JP2002176259A - Multilayer printed wiring board and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for a multilayer circuit wiring board, which can thin the circuit board and materialize high-density wiring, and the multilayer circuit board which can be obtained by the manufacturing method for the multilayer circuit wiring board. SOLUTION: A double sided board 7 is manufactured by the process of forming an insulating resin layer 2 on a metal foil 1, the process of forming a via hole 3 on the insulating resin layer 2, the process of forming a first circuit pattern 4 on the insulating resin layer 2 and also forming a conductive layer 5 within the via hole 3, and the process of etching the metal foil 1 thereby forming a second circuit pattern 6. With this double sided board 7 as the base material, this circuit wiring board is multiplayered by a collective stacking method or build-up method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a multilayer printed wiring board and a multilayer printed wiring board obtained by the method for manufacturing a multilayer printed wiring board.

[0002]

2. Description of the Related Art In general, a method for manufacturing a multilayer printed wiring board includes a batch laminating method in which a plurality of double-sided substrates on which a predetermined circuit pattern is formed are laminated and bonded via a prepreg; It is roughly classified into a build-up method in which an insulating resin layer is formed sequentially.

In the batch laminating method, first, a copper-laminated substrate, which is a cloth or nonwoven fabric made of glass or aramid impregnated with an epoxy resin or a phenol resin, is used. A through-hole is formed in the bonded laminate by a drill or a laser, the through-hole is made conductive by copper plating, and then a copper foil is formed into a predetermined circuit pattern by etching to produce a double-sided board. Next, a multilayer printed wiring board is obtained by laminating and bonding the plurality of double-sided substrates thus obtained via a prepreg.

In the build-up method, a copper-clad laminate having a predetermined circuit pattern formed thereon or a multilayer printed wiring board manufactured by a batch lamination method is used as a base material. A resin is applied, and via holes for interlayer connection are formed by photolithography or laser. Next, a predetermined circuit pattern is formed by copper plating, and conduction of the via hole is performed to form a multilayer. By repeating the process of copper plating from the application of such an insulating resin, a multilayer printed wiring board is obtained by further multilayering.

[0005]

However, in recent years, with the rapid spread of mobile phones and portable information terminals, lighter and higher density wiring is increasingly required for printed wiring boards. It is becoming.

However, in the batch lamination method, since the base material to be used is formed of cloth or non-woven fabric, it is not possible to reduce the thickness of the printed wiring board or reduce the diameter of the through-holes for high-density wiring. Have difficulty.

On the other hand, in the build-up method, since there is no cloth or nonwoven fabric in the insulating resin layer, the thickness of the insulating resin layer can be reduced, and the diameter of the via hole can be reduced. Therefore, as compared with the batch lamination method, it is somewhat advantageous to reduce the thickness of the printed wiring board and achieve high-density wiring.
However, even in the build-up method, it is still difficult to reduce the thickness and to achieve high-density wiring in the base portion.

The present invention has been made to solve such problems, and an object of the present invention is to provide a multilayer printed wiring board capable of reducing the weight of a printed wiring board and achieving high-density wiring. It is an object of the present invention to provide a manufacturing method and a multilayer printed wiring board obtained by the method for manufacturing a multilayer printed wiring board.

[0009]

In order to achieve the above object, a method of manufacturing a multilayer printed wiring board according to the present invention comprises the steps of forming an insulating resin layer on a metal foil and forming a via hole in the insulating resin layer. And forming a predetermined circuit pattern on the insulating resin layer by plating, forming a conductive layer in the via hole, and etching the metal foil to form a predetermined circuit pattern. It is characterized by including.

When the double-sided substrate obtained by such a method is used as a base material and multilayered by a batch laminating method or a build-up method, a multilayer printed wiring board capable of reducing the weight of a printed wiring board and achieving high-density wiring. Can be manufactured.

In the method for manufacturing a multilayer printed wiring board according to the present invention, the metal foil may include copper or a copper alloy mainly composed of copper, nickel or a nickel alloy mainly composed of nickel, and nickel and iron as main components. It is preferable that the insulating resin layer is made of either polyimide or stainless steel, and that the insulating resin layer is made of polyimide.

Further, the present invention provides a step of forming an insulating resin layer on a metal foil, a step of forming a via hole in the insulating resin layer, and forming a predetermined circuit pattern on the insulating resin layer by plating. And a multilayer printed wiring board obtained by a method for manufacturing a multilayer printed wiring board, the method including a step of forming a conductive layer in the via hole and a step of etching the metal foil to form a predetermined circuit pattern. It is a thing.

In such a multilayer printed wiring board, it is possible to reduce the weight of the printed wiring board and to achieve high-density wiring, which are required in recent years.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the method for manufacturing a multilayer printed wiring board according to the present invention, first, an insulating resin layer is formed on a metal foil.
To form an insulating resin layer on a metal foil, for example, as shown in FIG.
As shown in (a), first, a metal foil 1 is prepared, the surface of the metal foil 1 is degreased, and then, if necessary, the surface of the metal foil 1 is roughened.

As the metal foil 1, a metal having good electric conductivity can be used. For example, copper or a copper alloy mainly containing copper, nickel or a nickel alloy mainly containing nickel, aluminum or aluminum is mainly used. Aluminum alloys, alloys whose main components are nickel and iron,
It is preferably used. As an alloy containing nickel and iron as main components, it is preferable that nickel and iron are contained in the entire alloy in a total amount of more than 90% by weight, and nickel is contained in the entire alloy. , 20 to 90
% By weight, and more preferably 36 to 85% by weight.

Such alloys containing nickel and iron as main components include commercially available materials having a nickel content of 85% by weight, 78% by weight, 45% by weight, 42% by weight, and 36% by weight. It is commercially available.

In order to improve the bending strength of the completed multilayer printed wiring board, for example, stainless steel having spring properties can be used.

The thickness of the metal foil 1 may be several μm or more. If a high bending strength is required, it depends on the number of the metal foils 1 constituting the multilayer printed wiring board.
A metal foil 1 having a thickness exceeding 100 μm may be used.

Degreasing is performed using a known alkaline or acidic degreasing agent, for example, from room temperature to 60 ° C., unless the metal foil 1 is made of aluminum or an aluminum alloy.
And the treatment may be performed for several minutes. As such a degreasing agent, for example, Methacryl CL-5513
(Manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), OPC Acid Clean 115
(Manufactured by Okuno Pharmaceutical). When the metal foil 1 is made of aluminum or aluminum alloy,
It is preferable to use an acidic to weakly alkaline degreasing agent. As such a degreasing agent, for example, Top Alclean 161 (manufactured by Okuno Pharmaceutical Co., Ltd.) is used.

The surface roughening of the metal foil 1 is performed in order to improve the adhesion with the insulating resin to be formed next.
A commercially available roughening agent can be used. For example, when the metal foil 1 is copper or a copper alloy, CZ-8100 (manufactured by MEC), OPC-400 (manufactured by Okuno Pharmaceutical), or the like is used. The metal foil 1 is roughened by the metal foil 1
In the case where an insulating resin having sufficient adhesiveness with the resin is used, it can be omitted.

Next, as shown in FIG. 1B, an insulating resin layer 2 is formed on one surface of the metal foil 1 thus degreased and, if necessary, roughened using an insulating resin.

As the insulating resin, a commonly used insulating resin for build-up can be used, and any of a liquid and a dry film can be used. When the insulating resin is in a liquid state, for example, the insulating resin layer 2 may be formed by applying the insulating resin to one surface of the metal foil 1, and when the insulating resin is a dry film, For example, the insulating resin layer 2 may be formed by laminating the insulating resin on one side of the metal foil 1.

As such an insulating resin, for example, BL-9700 (manufactured by Hitachi Chemical Co., Ltd.) is used in a liquid state, and BF-8500 (manufactured by Hitachi Chemical Co., Ltd.) is used in a dry film. The main component of the insulating resin is not particularly limited, for example, epoxy, phenol,
Polyimide, BT resin or the like is used. In order to impart flexibility to the multilayer printed wiring board, polyimide is preferably used.

When the insulating resin is polyimide, for example, using Kapton (manufactured by DuPont), Upilex (manufactured by Ube Industries), or the like, an adhesive such as SPB-050A (manufactured by Nippon Steel Chemical Co., Ltd.) is used. Then, the insulating resin layer 2 may be formed by laminating on one side of the metal foil 1, and a solution of a polyamic acid resin is applied on one side of the metal foil 1 and cured by heating to obtain a polyimide. May be formed.

The thickness of the insulating resin layer 2 formed in this manner may be any thickness as long as insulation reliability between the layers can be ensured, and may be appropriately determined, for example, in the range of several μm to several tens μm.

Subsequently, as shown in FIG. 1C, a via hole 3 is formed in the insulating resin layer 2, and the surface of the insulating resin layer 2 is roughened if necessary. The via hole 3 is formed for electrically connecting the layers. The via holes 3 can be formed in the insulating resin layer 2 by a laser method generally used in a build-up method. When the insulating resin layer 2 is formed of a photosensitive resin, it can be formed by a photolithographic method using exposure and development.

The roughening of the insulating resin layer 2 depends on the type of the insulating resin layer 2, but for example, a commercially available desmear agent mainly composed of permanganate is used.

Next, as shown in FIG. 1D, a first circuit pattern 4 is formed on the insulating resin layer 2 by plating, and a conductive layer 5 is formed in the via hole 3. To form the first circuit pattern 4 on the insulating resin layer 2,
There is no particular limitation, and for example, a predetermined circuit pattern may be formed by a known circuit forming method such as a subtractive method, a semi-additive method, and a full-additive method. Simultaneously with this circuit pattern, a conductive layer 5 is formed in the via hole 3 by plating to form a metal foil 1.
And the first circuit pattern 4 are electrically conducted.

For plating, either electrolytic plating or electroless plating may be used, and there is no particular limitation on the main components of the plating, but copper is preferably used. When the first circuit pattern 4 and the conductive layer 5 are formed by electrolytic copper plating, an additive for via filling or the like may be added in order to improve the filling property of plating in the via hole 3. preferable.

The thickness of the first circuit pattern 4 thus formed may be determined as appropriate, for example, in the range of several μm to several tens μm.

Then, as shown in FIG. 1E, the metal foil 1 is etched to form the second circuit pattern 6, thereby obtaining the double-sided board 7. To etch the metal foil 1, for example, a dry film resist is formed on the surface of the metal foil 1 in the same pattern as the second circuit pattern 6,
After etching the metal foil 1, the dry film resist may be removed.

The double-sided board 7 thus obtained is a double-sided board in which the first circuit pattern 4 and the second circuit pattern 6 are electrically connected via the conductive layer 5. A multilayer printed wiring board is obtained by using the double-sided substrate 7 as a base material and forming a multilayer through an adhesive sheet such as a prepreg, or by forming a multilayer on one or both sides of the double-sided substrate 7 by a build-up method. Can be.

The multilayer printed wiring board obtained in this way can realize light and thin and high-density wiring, and can sufficiently respond to recent demands for lighter and thinner printed wiring boards and higher wiring density. Can be.

In the above description, the steps for forming the double-sided substrate 7 may be performed in any order, for example,
The insulating resin layer 2 may be formed in advance, and the insulating resin layer 2 and the metal foil 1 may be laminated. Further, a via hole 3 is formed in the insulating resin layer 2 formed in advance, and the via hole 3 is formed. The formed insulating resin layer 2 and metal foil 1 may be laminated. Further, the etching of the metal foil 1 may be performed after any step as long as the insulating resin layer 2 is laminated.

[0035]

The present invention will be described more specifically with reference to the following Examples and Comparative Examples, but the present invention is not limited to the Examples and Comparative Examples.

Example 1 (Manufacture of double-sided substrate) First, as shown in FIG.
Rolled nickel foil with a thickness of 5 μm (Toyo Seiki Co., Ltd .: Ni-H)
Is cut into a desired size, and a degreasing agent at 60 ° C. (manufactured by Daiichi Kogyo Seiyaku Co., Ltd .: 50 ml / L-methacrylia CL-5513)
For 2 minutes, washed with water and dried to prepare a nickel foil 11. Next, as shown in FIG. 2 (b), photosensitive photovia ink (BL-9700, manufactured by Hitachi Chemical Co., Ltd.) is printed and coated on one side of the nickel foil 11 with a 200 mesh / inch polyester screen. ,
The resultant was dried in a drying oven at 80 ° C. for 40 minutes to form an insulating resin layer 12 having a thickness of about 30 μm.

Subsequently, a film mask was adhered to the insulating resin layer 12, and an ultraviolet ray was applied to the insulating resin layer 12 at an intensity of 2.7 J /
Irradiated with cm ² and heated in a drying oven at 110 ° C. for 20 minutes.
Thereafter, a developer (200 g / L-diethylene glycol monobutyl ether, 5 g / L-sodium hydroxide) at 40 ° C. is sprayed at a pressure of 0.12 MPa for 90 seconds, washed with water, and dried in a drying oven at 160 ° C. for 60 seconds. After curing, the via hole 13 having a diameter of about 50 μm was formed as shown in FIG.

Next, the surface of the insulating resin layer 12 is
° C desmear agent (Meltex: MLB-497)
And then washed with water, treated with a neutralizing agent (MLT-790, manufactured by Meltex) at 60 ° C. for 5 minutes, and washed with water. Further, a plating catalyst (HS-2 manufactured by Hitachi Chemical Co., Ltd.)
02B) for 5 minutes to deposit a plating catalyst. Then, after washing with water, an activating liquid (manufactured by Hitachi Chemical Co., Ltd .; ADP-
601) for 5 minutes, washed with water and dried.

Subsequently, as shown in FIG.
Of 200 ml / L-hydrochloric acid for 2 minutes, washed with water,
Electroless nickel plating (Meltex: B-1)
For 2 minutes, washed with water, and dried to form a nickel plating layer 14 of about 0.1 μm on the surface of the insulating resin layer 12 and the exposed surface of the nickel foil 11.

Next, on the surface of the nickel plating layer 14, a dry film resist 15 (manufactured by Asahi Kasei Corporation: SPG-
152) was laminated at 110 ° C., and a film mask was adhered thereto.
² g, sprayed with 30 g of 10 g / L-sodium carbonate at a pressure of 0.1 MPa for 20 seconds, washed with water, and dried film resist 15 is described below as shown in FIG. The first circuit pattern 16 was formed in a reverse pattern. Thereafter, as shown in FIG. 3F, a copper sulfate plating solution (manufactured by Japan Energy Co., Ltd .: additive 0.2 m)
1 / L-CC-1220) and 2.5 A / dm ²
The first circuit pattern 16 having a thickness of about 10 μm and the via hole 1 are formed by performing copper plating at a current density of 20 minutes for 20 minutes.
3 and a conductive layer 29 were formed.

Subsequently, as shown in FIG.
Of 30 g / L-sodium hydroxide was sprayed at a pressure of 0.1 MPa for 30 seconds to peel off the dry film resist 15 and washed with water. Further, as shown in FIG. 3 (h), a nickel stripper (Top Lip BT, manufactured by Okuno Pharmaceutical Co., Ltd.) at 40 ° C. was spray-treated at a pressure of 0.1 MPa for 10 seconds to form a first circuit pattern 16. Other nickel plating layers 14 were removed, washed with water, and dried.

Next, a dry film resist (SPG-152 manufactured by Asahi Kasei Kogyo Co., Ltd.) was laminated on the surface of the nickel foil 11 at 110 ° C., and a film mask was adhered thereto. ² Irradiation, 30MP 10g / L-sodium carbonate 0.1MP
After spraying at a pressure of 20 seconds for 20 seconds, the film was washed with water to form a dry film resist in the same pattern as the second circuit pattern 17 described below. Then 5
Add 42 Baume iron (II) chloride etchant at 0 ° C. to 0.
After spraying at a pressure of 1 MPa for 60 seconds, the nickel foil 11 is etched by washing with water, and further, 30 g / L-sodium hydroxide at 40 ° C. is 0.1 M
The dry film resist was peeled off by spraying at a pressure of Pa for 30 seconds, washed with water, and then dried to obtain the resist shown in FIG.
As shown in (i), a second circuit pattern 17 having a thickness of about 25 μm is formed, whereby the first circuit pattern 1 is formed.
The double-sided board 18 in which 6 and the second circuit pattern 17 were electrically connected via the conductive layer 29 was manufactured.

(Manufacture of Multilayer Printed Wiring Board) A four-layer printed wiring board was manufactured by building up one layer on each side of the double-sided substrate 18. That is, first,
The surface of the first circuit pattern 16 is sprayed with a copper surface roughening agent (CZ-8100, manufactured by Mec Co.) at a temperature of 35 ° C. for 30 seconds at a pressure of 0.1 MPa, washed with water and then 350 m at 30 ° C.
1 / L-hydrochloric acid at a pressure of 0.1 MPa for 30 seconds,
After washing with water, drying was performed to roughen the surface of the first circuit pattern 16.

Next, as shown in FIG. 4A, a photosensitive photovia ink (BL-9700, manufactured by Hitachi Chemical Co., Ltd.) was applied to the first circuit pattern 16 on a 150 mesh / inch polyester screen. It is printed and dried in a drying oven at 80 ° C. for 40 minutes, and on the first circuit pattern 16,
An insulating resin layer 19 having a thickness of about 30 μm was formed.

As shown in FIG. 4B, a photosensitive photo via ink (BL-9700, manufactured by Hitachi Chemical Co., Ltd.) is printed on the second circuit pattern 17 with a 100 mesh / inch polyester screen. Coated, dried in a drying oven at 90 ° C. for 40 minutes, and on the second circuit pattern 17,
An insulating resin layer 20 having a thickness of about 30 μm was formed.

Subsequently, these insulating resin layers 19 and 20
Adhere a film mask on both sides of the
After irradiating with 2.7 J / cm ² ultraviolet rays and heating in a drying oven at 110 ° C. for 20 minutes, a developing solution (200 g / L-
Diethylene glycol monobutyl ether, 5 g / L-
Sodium hydroxide) at a pressure of 0.12 MPa for 90 seconds, washed with water, and dried in a drying oven at 160 ° C. for 6 seconds.
After curing for 0 minutes, as shown in FIG. 4 (c), via holes 21 and 2 are formed on both sides of these insulating resin layers 19 and 20, respectively.
2 were each formed.

Next, both sides of the insulating resin layers 19 and 20 are coated with a desmear agent (MLT: ML: 70 ° C.) at 70 ° C.
B-497) for 10 minutes, washed with water, treated with a neutralizing agent at 60 ° C. (MLB-790, manufactured by Meltex) for 5 minutes, and washed with water. Further, the coating was treated with a plating catalyst (HS-202B, manufactured by Hitachi Chemical Co., Ltd.) for 5 minutes to attach the plating catalyst. Then, after washing with water, the plate was treated with an activating liquid (manufactured by Hitachi Chemical Co., Ltd .; ADP-601) for 5 minutes, washed with water and dried.

Subsequently, as shown in FIG.
Of 200 ml / L-hydrochloric acid for 2 minutes, washed with water,
Electroless nickel plating (Meltex: B-1)
For about 2 minutes, rinsed with water, and dried to form a nickel plating layer of about 0.1 μm on the surfaces of the insulating resin layers 19 and 20 and the exposed surfaces of the first circuit pattern 16 and the second circuit pattern 17. 23 and 24 were formed.

Next, the nickel plating layers 23 and 24
Dry film resists 25 and 26 (manufactured by Asahi Kasei Kogyo Co., Ltd .: SPG-152) were respectively laminated at 110 ° C., a film mask was adhered to the film, and ultraviolet rays were irradiated at 120 mJ / cm ² with an ultra-high pressure mercury lamp. 30 ° C
5 g / L-sodium carbonate was sprayed at a pressure of 0.1 MPa for 20 seconds, washed with water, and dried film resists 25 and 26 as shown in FIG.
Was formed in a reverse pattern to a third circuit pattern 27 and a fourth circuit pattern 28 described below. Thereafter, as shown in FIG. 5 (f), a copper sulfate plating solution (manufactured by Japan Energy Corporation: additive 0.2 ml / L-CC-12)
20), copper plating is performed for 20 minutes at a current density of 2.5 A / dm ² to form third and fourth circuit patterns 27 and 28 having a thickness of about 10 μm and via holes 21 and 22. The conductive layer 30 and the conductive layer 33 were formed respectively.

Subsequently, as shown in FIG.
Of 30 g / L-sodium hydroxide was sprayed at a pressure of 0.1 MPa for 30 seconds to peel off each of the dry film resists 25 and 26, and washed with water. Further, FIG.
As shown in (h), the third circuit pattern 27 was spray-treated with a nickel stripper (Top Lip BT, manufactured by Okuno Pharmaceutical Co., Ltd.) at 40 ° C. for 10 seconds at a pressure of 0.1 MPa.
And the nickel plating layers 23 and 24 other than the fourth circuit pattern 28 were removed, washed with water, and dried, thereby manufacturing a four-layer printed wiring board.

Example 2 (Manufacture of double-sided substrate) First, as shown in FIG.
5 μm thick copper alloy foil (Yamaha Olin Metal Co .: C-
7025) was cut into a desired size, treated with a degreasing agent (manufactured by Okuno Pharmaceutical Co., Ltd .: 200 ml / L-OPC Acid Clean 115) at 60 ° C. for 2 minutes, and washed with water, to thereby remove the copper alloy foil 31. Prepared.

Next, the copper alloy foil 31 was heated at 30 ° C. for 100 hours.
immersion in 20 ml / L-hydrochloric acid for 20 seconds and a 30 ° C. palladium displacement plating solution (Okuno Pharmaceutical Co., Ltd .: 200 ml / L-
(ICP Axela) for 3 minutes and washed with water. further,
Electroless nickel plating at 60 ° C (Meltex: B
-1) for 2 minutes, washed with water, and dried to form a nickel plating layer 32 of about 0.1 μm on one surface of the copper alloy foil 31 as shown in FIG.

Next, as shown in FIG. 6C, a solution of a polyamic acid resin having the following composition is applied to the surface of the nickel plating layer 32 of the copper alloy foil 31 by a spin coater.
After drying for 15 minutes in a drying oven at 100 ° C., curing for 1 hour in a drying oven under a nitrogen gas atmosphere at 400 ° C.
A thick insulating resin layer 34 was formed.

Polyamic acid resin composition Acid anhydride: 3,3 ′, 4,4′-biphenyltetracarboxylic acid 5 parts by weight Diamine: p-phenylenediamine 5 parts by weight Solvent: N-methyl-2-pyrrolidone 28 parts by weight Subsequently, as shown in FIG. 6D, a via hole 35 having a diameter of about 50 μm was formed using a laser drilling apparatus (model: 5200 manufactured by ESI) under the conditions of a frequency of 4 kHz, an output of 700 mW, and 50 shots / hole.

Next, as shown in FIG. 6E, a sputtering apparatus (SMH-2306RE MH manufactured by Nippon Vacuum Engineering Co., Ltd.)
60-5210) using argon gas, RF power supply 4
Under a condition of 00 W, a chromium sputtered film 36 having a thickness of about 0.03 μm is formed.
Under the condition of W, a copper sputtered film 37 having a thickness of about 0.1 μm was formed.

Next, 2 ml of 100 ml / L sulfuric acid at 25 ° C.
After immersion for 0 second and washing with water, using a copper plating solution for via filling (manufactured by Ebara Ujilite Co., Ltd .: additive 20 ml / L-cubelite VF-MU), as shown in FIG. 7 (f), 2A / dm ² Copper plating was performed at a current density of 30 minutes to form a copper plating layer 38, washed with water, and dried in a drying oven at 100 ° C. for 30 minutes.

Subsequently, a dry film resist 39 (manufactured by Asahi Kasei Corporation; SPG-15) was formed on the surface of the copper plating layer 38.
2) was laminated at 110 ° C., a film mask was adhered thereto, and ultraviolet rays were irradiated at 120 mJ / cm with an ultra-high pressure mercury lamp.
² irradiation, 10 g / L-sodium carbonate at 30 ° C.
After spraying at a pressure of 1 MPa for 20 seconds, the substrate was washed with water, and as shown in FIG. 7G, a dry film resist 39 was formed in the same pattern as a first circuit pattern 40 described below. Thereafter, the copper plating layer 38 and the copper sputtered film 37 are etched by spraying a 42 Baume iron (II) chloride etchant at 50 ° C. at a pressure of 0.1 MPa for 60 seconds.
The chromium sputtered film 36 is etched by being immersed in 2.5% by weight-hydrochloric acid for 2 minutes to form a first circuit pattern 40 having a thickness of about 10 μm and a via hole 35 as shown in FIG. The conductive layer 43 was formed. Further, as shown in FIG. 7 (i), 30 g / L-sodium hydroxide at 40 ° C. was sprayed at a pressure of 0.1 MPa for 30 seconds to remove the dry film resist 39, washed with water, and dried. .

Next, a dry film resist (SPG-152, manufactured by Asahi Kasei Kogyo Co., Ltd.) is applied on the surface of the copper alloy foil 31.
Laminate at 10 ° C, adhere the film mask,
In ultra-high pressure mercury lamp, ultraviolet rays 120 mJ / cm ² was irradiated,
After spraying 10 g / L-sodium carbonate at 30 ° C. at a pressure of 0.1 MPa for 20 seconds, the film was washed with water to form a dry film resist in the same pattern as the second circuit pattern 41 described below. Then 50 ° C
Of the 42 Baume iron (II) chloride etchant was 0.1 M
After spraying for 90 seconds at a pressure of Pa, the copper alloy foil 31 is etched by washing with water,
7 g by spraying 30 g / L-sodium hydroxide at 30 ° C. at a pressure of 0.1 MPa for 30 seconds to remove the dry film resist, washing with water and drying.
As shown in the figure, the second circuit pattern 41 having a thickness of about 10 μm
Thus, a double-sided board 42 in which the first circuit pattern 40 and the second circuit pattern 41 were electrically connected via the conductive layer 43 was manufactured.

(Manufacture of Multilayer Printed Wiring Board) A two-layer printed wiring board was manufactured by laminating and bonding two double-sided boards 42 having different circuit patterns manufactured by the above method. That is, first, as shown in FIG.
2 (one of them has a circuit pattern similar to that of the double-sided substrate 18 of Example 1) prepared at 30 ° C.
Was immersed in a copper surface roughening solution (200 g / L-ammonium persulfate) for 1 minute, washed with water and dried to roughen the surface of each first circuit pattern 40 and each second circuit pattern 41.

Subsequently, a polyimide adhesive 44 (SPB-050A, manufactured by Nippon Steel Chemical Co., Ltd.) is provided between the two double-sided substrates 42.
The two layers were laminated and bonded using a vacuum press at 200 ° C. and 3 MPa for 60 minutes to produce a four-layer printed wiring board as shown in FIG. 8B.

Example 3 A 25 μm-thick rolled SUS3 was rolled from a 25 μm-thick rolled nickel foil (Ni-H, manufactured by Toyo Seikoh foil Co., Ltd.).
A double-sided board was manufactured in the same manner as in Example 1 except that the number of foils was changed to 04 foil (manufactured by Toyo Seikihyo Co., Ltd .: SUS304H-TA). Then, using this double-sided board, the same method as in Example 1 was used. Produced a four-layer printed wiring board.

Example 4 A metal foil to be used was converted from a rolled nickel foil having a thickness of 25 μm (Ni-H) manufactured by Toyo Seiki Co., Ltd. to a rolled 42 alloy foil having a thickness of 25 μm (D-1 manufactured by Sumitomo Special Metals Co., Ltd.). Except for the changes,
A double-sided board is manufactured in the same manner as in the first embodiment, and then, using this double-sided board, a four-sided board is manufactured in the same manner as in the first embodiment.
A multilayer printed wiring board was manufactured.

Example 5 Rolled SUS430 foil having a thickness of 25 μm (manufactured by Toyo Seiki Co., Ltd .: SU
S430H) was cut into a desired size, and a 60 ° C. degreasing agent (Daiichi Kogyo Seiyaku Co., Ltd .: 50 ml / L-methacrylia CL)
-5430) for 2 minutes, washed with water, and dried to prepare a SUS430 foil. Subsequently, Example 2
A double-sided printed circuit board was manufactured in the same manner as in Example 2, and a double-layered printed circuit board was manufactured in the same manner as in Example 2 using this double-sided board.

Example 6 Except that the metal foil used was changed from a rolled SUS430 foil having a thickness of 25 μm (manufactured by Toyo Seiki Co., Ltd .: SUS430H) to a rolled 36 alloy foil having a thickness of 25 μm (manufactured by Sumitomo Special Metals Co., Ltd .: I). A double-sided board was manufactured in the same manner as in Example 5, and then a four-layer printed wiring board was manufactured using this double-sided board in the same manner as in Example 5.

COMPARATIVE EXAMPLE 1 As shown in FIG. 9A, a glass epoxy laminate 51 (MCL-679, manufactured by Hitachi Chemical Co., Ltd.) having a thickness of about 0.13 mm and a copper foil 57 of 18 μm adhered to both sides was prepared. The through hole 52 was formed using a hard drill having a diameter of 0.15 mm.

Next, the mixture was treated with a degreasing agent at 60 ° C. (200 ml / L-OPC Acid Clean 115 manufactured by Okuno Pharmaceutical Co., Ltd.) for 2 minutes, washed with water, and then treated with a 30 ° C. copper roughening solution (200 g
/ L-ammonium persulfate) for 1 minute, washed with water,
5 with a plating catalyst (Hitachi Chemical: HS-202B)
Activated solution (Hitachi Chemical Industries, Ltd .: A
DP-601) for 5 minutes and then washed with water.

Subsequently, the inner wall of the through hole 52 and the surface of the copper foil 57 were dipped in an electroless copper plating solution (CUST-2000, manufactured by Hitachi Chemical Co., Ltd.) Was formed and washed with water.

Further, as shown in FIG. 9B, a copper sulfate plating solution (manufactured by Japan Energy Co., Ltd .: additive 0.2 ml /
L-CC-1220), copper plating at a current density of 2.5 A / dm ² for 20 minutes, washing with water and drying.
A copper plating layer 53 was formed to make the through hole 52 conductive.

Subsequently, a dry film resist (SPG-152 manufactured by Asahi Kasei Kogyo Co., Ltd.) was laminated on both surfaces at 110 ° C., a film mask was adhered, and ultraviolet rays were irradiated at 120 mJ / cm ² with an ultra-high pressure mercury lamp. 30 ℃ 1
0 g / L-sodium carbonate at a pressure of 0.1 MPa for 20
After spraying for 2 seconds, the film was washed with water to form a dry film resist in the same pattern as the circuit pattern to be formed. After that, the copper plating layer 53 and the copper foil 57 are etched by spraying a 42 Baume iron (II) etchant at 50 ° C. at a pressure of 0.1 MPa for 60 seconds, followed by washing with water.
0.1 g of 30 g / L sodium hydroxide at 40 ° C.
9 for 30 seconds by spraying to remove the dry film resist, washing with water and drying.
The thickness of the circuit pattern is about 26 μm as shown in FIG.
A thick double-sided substrate 54 was manufactured.

Evaluation The dimensions of the double-sided substrates of Examples 1 to 6 and Comparative Example 1 were about 120 mm in length and about 100 mm in width, all of which had the same circuit pattern.

Comparing the weights of these double-sided boards, the weight of the double-sided board of Comparative Example 1 is about 4.6 g,
The weight of the double-sided board of Example 1 is about 2.9 g, the weight of the double-sided board of Example 2 is about 3.1 g, the weight of the double-sided board of Example 3 is about 3.0 g, and both sides of Example 4 The weight of the substrate was about 3.0 g, the weight of the double-sided board of Example 5 was about 3.1 g,
The weight of the double-sided board of Example 6 was about 3.2 g, which was about 35% lighter than Comparative Example 1.

When comparing the thicknesses of these double-sided substrates, the thickness of the double-sided substrate of Comparative Example 1 is about 152 μm, while the thickness of the double-sided substrate of Example 1 is about 64 μm, and the double-sided substrate of Example 2 is Is about 53 μm, the thickness of the double-sided board of Example 3 is about 64 μm, the thickness of the double-sided board of Example 4 is about 64 μm, and the thickness of the double-sided board of Example 5 is about 5 μm.
The thickness of the double-sided substrate of Example 6 was about 53 μm, which was less than half the thickness of Comparative Example 1.

Therefore, by using the double-sided substrate manufactured by the method for manufacturing a multilayer printed wiring board according to the present invention as a base material and performing multilayering by a batch lamination method or a build-up method,
It has been found that the weight and the thickness of the multilayer printed wiring board can be reduced sufficiently.

In the case of the double-sided board of Comparative Example 1, the electrical connection of the circuit pattern formed on both sides is about 150 mm in diameter.
On the other hand, in the case of the double-sided substrates of the first to sixth embodiments, the processing is performed via the through hole 52 having a diameter of about 50 μm. Therefore, in the double-sided boards of Examples 1 to 6, since the hole diameter for conducting the circuit patterns formed on both sides can be reduced, the diameter of the via hole pad can be reduced, and high-density wiring is possible. It turned out to be.

[0075]

As described above, according to the method for manufacturing a multilayer printed wiring board of the present invention, it is possible to manufacture a multilayer printed wiring board that is lightweight, light and thin and capable of high-density wiring. A multilayer printed wiring board manufactured by the method for manufacturing a multilayer printed wiring board can sufficiently respond to recent demands for lighter and thinner printed wiring boards and higher density wiring.

[Brief description of the drawings]

FIGS. 1A and 1B are cross-sectional views of main parts showing respective steps of a method for manufacturing a multilayer printed wiring board according to the present invention, wherein FIG. 1A is a step of preparing a metal foil, and FIG. Forming a layer; (c) forming a via hole in the insulating resin layer; and (d) forming a first circuit pattern in the insulating resin layer by plating and forming a conductive layer in the via hole. (E) shows a step of etching the metal foil.

FIGS. 2A and 2B are cross-sectional views of main parts showing respective steps for manufacturing a double-sided board in Example 1, wherein FIG. 2A is a step of preparing a nickel foil, and FIG. (C) forming a via hole in the insulating resin layer, (d) forming a nickel plating layer on the surface of the insulating resin layer and the exposed surface of the nickel foil, (e). ) Shows a step of laminating a dry film resist on the surface of the nickel plating layer.

FIG. 3 is a cross-sectional view of a main part showing respective steps for manufacturing a double-sided board in Example 1, following FIG. 2;
(F) is a step of forming a first circuit pattern, (g)
Is a step of removing the dry film resist, (h)
Is a step of removing the nickel plating layer, and (i) is a step of removing the second plating layer.
The step of forming the circuit pattern of FIG.

FIGS. 4A and 4B are cross-sectional views of essential parts showing respective steps for manufacturing a four-layer printed wiring board in Example 1. FIGS.
Is a step of forming an insulating resin layer on the first circuit pattern, (b) is a step of forming an insulating resin layer on the second circuit pattern, and (c) is a via hole in each insulating resin layer. (D) shows the step of forming a nickel plating layer on the surface of each insulating resin layer and on the exposed surfaces of the first circuit pattern and the second circuit pattern.

5 is a fragmentary cross-sectional view showing each step of manufacturing a four-layer printed wiring board in Example 1, wherein FIG. 5 (e) shows a surface of each nickel plating layer; A step of laminating each dry film resist,
(F) is a step of forming a third circuit pattern and a fourth circuit pattern, (g) is a step of removing each dry film resist, and (h) is a step of removing each nickel plating layer. Show.

FIGS. 6A and 6B are cross-sectional views of main parts showing respective steps for manufacturing a double-sided board in Example 2, wherein FIG. 6A is a step of preparing a copper alloy foil, and FIG. A step of forming a nickel plating layer on one side, (c) a step of forming an insulating resin layer on the surface of the nickel plating layer, (d) a step of forming a via hole in the insulating resin layer, and (e) And a step of forming a chromium sputtered film and a copper sputtered film on the surface of the insulating resin layer and the exposed surface of the copper alloy foil.

FIG. 7 is a fragmentary cross-sectional view showing each step of manufacturing the double-sided board in Example 2, following FIG. 6;
(F) is a step of forming a copper plating layer, (g) is a step of laminating a dry film resist on the copper plating layer, (h) is a step of forming a first circuit pattern,
(I) shows a step of removing the dry film resist. (J) shows a step of forming a second circuit pattern.

8A and 8B are cross-sectional views of main parts illustrating respective steps for manufacturing a four-layer printed wiring board in Example 2, and FIG.
Shows a step of preparing two double-sided boards, and (b) shows a step of laminating and bonding a polyimide adhesive between the two double-sided boards.

FIGS. 9A and 9B are cross-sectional views of main parts showing respective steps for manufacturing a double-sided board in Comparative Example 1, in which FIG. 9A is a step of forming through holes in a glass epoxy laminate, and FIG.
Shows a step of forming a copper plating layer on the inner wall of the through hole and the surface of the glass epoxy laminate, and (c) shows a step of forming a circuit pattern on both surfaces.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 metal foil 2 insulating resin layer 3 via hole 4 first circuit pattern 5 conductive layer 6 second circuit pattern 7 double-sided board

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Atsushi Tanaka, Inventor Atsushi 1-2-1, Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation (72) Inventor Satoshi Tanigawa 1-1-2, Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation (72) Inventor Hirofumi Fujii 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation (72) Inventor Kazunori Mune 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko F term (reference) 5E346 CC10 CC32 CC37 DD03 DD12 DD25 DD48 EE33 GG15 GG22 HH22 HH23 HH25

Claims (4)

[Claims] A step of forming an insulating resin layer on a metal foil; a step of forming a via hole in the insulating resin layer; and forming a predetermined circuit pattern on the insulating resin layer by plating; A method of forming a conductive layer therein, and a step of etching the metal foil to form a predetermined circuit pattern. 2. The method according to claim 1, wherein the metal foil is any one of copper, a copper alloy mainly containing copper, nickel, a nickel alloy mainly containing nickel, an alloy mainly containing nickel and iron, and stainless steel. The method for manufacturing a multilayer printed wiring board according to claim 1. 3. The method according to claim 1, wherein the insulating resin layer is made of polyimide. 4. A step of forming an insulating resin layer on a metal foil, a step of forming a via hole in the insulating resin layer, and forming a predetermined circuit pattern on the insulating resin layer by plating, A multilayer printed wiring board obtained by a method for manufacturing a multilayer printed wiring board, comprising: a step of forming a conductive layer therein; and a step of etching the metal foil to form a predetermined circuit pattern.