JPH01295494A - Manufacture of multilayer printed board - Google Patents

Abstract

PURPOSE:To prevent the generation of hollows, by using an inner layer plate obtained by a method wherein, after a black or brown copper oxide surface is formed, said copper oxide surface is treated by dilute solution of specified cyanato compound, and dried. CONSTITUTION:For an inner layer plate wherein printed wiring network for the inner layer is formed for an intermediate layer, the following is used; a copper foil surface is chemically oxidized, a black or brown copper oxide surface is formed, and the copper oxide foil surface is treated by dilute solution of cyanato compound having two or more cyanato radicals in a molecule, thereby obtaining the inner layer plate to be used after drying. As the cyanato compound having two or more cyanato radicals in a molecule, the following are used; for example, 1,3- or 1,4-dicyanatobenzene, 1,3,5-tricyanatobenzene, 1,3- 1,4- 1,6- 1,8- 2,6- or 2,7-dicyanatonaphthalene, and 1,3,6-tricyanatonaphthalene. Thereby, the generation of hollows can be prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a method for manufacturing a multilayer printed wiring board, which is characterized by a method for treating a copper foil surface of a printed wiring board serving as an intermediate layer (inner layer). , the halo is reduced or eliminated due to the copper oxide exposed on the hole wall being dissolved by the action of an acidic aqueous solution during the manufacturing process of a multilayer printed wiring board.

[Conventional technology and its problems]

In a multilayer printed board, a method for improving the multilayer adhesion of an inner layer board on which a printed wiring network is formed is to use copper foil that has been chemically or electrochemically treated to have roughness on both sides. A method of using a printed wiring network for the inner layer, and then forming a copper oxide film on the surface of the copper foil by chemical treatment; After forming a printed wiring network for the inner layer, a glossy copper foil is used. A method of treating the surface with a silane coupling agent is known.

However, the method of using copper foil that has been textured on both sides in advance has the disadvantage that the copper foil is expensive, and that when a printed wiring network is formed by etching the copper foil, the side surfaces of the etched copper foil (etched The disadvantage is that there is no treatment to improve the adhesive strength, and the method of treating the glossy copper foil surface with a silane coupling agent has the disadvantage that the adhesive strength tends to be insufficient. . There are also various methods of oxidizing the copper foil surface, but many of them lack adhesive strength depending on the type.

For this reason, for printed wiring boards for intermediate layers, after forming a printed wiring network for inner layers on one or both sides of a glossy copper-clad laminate, a layer of NaOIt and sodium hypochlorite or the like is usually used. immersed in a heated concentrated alkaline aqueous solution,
Thereafter, it is washed with water and dried to form a brown or black film made of cuprous oxide or cupric oxide, which is used for its adhesive strength and economic efficiency. However, this copper oxide film, particularly cupric oxide, has the disadvantage that it easily dissolves in acidic aqueous solutions such as hydrochloric acid and sulfuric acid. For this reason, when making small holes in a laminated multilayer board and performing a through-hole plating process, electroless plating process, or subsequent electrolytic plating process, the copper oxide film exposed on the hole wall is dissolved by the acidic liquid. A "halo" phenomenon occurs. Halos cause a decrease in the reliability of printed wiring boards, such as insulation properties.

[Means for solving problems]

The inventors of the present invention have conducted extensive research into an easy method that takes advantage of the excellent adhesion and economic efficiency of brown or black copper oxide treatment and also significantly prevents the formation of halos, and as a result, they have discovered a polyfunctional cyanato compound treatment. The present invention has now been completed.

That is, in the method of manufacturing a multilayer printed wiring board, the present invention involves chemically oxidizing the copper foil surface of an inner layer board on which a printed wiring network used as an intermediate layer is formed to form a black or brown copper oxide surface; treating the copper oxide surface with a dilute solution of a cyanato compound having two or more cyanato groups in the molecule,
This is a method for manufacturing a multilayer printed wiring board characterized by using a dried inner layer board.

The configuration of the present invention will be explained below.

The multilayer printed wiring board of the present invention is an inner layer board on which an inner layer printed wiring network used for the above-mentioned intermediate layer is formed, and after chemically oxidizing a copper foil surface to form a black or brown copper oxide surface, In addition to treating the surface of the copper oxide foil with a dilute solution of a cyanato compound having two or more cyanato groups in the molecule and drying it, we also use inner layer plates and multilayer adhesives used in multilayer lamination molding. Conventionally known materials and methods can be used, such as prepreg used for forming the outer layer, prepreg for forming the outer layer, laminated materials such as copper foil or single-sided copper-clad laminate, and laminated molding methods, and are not particularly limited. be.

Such laminated materials include E glass, S glass, D glass,
Various glass woven fabrics such as quartz glass, inorganic woven fabrics such as alumina paper: Fully aromatic polyamide, polyimide, fluororesin, polyphenylene sulfide, polyetheretherketone, polyetherimide, and other super heat-resistant resins. Woven fabric: Woven fabric using composite yarn using the above-mentioned inorganic fibers and super heat-resistant resin fibers; Woven fabric such as a suitable combination of the above is used as a reinforcing base material, and bisphenol A type, novolac type , epoxy resins such as halogenated bisphenol A type, halogenated novolac type, and other trifunctional or higher polyfunctional epoxy compounds;
Cyanate ester resins, typically cyanate resins, cyanate ester-epoxy resins, cyanate ester-maleimide-epoxy resins; Maleimide resins whose main component is functional amines; prepregs made of heat-resistant thermoplastic resins and resins made of compositions of thermoplastic resins and thermosetting resins; electrolytic copper foils and rolled copper. Copper foil such as foil, double-sided or single-sided copper-clad laminate made by laminating and molding copper foil and prepreg, inner-layer printed wiring board (inner-layer printed wiring board) with inner-layer printed wiring network formed on one or both sides of copper-clad laminate board) is exemplified. Examples of the lamination molding method include conventional hot plate press, hot plate vacuum press, and autoclave molding.

The method of forming a brown or black copper oxide film on the inner layer plate of the present invention is known, and is usually performed after polishing and cleaning the copper foil surface of the inner layer plate, and then pre-etching with an aqueous solution such as copper chloride or ammonium persulfate. , treatment with an oxidizing aqueous solution. Here, the oxidizing aqueous solution and treatment conditions are specifically exemplified below, but are not limited thereto, and known methods can be used.

■, Sodium hydroxide (Na011 (15g/1
))/Sodium hypochlorite (NaC10z (31g)
/ (1)) / Sodium phosphate (15g#), 70
~100°C, 0.5-10 minutes.

■, Copper sulfate (50g/l)/sodium chloride (2
00g, #), 40-80°C, 3-15 minutes.

■, acetic acid (20g/l)/ammonium chloride (20g/l)
1)/Copper acetate (10g #, 30~80℃, 1~
10 minutes.

■, Copper acetate (10g/l)/Copper sulfate (24g/II
)/Barium sulfide (24g/12)/Ammonium chloride (24g/j2), 40~50℃, 1~
10 minutes.

■, Copper sulfate (25g/ (1) / Nickel sulfate (25
g/12)/potassium chlorate (25g/l, 7
0-90°C, 1-10 minutes.

After cleaning the inner layer plate treated with black or brown as above,
In the present invention, an inner layer plate is used, which is treated with a dilute solution of a cyanato compound having two or more cyanato groups in one molecule and dried to form a cyanato compound layer on the copper oxide surface.
Reduce or eliminate the occurrence of "halo".

Here, preferred cyanato compounds having two or more cyanato groups in one molecule of the present invention are represented by the following general formula (
1); % formula % (1) (m in the formula is an integer of 2 or more and usually 5 or less, R is an aromatic organic group, and the cyanato group is bonded to the aromatic ring of the organic group. It is a compound represented by Specific compounds include 1.
3- or 1,4-dicyanatobenzene, 1.3.5-
) Lecyanatobenzene, 1.3-, 1.4-, 1.6-
, 1.8-, 2.6- or 2.7-dicyanatonaphthalene, 1.3.6-) dicyanatonaphthalene, 4.4'
-dicyanatobiphenyl, bis(4-cyanatophenyl)methane, 2,2-bis(4-cyanatophenyl)propane, 2.2-bis(3,5-dichloro-4=cyanatophenyl)propane, 2.2 -bis(3,5-dimethyl-4-cyanatophenyl)propane, 2,2-bis(3
, 5-dibromo-4-cyanatophenyl)propane, bis(4-cyanatophenyl)ether, bis(4-cyanatophenyl)thioether, bis(4-cyanatophenyl)sulfone, tris(4-cyanatophenyl) ) phosphite, tris(4-cyanatophenyl) phosphate, and a cyanate ester obtained by the reaction of a polycarbonate oligomer containing terminal OH groups with cyanide halogenated (USP-4026913), /borac and halogenated Cyanic acid esters obtained by reaction with cyanide (USP-4022755, USP-34480
79), and styryl-styryl obtained by reacting polyhydroxy-styryl-pyridine etc. with cyanogen halide.
Pyridine-cyanate (5P-4578439) and the like. In addition to these, Special Publications No. 41-1928, No. 43-18468, No. 44-4791, No. 45-117
12, 46-41112, 47-26853, JP-A-51-63149, USP-3553244,375
5402, 3740348, 3595900, 3694
Examples include cyanate esters described in 410 and 4116946.

In addition, sym is formed by simply heating the above-mentioned polyfunctional cyanate ester or by polymerizing it in the presence of a catalyst to trimerize the cyanide groups in the cyanate ester.
-) Number average molecular weight 300 to 6.0 with riazine ring
The cyanato compound can be used as a prepolymer of 00 or as a prepolymer with an amine, or as a mixture with an epoxy resin, a silane tapping agent, etc.

However, the black or brown copper oxide film used in the present invention has fine pores, and it is preferable to form a cyanato compound film homogeneously over the entire surface including the pores in the film, and furthermore, As for the thickness of the layer to be adhered to the printed wiring board, monomers or those of low molecular weight are preferable because they are sufficiently effective even at a thickness of 11 or less.

As the solvent for the above cyanato compound, any known solvent for cyanato compounds can be used; specifically, ketones such as acetone and methyl ethyl ketone; aromatic hydrocarbons such as benzene, toluene, and xylene; and chloride. Examples include methylene, tomethylpyrrolidone, vinyl acetate, acetonitrile, ethyl acetate, ethylene glycol dimethyl ether and other various solvents.

There is no particular limit to the concentration when it is made into a dilute solution, but
It is preferably in the range of 0.001 to 3.0% by weight, and known catalysts such as organic metal salts and other cyanato compounds may be used in combination.

The method for treating the inner layer plate with the above-mentioned dilute solution of the cyanato compound may be any known method, such as immersing the inner layer plate in the above-mentioned dilute solution, spraying the inner layer plate with the dilute solution,
Examples include methods of applying with a brush, coater, etc.

The treated inner layer plate is dried by a known method such as air drying or heating to remove at least the solvent, thereby obtaining the treated inner layer plate of the present invention.

〔Example〕

The present invention will be explained below with reference to Examples.

Note that the percentages in the examples are based on weight.

Example 1 After forming a model pattern on both sides of a double-sided copper-clad glass epoxy laminate with a thickness of 1n++n and a copper foil thickness of 70mm by a known etching method, NaOH (15g/l)/sodium hypochlorite (31g/β) )/sodium phosphate (
A black copper oxide treated inner layer plate was obtained by treating with an aqueous solution of 15 g/l) at 95°C for 5 minutes, washing with water, and drying at 130°C for 30 minutes.

This inner layer plate was coated with a concentration of 2,2-bis(4-cyanatophenyl)propane of 0.05.0, 1.0.5.1, respectively.
After immersion in 0°3.0% methyl ethyl ketone solution,
A treated inner layer plate was obtained by drying at 130°C for 30 minutes.

Black copper oxide treatment and glass epoxy prepreg (resin content 52%, thickness 0.1mm
) Three sheets of electrolytic copper foil with a thickness of 18 mm were stacked and laminated for 2 hours at a temperature of 175° C. and a pressure of 40 kg/caf to form a 4-layer shield plate, and then cooled, and then the hole diameter was 0.4 mm, 8 mm. 1,0,000 r, p, m, 20-/rotation condition
00 holes were drilled at intervals of 2.54 mm.

This perforated four-layer shield plate was immersed in a 4N HCI aqueous solution for 5 minutes, and the halo around the hole in the inner layer was observed and its length was measured.

Also, take a 5cm square piece of the 4-layer shield plate with holes, and
After steam treatment (PCT) at 1°C and 2 atm for 3 hours, a test was conducted by immersing it in solder at 260°C for 30 seconds.

The results are shown in Table 1.

Table 1 Example 2 In Example 1, a double-sided copper-clad glass cyanate ester-maleimide-epoxy resin laminate (manufactured by Mitsubishi Gas Chemical GL, HL 810) was used as the inner layer board.
A glass cyanate ester-maleimide-epoxy resin prepreg (manufactured by Mitsubishi Gas Chemical Co., Ltd., GHPL 810) was used as a prepreg for multilayer adhesion, and a dilute solution of a cyanato compound for surface treatment in which 1,4-dicyanatobenzene was dissolved was used. using multilayer lamination molding conditions at a temperature of 200
The procedure was the same except that the temperature was changed to 2 hours. The results are shown in Table 2.

Table 2 [Operations and Effects of the Invention] From the detailed description and examples above, the multilayer printed board manufactured by the manufacturing method of the present invention is manufactured using a plating solution in the through-hole plating process for establishing electrical continuity between the printed wirings of the multilayer board. A multilayer printed wiring board with excellent reliability, as the occurrence of "halos", which tend to cause defects such as electrical short circuits due to the dissolution of brown or black copper oxide, is greatly reduced or completely eliminated. It is of extremely high industrial significance.

Patent applicant: Mitsubishi Gas Chemical Co., Ltd.

Claims (1)

[Claims] In the manufacturing method of multilayer printed wiring boards, after chemically oxidizing the copper foil surface of the inner layer board that forms the printed wiring network used as the intermediate layer to form a black or brown copper oxide surface, two or more oxides in one molecule are formed. 1. A method for producing a multilayer printed wiring board, comprising treating the copper oxide surface with a dilute solution of a cyanato compound having a cyanato group and drying the inner layer.