIG. 8), and the second ultrathin copper layer and the second substrate are non-through holes (12) until the roughened circuit is reached. (FIG. 9), the inner walls of the non-through holes are connected by electroless plating (13) and electrolytic plating (20) (FIG. 10), and the circuit (10 (a )) Can also be formed.

  A circuit (10 (b)) can be further formed on the second circuit (10 (a)) by the same method (FIG. 11).

  If the copper-clad laminate according to the present invention is laminated to form a multilayer, it is possible to suppress the thickness of the entire multilayer substrate and realize a high density of the multilayer substrate.

  The multilayer printed wiring board is not limited to the composite metal foil according to the present invention, and a conventional copper foil for printed wiring board may be laminated.

  Examples and Comparative Examples of the present invention are shown below, but the present invention is not limited thereto.

(Example 1)
As the metal foil carrier, an electrolytic copper foil having a thickness of 18 μm was used.

The surface of the copper foil carrier is immersed in a watt bath (bath composition: nickel sulfate 250 g / L, nickel chloride 50 g / L, boric acid 30 mL / L, pH 4.0, bath temperature 50 ° C.), 30 at a current density of 5 A / dm ² The first Ni layer was formed by treating for 2 seconds.

The surface on which the first Ni layer was formed was immersed in a plating bath with potassium dichromate 20 g / L, pH 4.5, bath temperature 30 ° C., and treated at a current density of 1 A / dm ² for 2 seconds to obtain Cr water. A Japanese composite was formed into a release layer.

The surface on which the release layer was formed was immersed in the same watt bath as the first Ni layer, and treated at a current density of 5 A / dm ² for 120 seconds to form a second Ni layer.

The surface on which the second Ni layer was formed was immersed in a plating bath of diethylenetriaminepentaacetic acid pentasodium 20 g / L, copper sulfate pentahydrate 30 g / L, pH 4.0, bath temperature 40 ° C., and a current density of 2 A / dm ² For 30 seconds to form an ultrathin copper layer.

  The primary particle diameter of the copper particles forming the ultrathin copper layer was 10 to 40 nm.

(Example 2)
From a composite consisting of Cr and Zn by dipping in a plating bath with potassium dichromate 15g / L, zinc sulfate 10g / L, pH 4.9, bath temperature 30 ° C and treating with current density 0.5A / dm ² for 2 seconds It was produced in the same manner as in Example 1 except that a release layer was formed.
(Example 3)
Nickel sulfate 30g / L, phosphorous acid 2g / L, sodium acetate 10g / L, pH 4.5, bath temperature 30 ° C, immersed in a plating bath, treated with current density 2A / dm ² for 5 seconds from Ni and P This was manufactured in the same manner as in Example 1 except that an alloy layer was formed.
(Example 4)
Nickel sulfate 50g / L, cobalt sulfate 50g / L, citric acid 30g / L, pH 4.0, bath temperature 30 ° C, immersed in a plating bath, treated with current density 2A / dm ² for 2 seconds and made of Ni and Co Manufactured in the same manner as in Example 1 except that an alloy layer was formed.
(Example 5)
Nickel sulfate 50g / L , sodium molybdate 30g / L, citric acid 30g / L, pH 9.0, bath temperature 30 ° C, immersed in a plating bath, treated with current density 7A / dm ² for 2 seconds from Ni, Mo This was manufactured in the same manner as in Example 1 except that an alloy layer was formed.
(Example 6)
Nickel sulfate 250g / L, zinc sulfate 50g / L, citric acid 30g / L, pH 4.0, bath temperature 50 ° C, immersed in a plating bath, treated with current density 5A / dm ² for 2 seconds, consisting of Ni and Zn Manufactured in the same manner as in Example 1 except that an alloy layer was formed.
(Example 7)
Immerse in a plating bath with nickel sulfate 50 g / L, cobalt sulfate 50 g / L, sodium molybdate 30 g / L, citric acid 30 g / L, pH 9.0, bath temperature 30 ° C, and treat for 2 seconds at a current density of 7 A / dm ² Then, it was manufactured in the same manner as in Example 1 except that an alloy layer made of Ni, Co, and Mo was formed.
(Examples 8 to 15)
It was produced in the same manner as in Example 1 except that the thickness of the first Ni layer, the adhesion amount of the release layer, or the adhesion amount of the ultrathin copper layer was changed as shown in Table 1.
(Example 16)
It was manufactured in the same manner as in Example 1 except that a copper layer was provided by Cu sputtering between the second Ni layer and the ultrathin copper layer.

(Example 17)
It was manufactured in the same manner as in Example 1 except that a copper layer was provided by Cu vapor deposition between the second Ni layer and the ultrathin copper layer.

(Comparative Example 1)
It was produced in the same manner as in Example 1 except that no release layer was formed.
(Comparative Example 2)
It was produced in the same manner as in Example 1 except that the first Ni layer was not formed.
(Comparative Examples 3-8)
It was produced in the same manner as in Example 1 except that the thickness of the first Ni layer, the adhesion amount of the release layer, or the adhesion amount of the ultrathin copper layer was changed as shown in Table 1.

(Peel strength)
The composite metal foils of Examples and Comparative Examples were heated in an atmospheric oven heated to 210 ° C. for 2 hours and 4 hours.

Then, it fixed to the flat support plate and measured peeling strength in accordance with the peeling strength test method in JIS-C6481 (1996) in PT50N by Minebea Co., Ltd.
Further, as to whether or not peeling was possible, those that could be peeled were evaluated as ◯ and those that could not be peeled were evaluated as ×.

  The metal-clad laminate from which the copper foil carrier had been peeled was rocked and immersed in a Ni selective etching solution (Mekkuri Mover NH-1866 Mec Co., Ltd.), and the time (seconds) required to remove the second Ni layer was measured.

  In addition, the ultra-fine pattern circuit of L / S = 10μm / 10μm is formed by the additive method on the copper clad laminate from which the second Ni layer has been removed, using the ultra-thin copper layer as a seed layer. As for, the case where L / S = 10 μm / 10 μm was formed was evaluated as ○, and the case where it was not formed was evaluated as ×.

Table 1 shows the composite metal foils of Examples and Comparative Examples.
Table 2 shows the evaluation of each example and comparative example.

From the examples and comparative examples, the composite metal foil according to the present invention has low peel strength even after heating at 210 ° C. for 4 hours, and can be easily peeled, and L / S = 10 μm / 10 μm It has been proved that even an ultrafine pattern circuit can be suitably formed.
Further, in Comparative Example 4 and Comparative Example 6, the thickness of the Ni layer is large, which increases the cost, which is not preferable. Furthermore, in Comparative Example 6, it takes time to remove the second Ni layer, which is not preferable.

The composite metal foil according to the present invention is less likely to deteriorate the release function of the release layer even at high temperatures. Therefore, even when laminated to a substrate having a high glass transition temperature at high temperatures, the composite metal foil has low and stable peel strength. The carrier, the first Ni or Ni alloy layer, and the release layer can be easily peeled from the interface of the release layer.
In addition, since the second Ni layer can be removed by selective etching, a copper-clad laminate in which dense ultrathin copper layers are laminated can be produced by a simple method.
In addition, since the copper clad laminate manufactured using the composite metal foil according to the present invention has a very thin copper layer, when the circuit is formed by an additive method using the ultrathin copper layer as a seed layer, an etching treatment is performed. Since the seed layer can be removed in a short time and etching to the circuit can be suppressed, even a circuit with an ultrafine pattern such as L / S = 10 μm / 10 μm can be formed suitably, and pinholes are also generated. Since it is difficult, printed wiring boards with low risk of circuit disconnection can be manufactured, and in multilayering, when connecting through holes and non-through holes with electroless plating and / or electrolytic plating, the ultrathin copper layer is also Since the influence of plating and becoming thick can be suppressed to a minimum, an increase in the overall thickness of the multilayer substrate can be suppressed, and a high-density multilayer substrate can be manufactured.
Therefore, it can be said that the present invention has high industrial applicability.

DESCRIPTION OF SYMBOLS 1 Composite metal foil 2 Metal foil carrier 3 1st Ni or Ni alloy layer 4 Release layer 5 2nd Ni layer 6 Ultrathin copper layer 6 (a) 2nd ultrathin copper layer 7 Base material 7 (a) First 2 substrate 8 metal clad laminate 9 copper clad laminate 10 circuit 10 (a) second layer circuit 10 (b) third layer circuit 12 non-through hole 13 electroless plating 16 multilayer printed wiring board 20 electroplating 31 Primary particle 32 Secondary particle

Claims (7)

A first Ni or Ni alloy layer is laminated on at least one surface of the metal foil carrier and the metal foil carrier, and a release layer and a second Ni are formed on at least one surface of the first Ni or Ni alloy layer. layers and ultra thin copper layer is a composite metal foil which are laminated in this order, a primary particle size of the copper particles of the ultra-thin copper layer is 10 to 200 nm, the adhesion amount is 300~6000mg / m ^2, wherein A composite metal foil in which the thickness of the second Ni layer is 0.3 to 5 μm. 2. The composite metal foil according to claim 1, wherein the thickness of the first Ni or Ni alloy layer is 0.001 to 5 μm. 3. The composite metal foil according to claim 1, wherein the release layer is a layer containing at least one of Cr and Zn. 4. The composite metal foil according to claim 1, wherein the purity of Ni in the second Ni layer is 99.6% or more. 5. The composite metal foil according to claim 1, wherein a metal layer is formed between the second Ni layer and the ultrathin copper layer. An insulating resin base material is heat-compressed and bonded to the ultrathin copper layer of the composite metal foil according to any one of claims 1 to 5, and then the release layer and the first Ni or Ni alloy layer and the metal foil are formed by the release layer. A method for producing a metal-clad laminate produced by peeling off a carrier. 7. A method for producing a copper-clad laminate, wherein the metal-clad laminate produced by the method according to claim 6 is produced by etching away the second Ni layer with a Ni selective etching solution.