KR102118245B1 - Composite metal foil, copper-clad laminate using the composite metal foil, and manufacturing method of the copper-clad laminate - Google Patents

Abstract

(Task) A copper-clad laminate in which a very thin, dense, and ultra-thin copper layer in which pinholes are unlikely to be laminated can be manufactured by a simple method, and a circuit is formed by an additive method using the ultra-thin copper layer as a seed layer. If it is, the seed layer can be etched and removed in a short time, so that etching to the circuit can be suppressed, and when a multi-layered substrate is manufactured using the copper-clad laminate, the entire multi-layered substrate is suppressed from being thickened, and a high-density multi-layer A composite metal foil that can be used as a substrate is provided.
(Solution) 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, a second Ni layer, and an ultrathin layer are formed on at least one surface of the first Ni or Ni alloy layer. A composite metal foil in which a copper layer is laminated in this order, the primary particle diameter of the copper particles of the ultra-thin copper foil layer is 10 to 200 nm, the adhesion amount is 300 to 6000 mg/m 2, and the thickness of the second Ni layer is 0.3 to 5 Composite metal foil of µm.

Description

Composite metal foil and a copper-clad laminate using the composite metal foil and a method of manufacturing the copper-clad laminate

The present invention relates to a composite metal foil, a copper-clad laminate using the composite metal foil, and a method for manufacturing the copper-clad laminate.

Specifically, the composite metal foil can be produced by a simple method of manufacturing a copper-clad laminate in which an ultra-thin copper layer is laminated. Moreover, since the ultra-thin copper layer is very thin and dense and hard to generate pinholes, the ultra-thin copper If the layer is a seed layer of an additive construction method, since the seed layer can be etched and removed in a short time, etching of the circuit itself can be suppressed to form a circuit of a fine pattern, and a copper-clad laminate made of the composite metal foil can be formed. When a multi-layered substrate is manufactured by using, the copper layer itself is very thin even when electroless plating and/or electrolytic plating of through-holes or non-through holes for interlayer connection is suppressed, thereby suppressing the overall thickness of the multi-layered substrate and suppressing the high-density multilayered substrate. It relates to a composite metal foil that can be produced, a copper-clad laminate using the composite metal foil, and a method for manufacturing the copper-clad laminate.

In an electronic device requiring miniaturization and an increase in processing speed, a printed circuit board in which a circuit with a fine pattern (hereinafter referred to as a "fine pattern") is formed, or a package substrate in which semiconductor elements are mounted at a high density by using a printed wiring board having a multilayer structure It is equipped with.

In addition, a build-up substrate is used for redistribution in the mounted device, and a fine pattern circuit is desired in this build-up substrate as the device is miniaturized.

The width of the line and the line (=space) (hereinafter referred to as "L/S"), which is conventionally called a circuit of fine patterns, was L/S = 30 µm /30 µm, but recently L/S = 15 µm /15 There is also a demand for a circuit with an ultrafine pattern of µm, furthermore, L/S=10 µm/10 µm.

In general, as a copper-clad laminate for forming a circuit of a fine pattern, a copper-clad laminate with an ultra-thin copper foil attached to an insulating resin substrate (hereinafter referred to as "substrate") is used. There is a problem that wrinkles and cracks are likely to occur when pasted on a coated laminate.

Therefore, the ultra-thin copper foil is obtained by subjecting the surface of the ultra-thin copper foil of the composite metal foil on which the ultra-thin copper foil is laminated on a support (hereinafter referred to as “carrier”) to a surface of the ultra-thin copper foil and then attaching it to the substrate and then peeling the carrier. A method of manufacturing a laminated copper-clad laminate has been developed.

As a method of manufacturing a copper-clad laminate in which an ultra-thin copper foil layer is laminated, in addition to using an ultra-thin copper foil with a carrier, a copper foil of 12 µm or less is attached, and the copper foil is thinned by half etching technique or the like to form an ultra-thin copper foil layer. How to do is also being developed.

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

However, in the subtractive construction method, if the thickness of the conductor (the ultrathin copper foil layer) is the same, it cannot be used as a circuit.

If plating is performed to thicken, there is a problem that the space portion is narrowed by plating grown from the line portion, and as a result, formation of a circuit of a fine pattern is difficult.

In the additive method, the thickness of the conductor can be controlled by electrolytic plating, but since the layer composed of the roughening treatment of the ultrathin copper foil and the ultrathin copper foil surface becomes the seed layer, the seed layer cannot be removed in a short time by etching. , Since even the circuit is etched during etching, there is a problem that it is difficult to form a fine pattern circuit.

If the ultra-thin copper foil layer is made thinner by half-etching technique or the like, the etching time may be shortened, so that the etching of the circuit can be suppressed, but the amount of etching of the ultra-thin copper foil layer must be controlled very precisely. The foil thickness distribution is also very difficult because very high precision is required.

Moreover, if the ultra-thin copper foil itself is made thin, the etching time is shortened, so that etching of the circuit can be suppressed, but pinholes are likely to occur, and the pinhole portion causes the circuit to be defective. In the circuit of the fine pattern, if the circuit is even slightly damaged, the risk of circuit breakage increases, which is a problem.

In addition, since both the subtractive method and the additive method, the ultra-thin copper foil layer is also thickened by the electroless plating and/or electrolytic plating process of through-holes or non-through holes, which are essential processes for interlayer connection during multilayering. As a result, there is a problem that the entire substrate becomes thick, and densification is hindered.

Therefore, it is a copper-clad laminate having an ultra-thin copper layer thinner than the ultra-thin copper foil layer. If the ultra-thin copper layer is used as a seed layer of an additive construction method, etching can be removed in a very short time, and etching of the circuit can be suppressed. Therefore, it can be preferably used for the formation of a fine pattern circuit, and also, when multi-layered, it is possible to suppress an increase in the overall thickness. Thus, a copper coating comprising an ultra-thin copper layer capable of producing a high-density multi-layer substrate Development of a composite metal foil capable of manufacturing a laminated plate in a simple manner is desired.

Japanese Patent Application Publication No. 2009-246120 WO 2002-024444 Japanese Patent Publication No. 2013-204065

Patent Literature 1 discloses a Fe-Ni alloy layer, a copper or copper alloy layer formed with a release layer on a carrier foil, and a composite foil with a carrier laminated in this order.

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

In addition, since the roughening treatment layer is formed on the copper or copper alloy layer when the substrate is pasted, the seed layer cannot be etched and removed in a short time if used as a seed layer of an additive construction method, and even the circuit is etched, resulting in a fine pattern circuit. There is a fear that can not be formed.

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

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

However, in the ultra-thin copper foil with a carrier described in Patent Document 2, as in the composite foil with a carrier described in Patent Document 1, since the release layer is laminated on the carrier foil, the heat resistance of the peeling function is low, and the carrier foil peels neatly at the interface. There is a problem that it does not work.

In addition, since the Ni layer on the ultra-thin copper foil layer is very thin, there is a high possibility that pinholes are generated in the Ni layer, and when the pinholes are generated in the Ni layer, there is a problem that a pinhole is generated in the electrolytic copper plating layer, resulting in defects in the circuit.

In Patent Document 3, a copper foil with a carrier in which a copper foil carrier, an intermediate layer laminated on a copper foil carrier, and an ultra-thin copper foil layer on the intermediate layer are laminated in this order, wherein the intermediate layer is laminated on the copper foil carrier or chromate A layer and a copper foil with a carrier which is a Ni layer or a Ni-phosphorus alloy layer are described.

However, in the copper foil with a carrier described in patent document 3, since it is a peeling form which is cohesively destroyed in a Ni layer or a Ni-phosphorus alloy layer, there is a possibility that the ultrathin copper foil layer may be destroyed in some cases.

In addition, since all of the composite foils with carriers described in Patent Documents 1 to 3 are formed of an ultrathin copper foil on a Ni or Ni alloy layer, it is described that the surface of the ultrathin copper foil is roughened and attached to the substrate. Even if the Ni or Ni alloy layer can be selectively removed, since the ultra-thin copper foil and the roughened particles remain, there is a problem that the thickness of the entire substrate increases during multilayering.

The present inventors, as a technical problem to solve the above problems, as a result of repeated trials and errors starting and experimenting, a first Ni or Ni alloy layer is laminated on at least one surface of the metal foil carrier and the metal foil carrier , A composite metal foil in which a release layer, a second Ni layer and an ultra-thin copper layer are laminated in this order on at least one of the first Ni or Ni alloy layers, wherein the primary particle diameter of the copper particles of the ultra-thin copper foil layer is 10 to If the composite metal foil having a thickness of 200 nm and an adhesion amount of 300 to 6000 mg/m 2 and the thickness of the second Ni layer is 0.3 to 5 μm, even if the substrate is attached at a high temperature, the heat resistance of the release layer is very high, so that the metal foil carrier and the The 1 Ni or Ni alloy layer and the release layer can be neatly peeled at the release layer interface to produce a metal foil laminate in which an ultra-thin copper layer and a second Ni layer are stacked, and the second Ni layer can be easily made by selective etching. Since it can be removed, the technical problem has been achieved by obtaining remarkable knowledge that a copper-clad laminate having an ultra-thin copper layer, which is dense and hard to generate pinholes, can be manufactured by a very simple method.

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

In the present invention, 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, a second Ni layer, and ultra-thin copper are disposed on at least one surface of the first Ni or Ni alloy layer. As a composite metal foil in which layers are laminated in this order, the primary particle diameter of the copper particles of the ultra-thin copper layer is 10 to 200 nm, the adhesion amount is 300 to 6000 mg/m 2, and the thickness of the second Ni layer is 0.3 to 5 μm. It is a phosphorus composite metal foil.

Further, the present invention is a composite metal foil having a thickness of the first Ni or Ni alloy layer of 0.001 to 5 μm.

Moreover, this invention is a composite metal foil in which the said peeling layer is a layer containing at least 1 sort(s) of Cr and Zn.

Further, the present invention is a composite metal foil in which the purity of Ni of the second Ni layer is 99.6% by mass or more.

Further, the present invention is a composite metal foil in which a metal layer is formed between the second Ni layer and the ultra-thin copper layer.

In addition, the present invention is a metal-clad laminate prepared by heating and compressing an insulating resin substrate to the ultra-thin copper layer of the composite metal foil, and then peeling the release layer and the first Ni or Ni alloy layer and the metal foil carrier with the release layer. It is a manufacturing method.

Moreover, this invention is the manufacturing method of the copper clad laminated board which manufactures the said metal-clad laminated board by etching removing the said 2nd Ni layer with Ni selective etching liquid.

In addition, the present invention is a printed wiring board characterized in that a circuit is formed using the copper-clad laminate.

Further, the present invention is a multilayer printed wiring board in which one or more circuits are further formed on the circuit of the printed wiring board.

According to the present invention, since the release layer is a structure sandwiched between the first Ni or Ni alloy layer and the second Ni layer, and the heat resistance of the release layer is very high, even under severe temperature conditions when attaching a substrate having a high glass transition temperature The peeling function is not lowered, and the metal foil carrier, the first Ni or Ni alloy layer, and the peeling layer can be easily peeled off at the peeling layer interface.

Further, according to the present invention, since the thickness of the second Ni layer is 0.3 to 5 µm, pinholes and the like are unlikely to occur in the second Ni layer, and it is possible to suppress the occurrence of pinholes in the ultrathin copper layer.

Moreover, since the 2nd Ni layer can be removed with Ni selective etching liquid, the copper-clad laminated board in which the ultra-thin copper layer was laminated|stacked can be manufactured by a simple method.

Moreover, the ultra-thin copper layer which concerns on this invention becomes a very dense ultra-thin copper layer because the primary particle diameter of the copper particle formed is small as 10-200 nm, and the adhesion amount is 300-6000 mg/m<2>.

In addition, the primary particle diameter in this invention is the particle diameter of the smallest unit (primary particle) 31 recognized as a particle among the precipitated copper particles, and the aggregate 32 of primary particles is called secondary particle. .

The "fine ultrathin copper layer" in this specification means the copper layer as shown in FIG.

When the circuit is formed using the ultrathin copper layer according to the present invention as a seed layer of an additive construction method, since the seed layer is very thin and can be etched away in a very short time, etching to the circuit is suppressed and fine patterns are formed. The circuit can be formed.

Moreover, since the ultra-thin copper layer which concerns on this invention consists of dense and fine copper particle, it is excellent in the adhesiveness at the time of sticking with a base material.

Therefore, when multilayered using the copper-clad laminate prepared by pasting with the composite metal foil according to the present invention, in the process of electroless plating and/or electrolytic plating of through-holes or non-through holes, which are essential steps for interlayer connection, the ultra-thin copper layer also Even if it is plated and thickened, since the original thickness is very thin, an increase in the thickness of the entire multilayer substrate can be suppressed, and high density can be realized.

In addition, the ultra-thin copper layer according to the present invention may be subjected to the same surface treatment as conventional copper foils for printed wiring boards such as heat resistance/chemical resistance treatment, rust prevention treatment, chemical conversion treatment, and further improve adhesion.

In addition, when 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, when at least one of Cr or Zn is contained in the peeling layer, it becomes a composite metal foil excellent in peeling function.

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

1 is a schematic view of a composite metal foil.
2 is a schematic view of an aspect of a composite metal foil.
3 is a schematic view of an aspect of a composite metal foil.
4 is a schematic view of a composite metal foil pasted with a base material.
5 is a schematic view of a metal-clad laminate.
6 is a schematic view of a copper-clad laminate.
It is a schematic diagram of the printed wiring board in which the circuit was formed.
It is a schematic diagram which laminated|stacked the 2nd base material and 2nd ultra-thin copper layer.
9 is a schematic view of forming a non-penetrating hole.
10 is a schematic view showing electroless plating and electrolytic plating on an inner wall of a non-penetrating hole.
It is a schematic diagram of a multilayer printed wiring board.
Fig. 12 is an FE-SEM photograph (300,000 times) of the ultra-thin copper layer in the present invention.

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

The surface for laminating each layer on the metal foil carrier (hereinafter referred to as "laminated surface") may be appropriately selected as necessary, and may be double-sided as shown in FIG. 2.

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 stiffness of the entire composite metal foil becomes too strong, making handling difficult.

Moreover, the surface treatment which does not laminate each layer on a metal foil carrier can be given the same surface treatment as conventional copper foil for printed wiring boards, such as a roughening treatment, heat resistance, chemical resistance treatment, rust prevention treatment, chemical conversion treatment, and the like.

In addition, when the surfaces of the second Ni layer 5 and the ultra-thin copper layer 6 are made to have low roughness, the surface roughness Rzjis of the laminated surface (10 points average roughness described in JIS-B0601 (2013)) is 1.0 µm or less. You may use copper foil or electrolytic copper foil as a 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 high temperature when applied to the substrate, and it may be difficult to peel from the peeling layer interface.

In the heat-compression process to be attached to the substrate, in order to function as a heat-resistant layer that prevents burning (oxidation) of the metal foil carrier, as shown in FIG. 3, a first Ni or Ni alloy is formed on the surface opposite to the surface on which each layer is laminated. You may form only the layer (3).

In the composite metal foil in the present invention, the metal foil carrier 2 and the first Ni or Ni alloy layer 3 and the release layer 4 are separated at the interface between the release layer 4 and the second Ni layer 5. Can be.

It is preferable that the release layer 4 contains at least one of Cr or Zn.

As a layer containing Cr or Zn, a single metal layer, a hydrate layer, an oxide layer made of any one element of Cr, Zn, or an alloy layer, a hydrate layer, an oxide layer made of two kinds of elements, or a single metal thereof , Hydrates, oxides, alloys of the two kinds of elements, hydrates, oxide composite layers, and 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.

By changing the thickness of the 1st Ni or Ni alloy layer 3 or the kind and adhesion amount of the metal of the peeling layer 4, it can adjust to a preferable peeling strength.

The peeling 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 is larger than 0.1 kN/m, unintended peeling can be prevented, but because peeling requires a great force and time, the workability deteriorates.

Moreover, it is because there is a possibility that warpage or deformation may occur in the substrate by the force applied when peeling.

It is preferable that the purity of Ni of the 2nd Ni layer 5 is 99.6 mass% or more. This is because when the purity is low, there is a possibility that the removal property in the selective etching is poor or cannot be removed.

If the second Ni layer is not neatly removed, the risk of poor insulation (circuit short) by Ni remaining in the circuit formation increases.

The thickness of the second Ni layer is 0.3 to 5 μm, more preferably 1 to 3 μm.

This is because 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 is not formed at the pinhole point, and the risk of circuit breakage increases.

Further, even if the thickness exceeds 5 µm, an improvement in additional functions cannot be expected, and it is not preferable because the removal process by selective etching takes time.

The copper particles forming the ultra-thin copper layer preferably have a primary particle diameter of 10 to 200 nm, more preferably 10 to 40 nm. The adhesion amount is 300 to 6000 mg/m 2, more preferably 1000 to 4000 mg/m 2.

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

Moreover, if the adhesion amount is less than 300 mg/m 2, a dense ultra-thin copper layer cannot be formed, and if it exceeds 6000 mg/m 2, it takes time to remove, or a conductive foreign substance is generated due to dropping of copper particles. Neither is preferable because it does.

Moreover, since the thickness of the ultra-thin copper layer which concerns on this invention is very thin and it is not easy to measure directly, it was set as the adhesion amount.

Since the ultra-thin copper layer is composed of dense and fine copper particles, the adhesion to the substrate is good, but in order to further improve the adhesion, heat-resistance/chemical resistance treatment, anti-rust treatment, chemical conversion treatment, etc., which are known as surface treatment of the copper foil for printed wiring boards, etc. You can also do

In addition, because the surface resistance of the second Ni layer is large, when the voltage at the time of plating of the ultra-thin copper layer is high or the adhesion is difficult to obtain, a physical film forming process such as sputtering or vapor deposition, or electrolytic plating or electroless plating A metal layer may be formed on the second Ni layer by a chemical film forming process such as, and an ultrathin copper layer may be formed on the metal layer.

The composite metal foil, copper-clad laminate and 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/d㎡) The surface of the metal foil carrier in an ina sulfamic acid bath (nickel sulfamate 440 to 500 g/L, boric acid 30 to 50 ml/L, pH 3.8 to 4.4, bath temperature 50 to 60°C, current density 2 to 40 A/d㎡) Electrolytic plating by immersion, or hydrazine bath (as representative examples, 60 g/L of nickel acetate, 60 g/L of glycolic acid, 25 g/L of ethylenediamine tetraacetic acid, 100 ml/L of hydrazine, pH 11, 90°C bath temperature) The Ni layer can be formed on the metal foil carrier by immersing the surface of the metal carrier on the back and electroless plating.

If necessary, additives such as brighteners, sodium naphthalenesulfonate, sodium dodecylsulfate, and saccharin may be added to the watt bath and sulfamic acid bath.

To form a Ni alloy layer, Ni-P (20 to 300 g/L of nickel sulfate, 35 to 50 g/L of nickel chloride, 30 to 50 g/L of boric acid, 1 to 30 g/L of phosphorous acid, 1 to 30 of sodium acetate g/ℓ, pH 1 to 5, bath temperature 40 to 70°C, current density 1 to 15 A/d㎡, Ni-Co (50 to 200 g/L nickel sulfate, 50 to 200 g/L cobalt sulfate, sodium citrate) 15 to 30 g/L, pH 3 to 6, bath temperature 25 to 60°C, current density 1 to 15 A/d㎡, Ni-Mo (30 to 70 g/L nickel sulfate, 30 to 120 g/sodium molybdate) ℓ, sodium citrate 15-30 g/ℓ, pH 7-12, bath temperature 20-50°C, current density 1-15 A/d㎡), Ni-Zn (nickel sulfate 250-300 g/ℓ, zinc sulfate 50- 400 g/L, sodium citrate 15-30 g/L, pH 3-6, bath temperature 50-70°C, current density 3-15 A/d㎡), Ni-Co-Mo (nickel sulfate 50-200 g/L , Cobalt sulfate 50-200 g/L, sodium molybdate 30-120 g/L, sodium citrate 15-30 g/L, pH 7-12, bath temperature 20-50°C, current density 1-15 A/d㎡) Electrolytic plating by immersing the surface of the metal foil carrier in a bath or the like, or Ni-P (16 g/L nickel chloride, 24 g/L sodium phosphinate, 16 g/L sodium succinate, 18 g/L sodium malate, pH 5.6, bath temperature 100° C.), Ni-B (as representative examples, nickel chloride 30 g/L, ethylenediamine 60 g/L, sodium hydroxide 40 g/L, sodium tetrahydroborate 0.6 g/L, bath temperature 90° C.), etc. The Ni alloy layer can be formed on the metal foil carrier by immersing the surface of the metal foil carrier and electroless plating.

To the Ni-P, Ni-Co, Ni-Mo, Ni-Zn, and Ni-Co-Mo baths, an appropriate amount of additives such as brighteners, saccharin, sodium naphthalenesulfonate, and sodium dodecylsulfate may be added as necessary.

(Peeling layer)

Chromic anhydride 200 to 400 g/L, sulfuric acid 1.5 to 4 g/L, pH 1 to 4, bath temperature 45 to 60°C, current density 10 to 40 A/d㎡, or chromic anhydride or potassium dichromate 1 to 30 g/ ℓ, pH 2 to 6, bath temperature 20 to 60°C, current density 0.1 to 10 A/d㎡, or potassium dichromate 1 to 30 g/ℓ, zinc sulfate 0.1 to 20 g/ℓ, pH 2 to 6, bath temperature 20 It can be formed by electroplating by immersing the surface in which the first Ni or Ni alloy layer is formed in a plating bath having a current density of 0.1 to 10 A/dm 2 at 60°C.

(2nd Ni layer)

The second Ni layer can be formed by electroplating by immersing the surface in which the release layer is formed in a watt bath or sulfamine bath.

When formed by the electrolytic method, the purity of Ni can be made to a high purity of 99.6% by mass or more.

(Ultra thin copper layer)

The ultra-thin copper layer can be formed, for example, by the method described in JP-A-1-246393.

Specifically, a mixed solution of 10 to 300 g/L of sodium diethylenetriamine pentaacetate and 10 to 100 g/L of copper sulfate hydrochloride is 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 for 1 to 120 seconds at 10 A/dm 2.

(materials)

The composite metal foil according to the present invention is difficult to deteriorate in the peeling function due to high temperature, and even if it is a resin having a high glass transition temperature, it can be easily peeled after being pasted by heat compression. Can be.

(Metal-clad laminate)

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

(Copper-clad laminate)

By removing the second Ni layer on the metal-clad laminate by Ni selective etching, a copper-clad laminate with an ultra-thin copper layer laminated on the substrate can be produced (Fig. 6).

In addition, in the present invention, a composite metal foil can be attached to both sides of the base material to produce a double-sided metal-clad laminate or double-sided copper-clad laminate.

(Printed wiring board)

When the ultra-thin copper layer on the copper-clad laminate is used as a seed layer, a fine pattern circuit can be formed by an additive method (Fig. 7).

Further, the ultrathin copper layer on the copper-clad laminate can also be formed by a circuit using a subtractive method or other method.

(Multilayer printed wiring board)

Further, the formed circuit is harmonized, and the second base material (7(a)) and the composite metal foil according to the present invention are laminated by heat compression on the harmonized circuit to form a second ultrathin copper layer by the composite metal foil according to the present invention. (6(a)) is formed (FIG. 8), the second ultra-thin copper layer and the second substrate are formed with non-perforated holes 12 until the harmonized circuit is reached (FIG. 9), and the inner wall of the non-perforated holes is formed. It is also possible to form a circuit 10(a) by connecting the electroless plating 13 and the electrolytic plating 20 (FIG. 10) to the previously formed circuit.

The circuit 10(b) may be further formed on the second circuit 10(a) in the same way (Fig. 11).

When the copper-clad laminate according to the present invention is laminated and multi-layered, the thickness of the entire multi-layer substrate can be suppressed, and high-density multi-layer substrates can be realized.

In order to make it into a multilayer printed wiring board, it is not limited to the composite metal foil which concerns on this invention, You may laminate|stack the copper foil for conventional printed wiring boards.

Example

Examples and comparative examples of the present invention are shown below, but the present invention is not limited to these.

(Example 1)

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

The copper foil carrier surface was 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 deg. C) to a current density of 5 A/d m 2 Treatment was performed for 30 seconds to form a first Ni layer.

The surface on which the first Ni layer was formed was immersed in a plating bath of 20 g/L potassium dichromate, pH 4.5, and a bath temperature of 30°C, and treated with a current density of 1 A/dm 2 for 2 seconds to form a hydrate complex of Cr. To obtain 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 with a current density of 5 A/d m 2 for 120 seconds to form a second Ni layer.

The surface on which the second Ni layer was formed was immersed in 20 g/L of sodium diethylenetriamine pentaacetate, 30 g/L of copper sulfate pentahydrate, pH 4.0, a bath temperature of 40 DEG C, and a current bath of 2 A/dm2. It was treated for a second to form an ultra-thin copper layer.

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

(Example 2)

A peeling layer composed of a composite consisting of Cr and Zn by dipping in a plating bath of 15 g/L potassium dichromate, 10 g/L zinc sulfate, pH 4.9, and a bath temperature of 30° C. and treated with a current density of 0.5 A/dm 2 for 2 seconds. It was prepared in the same manner as in Example 1 except for forming.

(Example 3)

Nickel sulfate 30 g/L, phosphorous acid 2 g/L, sodium acetate 10 g/L, pH 4.5, immersed in a plating bath at a bath temperature of 30° C., treated with a current density of 2 A/d㎡ for 5 seconds, consisting of Ni and P It was manufactured in the same manner as in Example 1 except that the alloy layer was formed.

(Example 4)

Nickel sulfate 50 g/L, cobalt sulfate 50 g/L, citric acid 30 g/L, pH 4.0, bath temperature 30° C. Immersion in a plating bath, and treated with a current density of 2 A/dm 2 for 2 seconds to form an alloy of Ni and Co It was prepared in the same manner as in Example 1 except that the layer was formed.

(Example 5)

50 g/L of nickel sulfate, 30 g/L of sodium molybdate, 30 g/L of citric acid, pH 9.0, immersed in a plating bath at a bath temperature of 30 DEG C, treated with a current density of 7 A/dm2 for 2 seconds to give Ni and Mo It was manufactured in the same manner as in Example 1 except that the formed alloy layer was formed.

(Example 6)

Nickel sulfate 250 g/L, zinc sulfate 50 g/L, citric acid 30 g/L, pH 4.0, bath temperature 50° C. Immersion in a plating bath, and treated with a current density of 5 A/d㎡ for 2 seconds to form an alloy of Ni and Zn It was prepared in the same manner as in Example 1 except that the layer was formed.

(Example 7)

50 g/L of nickel sulfate, 50 g/L of cobalt sulfate, 30 g/L of sodium molybdate, 30 g/L of citric acid, pH 9.0, immersed in a gold bath at a bath temperature of 30° C. for 2 seconds at a current density of 7 A/d㎡. It was prepared in the same manner as in Example 1 except that an alloy layer made of Ni, Co, and Mo was formed by treatment.

(Examples 8 to 15)

It produced by the method similar to Example 1 except having changed the thickness of the 1st Ni layer, the adhesion amount of a peeling layer, or the adhesion amount of an ultra-thin copper layer as shown in Table 1.

(Example 16)

It was manufactured in the same manner as in Example 1 except that a copper layer was formed by Cu sputtering between the second Ni layer and the ultra-thin copper layer.

(Example 17)

It was manufactured in the same manner as in Example 1 except that a copper layer was formed by Cu deposition between the second Ni layer and the ultra-thin copper layer.

(Comparative Example 1)

It was manufactured in the same manner as in Example 1 except that the release layer was not formed.

(Comparative Example 2)

It was manufactured in the same manner as in Example 1 except that the first Ni layer was not formed.

(Comparative Examples 3 to 8)

It manufactured by the method similar to Example 1 except having changed the thickness of the 1st Ni layer, the adhesion amount of a peeling layer, or the adhesion amount of an ultra-thin copper layer as shown in Table 1.

(Peel strength)

Each composite metal foil of Examples and Comparative Examples was heated for 2 hours and 4 hours in an atmospheric oven heated to 210°C.

Then, it fixed to the flat support plate, and the peeling strength was measured according to the test method of peeling strength in JIS-C6481 (1996) with PT50N manufactured by Minebea Corporation.

Moreover, with respect to the tackiness of peeling, what was peeled was evaluated as ○, and what was not peeled was x.

The metal-clad laminate obtained by peeling the copper foil carrier was immersed in Ni-selective etching solution (Mac Remover NH-1866 Mac Co., Ltd.), and the time (seconds) required to remove the second Ni layer was measured.

Further, on the copper-clad laminate with the second Ni layer removed, an ultra-thin copper layer was used as a seed layer, and a circuit with an ultrafine pattern of L/S=10 µm/10 µm was formed by an additive method, About the formability of the circuit, what formed L/S=10 micrometers/10 micrometers was evaluated by (circle) and what was not formed by x.

Table 1 shows the composite metal foils of Examples and Comparative Examples.

In addition, evaluation of each Example and a comparative example is shown in Table 2.

From the examples and comparative examples, the composite metal foil according to the present invention has a low peel strength even after heating at 210° C. for 4 hours, can be easily peeled, and has an ultrafine pattern of L/S=10 μm/10/10 μm. It has been proved that even a circuit can be preferably formed.

Moreover, in Comparative Example 4 and Comparative Example 6, the thickness of the Ni layer is thick, which is expensive, which is not preferable. In addition, in Comparative Example 6, the removal of the second Ni layer took time and is not preferable.

The composite metal foil according to the present invention is stable even if it is attached at a high temperature to a substrate having a high glass transition temperature because the release function of the release layer is unlikely to deteriorate even at high temperatures, and the metal foil carrier and the first Ni or Ni alloy are stable. The layer and the peeling layer can be easily peeled from the interface of the peeling layer.

Moreover, since the 2nd Ni layer can be removed by selective etching, the copper clad laminated board which laminated|stacked the dense ultra-thin copper layer can be manufactured by a simple method.

Moreover, since the copper layer is very thin in the copper-clad laminate produced using the composite metal foil according to the present invention, when the circuit is formed by the additive method using the ultra-thin copper layer as a seed layer, it is seeded by etching treatment. Since the layer can be removed in a short time and etching to the circuit can be suppressed, even a circuit having an ultrafine pattern such as L/S = 10 µm /10 µm can be preferably formed, and pinholes are less likely to occur Therefore, it is possible to manufacture a printed wiring board having a low circuit disconnection risk, and in the case of multi-layering, when connecting through-holes or non-through-holes by electroless plating and/or electrolytic plating, the ultra-thin copper layer is also plated and thickened. Since it can be suppressed to a minimum, it is possible to suppress an increase in the thickness of the entire substrate in the case of a multi-layer substrate, and to manufacture a high-density multi-layer substrate.

Therefore, it can be said that the present invention is an invention having high industrial applicability.

1: Composite metal foil
2: Metal foil carrier
3: First Ni or Ni alloy layer
4: release layer
5: 2nd Ni layer
6: ultra-thin copper layer
6(a): 2nd ultra-thin copper layer
7: description
7(a): 2nd description
8: Metal-clad laminate
9: copper clad laminate
10: circuit
10(a): 2nd layer circuit
10(b): 3rd layer circuit
12: non-through hole
13: electroless plating
16: Multilayer printed wiring board
20: electrolytic plating
31: primary particle
32: secondary particles

Claims (9)

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, a second Ni layer, and an ultrathin copper layer are disposed on at least one surface of the first Ni or Ni alloy layer. A composite metal foil laminated in order, wherein the primary particle diameter of the copper particles of the ultra-thin copper layer is 10 to 200 nm, the adhesion amount is 300 to 6000 mg/m 2, and the thickness of the second Ni layer is 0.3 to 5 μm. . According to claim 1,
A composite metal foil having a thickness of the first Ni or Ni alloy layer of 0.001 to 5 μm. According to claim 1,
The said peeling layer is a composite metal foil which is a layer containing at least 1 sort(s) of Cr and Zn. According to claim 1,
A composite metal foil having a purity of 99.6% by mass or more of Ni in the second Ni layer. According to claim 1,
A composite metal foil in which a metal layer is formed between the second Ni layer and the ultra-thin copper layer. The insulating resin substrate is heat-compressed and adhered to the ultra-thin 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 carrier are separated by the release layer. Method for producing a metal-clad laminate produced by manufacturing. A method for producing a copper-clad laminate obtained by etching and removing the second Ni layer by using a Ni-selective etching solution for the metal-clad laminate produced by the method according to claim 6. delete delete

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