JPH02188987A - Material for wiring board and manufacture thereof - Google Patents

Abstract

PURPOSE:To improve fine wiring formation properties by forming a metal layer on at least single surface of an insulation film and laminating it with an insulation resin base in one piece. CONSTITUTION:Polyethylene, etc., is used as a material of an insulation film 1 and then a metal layer 2 such as copper is formed on it by applying the resistance heating deposition method. the electron beam deposition method, the ion plating method, the sputtering method, etc. Then, when the metal layer 2 is formed only on the single surface of the insulation film 1, a required number of prepregs 3 obtained by dipping a glass cloth, etc., into epoxy resin, thus resulting in a semi-cured state, are placed on a surface where no metal layer 2 is formed, heating/press forming is performed to obtain a laminated body. A metal layer 2 of a required part is exposed on the laminated plate with metal layer thus obtained and plating resist is formed at other parts and are allowed to contact a chemical etching liquid. Then, it is eliminated and subjected to circuit machining to allow a wiring board to be formed. Thus, a metal can be formed without affecting an insulation material.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for manufacturing materials used in high-density wiring boards.

(Prior Art) One of the wiring formation methods for high-density wiring boards is a semi-additive method. This involves forming a metal layer such as copper on the entire surface of the board, and finally forming a resist on the parts that will not become conductors. Then, a thick conductor pattern is plated on the exposed metal layer, and after removing the resist, This is a wiring formation method that removes metal from unnecessary parts. In high-density wiring boards, miniaturization of lines/spaces has become an unavoidable trend. In order to facilitate this miniaturization in the semi-additive method, it is desirable to reduce the thickness of the metal layer formed on the entire surface of the substrate (hereinafter referred to as the base metal layer). This is because the thicker the etching, the greater the amount of etching to be performed in the final stage, which tends to cause side etching of lines that should remain as conductors, making it more likely that lines will be chipped or disconnected. There are the following three conventional methods for carrying out this semi-additive method on a normal laminated substrate such as a glass cloth-epoxy substrate.

One method is to use a copper-clad laminate obtained by laminating copper foils. Currently, some of the thinnest copper foils are called ultra-thin copper foils, which are made by plating copper to a thickness of about 5 μm on an aluminum carrier with a thickness of 10 μm or more.
There is GTC-5μm foil manufactured by File ■.

The second method is to coat the laminate with an adhesive containing a rubber component, roughen the adhesive, and then form a metal layer by direct plating.

A third method is to directly form a metal layer on the laminate using a vacuum film forming method such as a resistance heating evaporation method, an electron beam evaporation method, or a standby method.

(Problem to be solved by the invention) When using this copper foil with an aluminum carrier, after laminating it together with the prepreg, only the aluminum is dissolved and removed, and circuit processing is performed as a copper-clad laminate. In this method, it is necessary to selectively etch only aluminum, which requires the installation of a new dedicated etching device and careful work management during etching.

Furthermore, since the carrier is made of aluminum, the copper foil tends to wrinkle or fold when handled, making the work difficult.

The method of coating a laminate with an adhesive containing a rubber component, roughening the adhesive, and then forming a metal layer directly by plating has limited applications because the adhesive has insufficient heat resistance and insulation properties. has been done.

These methods, in which a metal layer is directly formed on a laminate using a vacuum film forming method such as resistance heating evaporation, electron beam evaporation, or stamper method, expose the laminate to a reduced pressure atmosphere, making it difficult to use with ordinary glass. Cloth epoxy laminates and the like have the disadvantage that volatile components such as moisture remaining at the interface between the glass cloth and the epoxy resin, which are the constituent materials thereof, evaporate under reduced pressure, and the laminate tends to peel between the eyebrows.

The present invention provides a material for a wiring board that has excellent ability to form fine wiring and a method for manufacturing the same.

(Means for Solving the Problems) The present invention is a wiring board material comprising an insulating film 1, a uniform metal N2, and an insulating resin base material 3, as shown in FIG.

As shown in FIGS. 2(a) and 2(b), the manufacturing method includes depositing metal N2 on at least one side of the insulating film 1 by resistance heating evaporation, electron beam evaporation, ion plating, or sputtering. There is a method of forming and laminating and integrating with the insulating resin base material 3.

The material of this insulating film 1 may be polyethylene, polypropylene, polyester, nylon, polyvinyl alcohol, polyvinyl chloride, polyvinyldene chloride, polystyrene, polymethylpentene, polybutene, polycarbonate, polysulfone, polyimide, fluororesin, etc.
or a combination of these can be used.

Before forming the metal, the surface of the insulating film is subjected to wet etching treatment, sandblasting treatment, brushing treatment, VU10ff treatment,
Corona discharge treatment, plasma treatment, etc. or a combination of these treatments may be performed.

Further, the thickness of these films is not particularly limited, but any thickness that can be easily wound into a roll is suitable for mass production in vacuum film formation. As the vacuum film forming method, a resistance heating evaporation method, an electron beam evaporation method to an ion plating method, a sputtering method, etc. can be applied.

Further, the material of the metal layer 2 formed on the surface of the insulating film l is preferably copper, but may also be nickel, chromium, aluminum, titanium, palladium, tin, metal base, platinum, or a combination of two or more of these metals. May be used.

Moreover, these metal layers 2 can be formed as shown in FIG. 3(a) if necessary.
It may be formed on both sides as shown in FIG.

After forming the metal layer 2, the insulating film 1 is cut into the desired size.
to cut. When the metal layer 2 is formed on only one side of the insulating film 1, the required number of semi-cured prepregs made of glass cloth impregnated with epoxy resin are placed on the side where the metal layer 2 is not formed. Then, heat and pressure molding is performed in the same manner as in a normal laminate manufacturing method to obtain a laminate. In the above case, after molding, it becomes a single-sided metal laminate.

In order to obtain a double-sided metal laminate, a single-sided metal-attached film may be placed on both sides of the required number of prepregs, and then heated and pressure molded.

Here, in addition to glass cloth, paper base material, glass nonwoven fabric, quartz cloth, Kevlar cloth, etc. can be used as prepreg materials, and in addition to epoxy resin, phenol resin, polyester resin, polyimide resin, etc. Resin, fluororesin, etc. can be used.

Further, as the prepreg, a resin alone without a core material such as glass cloth may be used.

Moreover, it is also possible to make a laminate with an inner layer circuit by sandwiching a circuit-formed substrate between prepregs and stacking them not only using prepregs during lamination.

In the thus obtained metal layer-attached laminate, the metal layer 2 is exposed in necessary parts, a plating resist is formed in other parts, plating metal is deposited, and the plating resist is removed to expose the metal layer 2. It is possible to manufacture a wiring board by contacting the substrate with a chemical etching solution, removing it, and processing the circuit.

Taking a double-sided copper material laminate as an example, as shown in Figure 3 (C), after drilling holes with an NC drill machine, etc., a plating catalyst is attached to the surface of the substrate and the inner wall of hole 4 using the usual method. After that, a plating resist 5 is formed on the portions that will not ultimately form a circuit. Before forming the plating resist 5, electroless copper plating may be performed if necessary; after forming the resist 5, electroless copper plating, electrolytic copper plating, or a combination of electroless copper plating and electrolytic copper plating Then, the conductor is thickened as shown in FIG. 3(d). Thereafter, as shown in FIG. 3(e), the resist 5 is peeled off and unnecessary copper is etched. Alternatively, after thickening the conductor with copper plating, solder or nickel plating may be applied, the resist may be peeled off, and the copper in unnecessary portions may be etched.

The above is an example of a semi-additive circuit formation method.

As a wiring formation method for a double-sided copper material laminate, a method can also be applied in which after drilling holes, a copper layer of a desired thickness is formed on the entire surface of the board, and unnecessary portions are etched.

(Function) According to the present invention, since metal is formed to a required thickness on a film and a laminate is manufactured using the film, unnecessary etching of the aluminum carrier, which was a problem with the conventional technology, is avoided. etc., and there is no need to install new equipment or special etching technology related to aluminum carriers. Furthermore, since the metal is directly formed on the film using a vacuum film forming apparatus, there is no need for adhesives that have problems with heat resistance or insulation. Furthermore, since there is no need to place the laminated plate in a vacuum apparatus, which has conventionally caused problems due to volatile components, metal can be formed without adversely affecting the insulating material.

Example First, a polyimide film, Kapton-100V (trade name, manufactured by DuPont Toshi Co., Ltd.) having a thickness of 25 μm is prepared. One side of this polyimide film was coated with a film-forming rate of 0.2 μm/sin using an ordinary sputtering device to a thickness of 1
Copper 2 of μm is formed.

Next, multiple sheets of epoxy prepreg E-6 with glass cloth were placed in contact with the film surface of the polyimide film with a copper layer.
7 (Hitachi Chemical Co., Ltd., product name), and set the temperature to 1.
Pressing was performed at 70° C. and a pressure of 40 kg/di for 1 hour to obtain a laminate.

Thereafter, a through hole 4 is drilled in a desired portion using an NC drill machine, and a plating catalyst is adhered to the surface of the laminate and the inner wall of the through hole using a conventional method. Then, a dry film resist, Photoc 5R-3000 (trade name, Hitachi Chemical Co., Ltd.) is bonded to the surface of the laminate, exposed to light, and developed to form a plating resist 5 on the portions that will not become conductors.

After this, it was immersed in the following electroless copper plating solution for 20 hours,
An electroless copper plating layer 6 is formed.

〔composition〕

Cu5Oa・5HtO: 10g/IEDTA
4Na: 4Gg/J37% CHxO
: 3rnl/1 [Conditions] PH: iz, 3 Plating solution temperature: 70°C Next, the substrate was immersed in a methylene chloride solution to remove the plating resist, and then immersed in an ammonium persulfate aqueous solution to sputter fR1 of the insoluble part. remove.

Thereafter, if necessary, a dry film resist Photec 5R-1000 (trade name, Hitachi Chemical Co., Ltd.) is bonded to the substrate, exposed and developed to form a permanent resist in desired areas.

(Effect of the invention) The following effects can be achieved by the present invention.

1) Since a thin metal layer can be formed on a laminate without unnecessary carriers, a high-density wiring board can be manufactured with a simple process.

2) Since the film material can be selected, features such as low thermal expansion and low dielectric constant of the wiring board can be easily achieved.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing one embodiment of the present invention, Figure 2 (a)
3(b) are sectional views for explaining the process according to an embodiment of the present invention, and FIGS. 3(a) to 3(e) are sectional views showing the manufacturing process of the wiring board according to the present invention. Explanation of symbols 1 Polyimide film 2 Sputtered copper 3 Prepreg cured product 4 Through hole 5 Plating resist 6 Electroless copper plating layer ~ ((L) Fig. 2

Claims (2)

[Claims] 1. an insulating film (1), a uniform metal layer (2),
A wiring board material comprising an insulating resin base material (3). 2. A claim in which a metal layer (2) is formed on at least one side of the insulating film (1) by a resistance heating vapor deposition method, an electron beam vapor deposition method, an ion plating method, or a sputtering method, and is laminated and integrated with an insulating resin base material (3). Item 1. A method for producing a wiring board material according to item 1.