JP2003332751A - Multilayer circuit board and board therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multilayer circuit board and a board for multilayer circuit board which have high insulation reliability even if an insulation layer is thinned, enable high density of a wiring, and suppress an internal strain of the circuit board and the generation of a migration. <P>SOLUTION: A board for multilayer circuit board is composed of at least two layers of conductor metal layers 3, an insulating layer 1 laminated between the conductor metal layers 3, and a metal thin film layer 2 laminated on the surface of the insulating layer 1 side of the conductor metal layers 3. A multilayer circuit board 10 is formed by forming a lamination part S of the conductor metal layers 3 and the metal thin film layers 2, and a single layer T eliminating the conductor metal layers 3 on the metal thin film layers 2. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a resistor (Resi).
The present invention relates to a multilayer printed wiring board and a substrate for a multilayer printed wiring board having a built-in capacitor (stor) and a capacitor (Condenser). Particularly, even when the insulating layer is thinned, internal strain is suppressed and migration (greeding) is suppressed. For effective technology.

[0002]

2. Description of the Related Art In recent years, electronic devices, in particular, mobile terminal devices such as mobile phone terminals and mobile computers, have become smaller, thinner, higher in density and higher in performance, and will be used in various media such as the Internet in the future. Higher performance is required as an information terminal device that integrates communication and the like. On the other hand, in these electronic devices, memory, C
The performance of semiconductors such as PUs has been dramatically increased, and their performance has been dramatically improved. Along with this, there is a strong demand for higher densities of semiconductor packages for mounting semiconductor elements and printed wiring boards.

Therefore, in contrast to the conventional method in which a semiconductor package is mounted on a printed wiring board by mounting a semiconductor element on a lead frame and resin-sealed, a plastic package for mounting the semiconductor element directly on the printed wiring board and various modules. A new high-density surface-mounting type semiconductor package system such as a substrate and a BGA (ball grid array) has been proposed and is being adopted for electronic devices.

This printed wiring board for a semiconductor package has a higher density of wiring than conventional ones, and in particular, it is required to improve dimensional accuracy and heat resistance under heating when mounting a semiconductor element. There is. That is, there is a demand for finer and higher density in printed wiring boards for semiconductor packages, and recently, the formation and stacking of insulating layers and conductor layers on the inner layer circuit board and the connection between the conductor layers are performed layer by layer. The development of multi-layer printed wiring boards by the build-up method, which is carried out in Japan, has become popular.

In order to increase the density by this build-up method, it is necessary to reduce the diameter of via holes for establishing conduction between the conductor layers. In order to enable the formation of minute via holes, it is important to thin the insulating layer interposed between the conductor layers. Also, due to the faster CPU of the personal computer,
Similarly, it has become essential for memory modules to support higher signal speeds. In this way, when the signal becomes high-speed, the signal is reflected at the boundary and becomes noise, which deteriorates the quality of the transmitted signal. In order to prevent this, matching with an arbitrary impedance value is required, so the thickness and width of the conductor layer and the thickness of the insulating layer are designed. As the density increases in the future, that is, the width of the conductor layer decreases, it is required to thin the insulating layer in order to match the impedance value.

[0006]

As a multilayer printed wiring board by such a build-up method, a wiring board using a copper foil (conductor metal layer) to which a resin layer is attached has been known. However, when the resin layer, that is, the insulating layer is made thin, there is a problem that the insulation reliability between the conductor metal layers is lowered due to the influence of the rough surface shape of the copper foil. For example, when the insulating layer has a thickness of 20 μm, when hot pressing is performed with the rough surface side of the copper foil having a surface roughness Rz of 3.8 μm inside, the convex portion of the rough surface of the copper foil causes a gap between the two copper foils. Will short.

Further, in Japanese Patent Publication No. 5-500136, it is composed of two conductive sheets made of a conductive material and an insulating sheet made of a dielectric material laminated between the conductive sheets. A multilayer printed wiring board having a capacitor function has been proposed. In this case, in order to obtain a sufficient electric capacity, it is necessary to increase the dielectric constant of the dielectric material forming the insulating sheet or make the distance between the two conductive sheets sufficiently close.

However, if a method of dispersing a filler of a high-dielectric material in a resin material in order to increase the dielectric constant is adopted, it is unavoidable that conductive foreign matter is mixed in in the dispersing step. There is a problem that the insulation reliability between the conductive sheets may be reduced. Further, if the distance between the two conductive sheets is reduced, there is a problem that the conductive sheets are short-circuited as described above, and the yield in the production of the multilayer printed wiring board is extremely reduced.

Further, copper foil, which is a conductive material, is laminated on both sides of the insulating layer with a metal thin film layer such as a nickel layer interposed therebetween,
There has been proposed a multilayer printed wiring board in which a nickel layer is not dissolved and a copper foil is treated with an etching solution for etching to form a circuit pattern of the copper foil. In this substrate, the nickel layer remaining in a part of the circuit functions as a resistor.

However, if a voltage is continuously applied between the insulating layers, there is a problem that migration may occur depending on the film forming conditions of the nickel layer and environmental conditions, and insulation may occur between the two conductive layers. In particular, when the insulating layer is thinned to be used as a capacitor, migration is very likely to occur. Further, since the linear expansion coefficient of the nickel layer is lower than that of the copper foil, there is a problem that the internal strain tends to increase due to the difference in the linear expansion coefficient.

Therefore, the present invention has been made in view of the above circumstances. Even when the insulating layer is thin, the insulation reliability is high, the wiring density can be increased, and the inside of the printed wiring board can be made. An object of the present invention is to provide a multilayer printed wiring board and a substrate for a multilayer printed wiring board that can suppress distortion and suppress the occurrence of migration.

[0012]

As a result of intensive studies to solve the above problems, the inventors of the present invention have laminated a metal thin film layer made of nickel or the like between at least two conductor metal layers. By forming the insulating layer from the heat-resistant film excellent in mechanical strength and insulation and the adhesive resin layer, not only high insulation reliability and high wiring density but also internal strain can be prevented. The present invention has been completed by finding that the occurrence of migration can be suppressed in a small amount.

That is, the multilayer printed wiring board of the present invention is laminated on at least two conductor metal layers, an insulating layer laminated between the conductor metal layers, and an insulating layer side surface of the conductor metal layer. A multilayer printed wiring board in which a laminated portion of the conductor metal layer and the metal thin film layer and a single layer portion in which the conductor metal layer is removed from the metal thin film layer are formed on a substrate composed of a metal thin film layer. In the above, the insulating layer comprises a heat resistant film and an adhesive resin layer.

Here, the laminated structure of the heat-resistant film and the adhesive resin layer forming the insulating layer may be a structure in which the adhesive resin layers are formed on both surfaces of the heat-resistant film, or alternatively, both surfaces of the adhesive resin layer may be formed. It may have a structure in which a heat resistant film is formed. Further, in the multilayer printed wiring board of the present invention, the heat resistant film has a thickness of 17 μm or less, a glass transition temperature of 200 ° C. or more, and an elastic modulus of 2.
It is preferably made of a resin having GPa or more and strength of 200 MPa or more.

Further, the multilayer printed wiring board of the present invention is
The resin forming the heat resistant film is preferably an aromatic polyamide resin. Furthermore, the multilayer printed wiring board of the present invention has a linear expansion coefficient of the heat resistant film,
It is preferably 15 × 10 ⁻⁶ / ° C. Further, in the multilayer printed wiring board of the present invention, the thickness of the insulating layer is 20
It is preferably μm or less.

Further, the multilayer printed wiring board of the present invention is
The metal thin film layer can be applied even if it contains nickel. The substrate for a multilayer printed wiring board of the present invention comprises at least two conductor metal layers, an insulating layer laminated between the conductor metal layers, and a metal thin film layer laminated on the insulating layer side surface of the conductor metal layer. And a substrate for a multilayer printed wiring board, wherein the insulating layer comprises a heat resistant film and an adhesive resin layer.

In the multilayer printed wiring board substrate of the present invention, the heat resistant film has a thickness of 17 μm or less, a glass transition temperature of 200 ° C. or more, and an elastic modulus of 2.
It is preferably made of a resin having GPa or more and strength of 200 MPa or more. Further, in the substrate for a multilayer printed wiring board of the present invention, the resin constituting the heat resistant film is preferably an aromatic polyamide resin.

Further, in the multilayer printed wiring board substrate of the present invention, the heat-resistant film has a linear expansion coefficient of 15 × 10 5.
It is preferably ⁻⁶ / ° C. Further, in the multilayer printed wiring board substrate of the present invention, the insulating layer has a thickness of 20 μm.
The following is preferable. Further, the multilayer printed wiring board substrate of the present invention can be applied even if the metal thin film layer contains nickel.

According to the multilayer printed wiring board of the present invention, the insulating layer is formed thin by comprising the adhesive resin layer and the heat-resistant film excellent in mechanical strength and insulation as the insulating layer. Even so, since the insulation reliability can be ensured, it is possible to realize high density wiring. Further, even if a nickel layer having a smaller linear expansion coefficient than the conductor metal layer is used as the metal thin film layer, it is possible to suppress the internal strain and the occurrence of migration.

According to the substrate for a multilayer printed wiring board of the present invention, the multilayer printed wiring board of the present invention can be easily realized.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing a configuration example of the multilayer printed wiring board according to the present invention. The multilayer printed wiring board 10 according to the present embodiment includes a conductor metal layer 3 and a metal thin film layer for a multilayer printed wiring board substrate in which a metal thin film layer 2 and a conductor metal layer 3 are sequentially laminated on both surfaces of an insulating layer 1. 2 has a laminated portion S, and a single-layer portion T in which the conductor metal layer 3 is removed from the metal thin film layer 2 is formed.

That is, the multilayer printed wiring board 10 is
A laminated portion S of the conductor metal layer 3 and the metal thin film layer 2 constitutes a circuit, and a single layer portion T of the metal thin film layer 2 constitutes a resistor, and a capacitor (C) using this laminated portion S as an electrode.
And an RC built-in multilayer printed wiring board 10 provided with a resistor (R). The insulating layer 1 is composed of a heat resistant film 1a and adhesive resin layers 1b formed on both surfaces of the heat resistant film 1a. Here, the laminated structure of the heat resistant film 1a and the adhesive resin layer 1b is not limited to this, and the heat resistant film 1a may be adhered to both surfaces of the adhesive resin layer 1b.

Heat-resistant film 1a constituting the insulating layer 1
Has a glass transition temperature of 200 ° C. or higher and an elastic modulus of 2 GPa.
As described above, it is preferable to be made of a resin having a strength of 200 MPa or more. Here, if the elastic modulus and strength of the heat resistant film 1a are lower than the above-mentioned values, the heat resistant film 1a may be damaged by the projections of the conductor metal layer 3 and sufficient insulation may not be obtained.

If the glass transition temperature is less than 200 ° C., the heat resistance will be insufficient. Therefore, the conductor metal layer 3
The heat-resistant film 2b may be damaged by the projections (not shown) of the conductor metal layer 3 due to the high temperature during the press working performed when the layers are laminated, and sufficient insulation may not be obtained. In order to prevent the above problems from occurring, it is more preferable that the heat resistant film 1a is made of a resin that does not melt and decompose at a temperature lower than 350 ° C.

As such a high heat resistant resin material,
Aromatic polyamide resin (hereinafter referred to as aramid resin),
Aromatic polyimide resin (hereinafter referred to as polyimide resin), polyparabenzobisimidazole resin (PB
I), polyparabenzobisoxazole resin (PB
O), polyparabenzobisthiazole resin (PBT), and the like. Among these, aramid resin that satisfies the above required characteristics with a margin is particularly preferable.

Such an aramid resin is substantially composed of at least one of the repeating units of the following chemical formulas 1 and 2.

[0027]

[Chemical 1]

[0028]

[Chemical 2]

Here, Ar1, Ar2 and Ar3 are groups containing at least one aromatic ring and may be the same as or different from each other. Representative examples of such a group include those shown in Chemical Formula 3 below.

[0030]

[Chemical 3]

It is to be noted that some of the hydrogen atoms on the aromatic ring in Chemical formula 3 are substituted with a halogen group, a nitro group, an alkyl group, an alkoxy group or the like. Further, X is -O-, -CH
_{2 -, - SO 2 -,} - S -, - CO- , and the like. In particular, an aramid resin in which 80 mol% or more of all aromatic rings are bonded in the para position is particularly preferable in producing the multilayer printed wiring board 10 used in the present invention.

As long as the resin constituting the heat resistant film 1a does not impair the physical properties of the multilayer printed wiring board 10 or the object of the present invention, a lubricant, a coloring agent such as a dye or a pigment, a flame retardant, Antistatic agents, antioxidants, other additives, modifiers, other polymers and the like may be contained. The thermal expansion coefficient of the heat resistant film 1a is 0 to 15 × 1.
It is preferably 0 ^-6 / ° C. This coefficient of thermal expansion is 15 ×
When it is 10 ⁻⁶ / ° C. or more, when a semiconductor element is mounted on the multilayer printed wiring board 10 using the heat resistant film 1a, the dimensional change due to the thermal expansion of the substrate becomes large, and the bonding accuracy is lowered, or the bonding is performed. There is a possibility that problems such as cracks easily occur due to large thermal stress between the element and the substrate due to subsequent temperature change. In order to respond to finer wiring pitch, heat-resistant film 1
The coefficient of thermal expansion of a is more preferably 0 to 7 × 10 ^-6 / ° C.

The heat shrinkage rate of the heat resistant film 1a is 0.2% in order to improve the dimensional accuracy after mounting the semiconductor element.
The following is preferable, and 0.1% or less is more preferable. The characteristics of these heat resistant films 1a need to be satisfied in both the longitudinal direction and the width direction. These do not necessarily have to be the same depending on the circuit pattern of the multilayer printed wiring board 10, but a so-called balanced type heat-resistant film 1a whose characteristics in the longitudinal direction and the width direction are as close as possible is preferable.

The thickness of the heat-resistant film 1a is preferably thin because the capacity of the capacitor decreases in proportion to the reciprocal of the thickness, and is preferably 17 μm or less. Also, the thickness of the adhesive resin layer 1b is preferably thin for the same reason, but the uneven portion (projection) on the adhesive surface side of the metal thin film layer 2 or the metal conductor layer 3 is preferable.
Therefore, the heat-resistant film 1a may be damaged and the insulating property may be deteriorated. Therefore, the heat-resistant film 1a needs to be thicker than the uneven portion. And, the total of the heat-resistant film 1a and the adhesive resin layer 1b, that is, the thickness of the insulating layer 1 must be 20 μm or less to obtain a sufficient capacitor capacity.

Further, the manufacturing method of the heat resistant film 1a is not particularly limited, and a manufacturing method suitable for each resin may be adopted. For example, as for aramid resin, if it is soluble in an organic solvent, it is polymerized in a solvent, or once the polymer is isolated and then redissolved to form a solution, which is then subjected to a dry method or a wet method. Is formed into a film. On the other hand, those that are poorly soluble in organic solvents such as polyparaphenylene terephthalamide (hereinafter referred to as PPTA) are dissolved in concentrated sulfuric acid or the like to give a solution, and then a film is formed by a dry-wet method or a wet method.

In the wet method, the solution is extruded directly from a die into a coagulating liquid, or is cast on a metal drum or an endless belt as in the dry method and then introduced into the coagulating liquid to be solidified. Then, after washing the solvent, the inorganic salt, and the like remaining in the resin, treatments such as stretching, drying, and heat treatment are performed. Such heat-resistant film 1a may be subjected to surface treatment such as plasma treatment or corona treatment in order to improve the adhesiveness with the adhesive resin layer 1b. Considering the effect of improving the adhesive strength, durability of the adhesive strength, etc., plasma treatment is particularly preferable.

As the plasma treatment method, a continuous plasma treatment apparatus in which the heat resistant film 1a runs between the plasma discharge electrodes is preferably used. The pressure at this time is a pressure between vacuum and atmospheric pressure. Inert gas such as argon, xenon, neon, krypton, nitrogen, oxygen, hydrogen, hydrocarbon gas, ketones, alcohols, or a mixture of these is used as the atmosphere gas supplied to the discharge space during plasma processing. Further, in addition to the above-mentioned surface treatment, it is possible to use a chemical treatment with a silane coupling agent and a surface treatment such as physical roughening treatment such as sand blasting or wet blasting.

The adhesive resin layer 1b forming the insulating layer 1 is
For example, it is made of a resin such as an epoxy resin, a phenol resin, a polyimide resin, a fluororesin, or a polyphenylene ether. However, an epoxy resin is preferable from the standpoint of the balance of adhesiveness, heat resistance, cost, etc. Among these epoxy resins, an epoxy resin composition containing a curing agent is preferably used.

Examples of such epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin,
Biphenol type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin,
Bisphenol A novolac type epoxy resin, bisphenol F novolac type epoxy resin, phenol salicylaldehyde novolac type epoxy resin, cyclopentadiene type epoxy resin, alicyclic epoxy resin, aliphatic chain epoxy resin, glycidyl ester type epoxy resin,
Glycidyl ether compound of difunctional phenol, glycidyl ether compound of dihydric alcohol, glycidyl ether compound of polyphenol, hydantoin type epoxy resin, polyfunctional heterocyclic epoxy resin such as triglycidyl isocyanurate, and hydrogenated products thereof. Examples thereof include halides, and these can be used alone or in combination of two or more kinds.

As the epoxy resin curing agent, for example, amide type curing agents (dicyandiamide, aliphatic polyamine, etc.), aliphatic amine type curing agents (triethylamine, diethylamine, etc.), aromatic amine type curing agent (diaminodiphenylmethane, etc.) , Diaminodiphenyl sulfone, metaphenylenediamine, etc.), phenolic curing agent (phenol novolac resin, cresol novolac resin, etc.), imidazole curing agent (2-ethyl-4-methylimidazole, 2-phenylimidazole), acid anhydride type Examples of the curing agent include a curing agent (methylhexahydrophthalic anhydride) and the like, and these can be used alone or in combination of two or more kinds.

Furthermore, if a material having a high dielectric constant, such as barium titanate or barium niobate, is mixed with the adhesive resin layer 1b, when a capacitor is formed inside the multilayer printed wiring board, a capacitor having the same capacity is used. It can be formed in a smaller area. The high dielectric constant material to be mixed is dispersed in the resin as particles. At this time, however, there is a concern that if conductive foreign matter is mixed in, it will be sandwiched in the insulating layer 1 together with the high dielectric constant material, which will affect the insulation reliability. By forming the insulating layer 1 from the heat resistant film 1a and the adhesive resin layer 1b as in the present invention, the problem of insulation can be substantially avoided.

Further, in order to maintain the adhesive strength between the adhesive resin layer 1b and the heat resistant film 1a, for example, in the case of an epoxy resin composition, the molecular weight between the crosslinking points of the epoxy polymer and the crosslinking density are adjusted, It is preferable to use an epoxy composition having an improved toughness due to the softening of the skeleton, the formation of a sea-island structure by the introduction of the third component, and the addition of additives such as an elastomer component and a thermoplastic polymer. Good.

Examples of such an elastomer component include conjugated diene rubbers such as acrylonitrile butadiene rubber having both carboxyl groups and amino groups at both ends, butadiene rubber, acrylic rubber, nitrile rubber, chloroprene rubber, polyisobutene, and phenol-added polybutadiene compounds. Use of compounds and vinyl compounds such as poly (vinyl vinyl ether), ethylene vinyl ester hydrolysis copolymer, ethylene vinyl acetate copolymer, ethylene vinyl acetate maleic anhydride graft copolymer, vinyl chloride vinyl acetate maleic anhydride terpolymer, and polybutyl acrylate. You can

As the thermoplastic polymer, polyphenylene oxide, polyetherimide, polysulfone, polyethersulfone, polyarylate, polycarbonate, polyallylsulfone, polyhydantoin, polysiloxane and the like can be used. The glass transition temperature after curing of the adhesive resin layer 1b is about room temperature to 240 ° C., but when used for a high-density wiring board for surface mounting or the like, a heating process for mounting a semiconductor element is performed. In order to prevent the occurrence of thermal deformation in, the glass transition temperature after curing is preferably 150 ° C. or higher. In order to set the glass transition temperature after curing to 150 ° C. or higher, for example, when using an epoxy resin composition, use one having a high ratio of a polyfunctional component or a rigid component as an epoxy resin and a curing agent component. Therefore, a means such as increasing the crosslink density of the cured epoxy resin or increasing the rigidity of the molecular chain is usually used.

In addition to the above components, additives such as a curing catalyst, a flame retardant and a filler may be added to the adhesive resin layer 1b. As such a curing catalyst,
For example, imidazoles (2-methylimidazole, 2-
Ethyl-4-methylimidazole, 2-phenylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-ethylimidazole, 1-cyanoethyl-2
-Methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-methyl-2-ethylimidazole, 1-isobutyl-2-methylimidazole, etc., tertiary amines (1,8-diaza-bicyclo) [5.4.
0] Undecene, triethylenediamine, benzyldimethylamine, etc., organic phosphines (tributylphosphine, triphenylphosphine, etc.), tetraphenylboron salts (tetraphenylphosphonium tetraphenylborate, triphenylphosphinetetraphenylborate, etc.), quaternary ammonium Salts (tetraethylammonium bromide, tetraethylammonium chloride, tetrapropylammonium bromide, benzyltriethylammonium chloride, benzyltriethylammonium bromide, benzyltributylammonium chloride, benzyltributylammonium bromide or phenyltrimethylammonium chloride), boron trifluoride monomethylamine, etc. And these are simply Or it can be used in combination of two or more. The content of these curing catalysts is preferably 1 part by weight or less based on 100 parts by weight of the solid content of the epoxy resin composition.

Further, the thermal dimensional stability of the adhesive resin layer 1b,
In order to improve mechanical strength and adhesiveness, it is also preferable to add an inorganic or organic filler. Metal thin film layer 2
For example, a nickel layer containing nickel metal as a main component is preferably used. At this time, the nickel layer may partially contain a substance other than nickel metal, such as phosphorus or boron.

Further, the adhesive resin layer 1 constituting the insulating layer 1
The surface of the metal thin film layer 2 may be roughened in order to secure the adhesiveness with b. Here, any method may be used to form the metal thin film layer 2 made of nickel, but the most efficient method is electrolytic nickel plating using the conductor metal layer 3 as an electrode. When the metal thin film layer 2 made of nickel phosphorus or nickel boron is formed, electroless nickel phosphorus plating or electroless nickel boron plating may be performed after catalytic treatment on the upper surface of the conductor metal layer 3. Good.

The conductor metal layer 3 is made of, for example, copper foil or the like. The thickness of this copper foil is preferably 2 μm or more and 40 μm or less, and the surface roughness Rz of the copper foil is 0.
It is preferably 2 μm or more and 10 μm or less. The conductor metal layer 3 is formed on the upper surface of the metal thin film layer 2, and by the laminated portion S of the conductor metal layer 3 and the metal thin film layer 2,
The circuit is configured. This circuit is usually formed by pattern etching, but a necessary circuit may be formed by an additive method using plating.

Next, a method for manufacturing the multilayer printed wiring board in this embodiment will be described. FIG. 2 is a cross-sectional view showing one manufacturing process of the multilayer printed wiring board of the present invention. First, as shown in FIG. 2A, the multilayer printed wiring board 10 according to the present embodiment is formed by stacking conductor metal layers 3 on both surfaces of an insulating layer 1 with a metal thin film layer 2 interposed therebetween. The substrate 20 is formed.

Specifically, the insulating layer 1 is formed on both surfaces of the heat-resistant film 1a by applying a resin material as the adhesive resin layer 1b as a varnish dissolved in a solvent and drying it. The method for forming the insulating layer 1 is not limited to this, and for example, the adhesive resin layer 1b is applied and dried on one surface of the heat-resistant film 1a subjected to mold release, and then temporarily adhered to the heat-resistant film 1a while being heated and pressed. Therefore, the insulating layer 1 may be formed.

Then, on the insulating layer 1 in which the adhesive resin layers 1b are semi-cured on both surfaces of the heat resistant film 1a,
A metal foil in which a copper foil is bonded as the conductor metal layer 3 and a nickel layer is bonded as the metal thin film layer 2 is heated and pressed in a direction in which the metal thin film layer 2 side is bonded to the adhesive resin layer 1b, and metal is applied to both surfaces of the insulating layer 1. A substrate 20 for a multilayer printed wiring board on which a conductor metal layer 3 is formed via a thin film layer 2 is formed.

The method for forming the multilayer printed wiring board substrate 20 in which the conductor metal layer 3 is formed on both surfaces of the insulating layer 1 with the metal thin film layer 2 interposed therebetween is not limited to this.
The following method may be used. First, on one surface of the heat-resistant film, a metal thin film layer is formed to a required thickness by using a sputtering method or electroless plating method, and then a conductive metal layer is formed to a required thickness by using an electrolytic plating method. To plate. Then, on one surface, two heat-resistant films in which a metal thin film layer and a conductor metal layer are sequentially laminated, and the other surfaces on which the metal thin film layer and the conductor metal layer are not formed are bonded with an adhesive resin layer. Thus, it is possible to form a multilayer printed wiring board substrate having conductor metal layers formed on both surfaces of the insulating layer 1 with a metal thin film layer interposed therebetween. In this case, the insulating layer has a structure in which heat resistant films are laminated on both surfaces of the adhesive resin layer.

Then, a circuit pattern is formed on the upper surface of the conductor metal layer 3 so as to cover only the portions where the electrodes and the resistors are formed and the other portions are exposed by a standard process of dry film resist. Form. Then, both the conductor metal layer 3 and the metal thin film layer 2 can be etched, for example, by using an etching solution such as ferric chloride, as shown in FIG.
As shown in, the conductor metal layer 3 and the metal thin film layer 2 other than the electrodes and the resistor are not removed. After that, the dry film resist formed on the upper surface of the conductor metal layer 3 is peeled off using, for example, sodium hydroxide.

Then, a circuit pattern is formed on the upper surface of the conductor metal layer 3 so as to cover the portions where the electrodes are formed and expose the portions where the resistors are formed by a standard dry film resist process. Form. Then, the metal thin film layer 2 is not dissolved, and the conductor metal layer 3 can be etched. For example, an etching solution such as concentrated nitric acid is used to remove the conductor metal layer 3 in the portion to be the resistor as shown in FIG. The metal thin film layer 2 is exposed. Then, in the same process, the dry film resist formed on the upper surface of the conductor metal layer 3 is peeled off.

When the metal thin film layer 2 is a nickel-phosphorus alloy layer, first, only the electrode forming portion is covered and the other portion including the resistor forming portion is exposed on the upper surface of the conductor metal layer. A circuit pattern that provides such a state is formed by a standard process of dry film resist. And
The metal thin film layer 2 made of the nickel-phosphorus alloy layer is not dissolved, and the conductor metal layer 3 can be etched. For example, an ammonia-based etching solution is used to remove the conductor metal layer 3 other than the electrode formation site. Then, after peeling off the dry film resist as described above, a circuit pattern is formed on the dry film resist so as to cover the metal thin film layer 2 forming the resistor forming portion and expose the metal thin film layer 2 where the circuit is not formed. Form by standard process. Then, the conductor metal layer 3 is not dissolved, and the metal thin film layer 2 can be etched. Etching may be performed to form the metal thin film layer 2 only on the portion to be the resistor.

Thus, the two conductor metal layers 3, the insulating layer 1 laminated between the conductor metal layers 3, and the conductor metal layer 3
Of the conductive metal layer 3 to the multilayer printed wiring board substrate 20 including the metal thin film layer 2 laminated on the surface of the insulating layer 1 side of
It is possible to complete the multilayer printed wiring board 10 in which the laminated portion S of the metal thin film layer 2 and the single layer portion T in which the conductor metal layer 3 on the metal thin film layer 2 is removed are formed.

This multilayer printed wiring board 10 may be used in the state of FIG. 1, but if necessary, the insulating layer 1 and the metal are further provided on the uppermost surface of the multilayer printed wiring board 10 shown in FIG. The thin film layer 2 and the conductor metal layer 3 may be laminated as a buildup layer, and the respective conductor metal layers 3 may be electrically connected by through holes or via holes. At this time, a carbon dioxide laser,
An excimer laser, a YAG laser, etc. are used.

The method for manufacturing the multilayer printed wiring board 10 is not limited to this. For example, a build-up layer is formed without forming a circuit pattern on one side, and after the build-up layers are stacked, via hole drilling and panel plating are performed. After that, the circuit pattern may be formed by the above method. According to the multilayer printed wiring board 10 of the present embodiment, the insulating layer 1 is made thin by including the adhesive resin layer 1b and the heat-resistant film 1a excellent in mechanical strength and insulation as the insulating layer 1. Even if it is formed, the insulation reliability can be secured and the wiring can be made high in density.

Further, since the insulating layer 1 is configured to include the heat resistant film 1a having a small linear expansion coefficient, the difference in the linear expansion coefficient between the metal thin film layer 2 and the insulating layer 1 can be further reduced. It becomes possible to suppress internal distortion in the multilayer printed wiring board 10.

[0060]

EXAMPLES Next, the effects of the present invention will be verified based on the following examples. FIG. 3 is a sectional view corresponding to this embodiment of the multilayer printed wiring board according to the present invention. First, the core substrate of the multilayer printed wiring board 10A was formed.

Specifically, UL / made by Matsushita Electric Works, Ltd.
ANSI grade FR-4 Epoxy Multi R-17
A copper foil having a thickness of 18 μm is adhered to both sides of 66, and a double-sided board 4 having a thickness of only an insulating layer and having a thickness of 0.2 mm is drilled, and from one copper layer 4a surface to the other copper layer 4a surface. A through hole H is formed. The hole H serves as a through hole 5a that connects the conductor metal layers 3 insulated by the insulating layer 1 to each other. Then, after performing electroless plating, panel plating was performed to form a copper layer 4b of about 20 μm on the inner wall of the hole H.

Next, on one surface of the copper foil to be the conductor metal layer 3,
A nickel phosphorus layer which is the metal thin film layer 2 was formed. Specifically, a copper foil having a thickness of 18 μm (manufactured by Furukawa Electric Co., Ltd.,
The roughened surface of the copper foil type GTS) is
000) was used to polish and flatten with a belt polisher.
After removing the oxide layer with dilute sulfuric acid, a catalyst is applied with a pretreatment liquid for electroless nickel (Enipack CTS, manufactured by Ebara-Udylite Co., Ltd.), and further a pretreatment liquid for electroless nickel (Ebara-Udylite Co., Ltd.). (Manufactured by Anypack LV)
Was used to form a 0.4 μm thick nickel phosphorus layer on the polished surface.

Next, the adhesive resin layer 1b serving as an adhesive is adjusted, and the adhesive resin layer 1b is used as the heat resistant film 1a.
And the insulating layer 1 was formed. Specifically, first, 0.06 g of 2-ethyl 4-methylimidazole is added to 68.4 g of a low brominated epoxy resin (8011N80 manufactured by Asahi Kasei Epoxy Co., Ltd.) adjusted to an epoxy concentration of 81.4 wt% with a 2-butanone solvent. Then, 25 g of 2-butanone solvent and cresol novolac type epoxy resin (ECN1299 manufactured by Asahi Kasei Epoxy Co., Ltd.) 6.2
1 g was added to dissolve the solid content. And ABS
170 g of tetrahydrofuran (42.5 g of resin (acrylonitrile / butadiene ratio 30%, rubber content 35%))
What was melt | dissolved in was mixed with the epoxy resin prepared as mentioned above. Further, 1.86 g of dicyandiamide is dissolved in 17 g of methanol, put in a mixture of the epoxy resin and the ABS resin described above, and stirred so as to be uniform to form an epoxy resin composition containing an amide-based curing agent. Then, this epoxy resin composition was applied onto a PET film (thickness 25 μm) that had been subjected to a mold release treatment so as to have a thickness after drying of 10 μ by using a doctor blade, and air-dried at 80 ° C. An epoxy adhesive sheet is formed by drying with an air blow dryer.

This epoxy adhesive sheet (thickness 10 μm
m) was laminated on both sides of a polyamide film (Aramika, manufactured by Asahi Kasei Corporation, thickness: 4.5 μm) with a hot laminator at 100 ° C. Next, on one surface of the insulating layer 1,
The conductor metal layer 3 having the metal thin film layer 2 formed thereon was laminated so that the metal thin film layer 2 side was in contact with the insulating layer 1.

Specifically, of the epoxy adhesive sheet formed on the polyamide film, the PET film is peeled off only on one side, and the nickel layer side of the copper foil plated with the nickel layer on one side is also treated at 100 ° C. Laminated with hot laminator. Next, the insulating layer 1 in which the conductor metal layer 3 was laminated via the metal thin film layer 2 was laminated on both surfaces of the core substrate described above such that the conductor metal layer 3 was on the outside.

Specifically, an aramid film, in which a nickel layer and a copper foil were sequentially laminated, was applied to both surfaces of the core substrate so that the copper foil surfaces were on the outside, and heat and pressure molding was performed by a vacuum press. The vacuum press has a pressure of 0.5 MPa and a temperature of 120.
After 30 minutes under the condition of ℃, pressure 2.0MPa, temperature 1
It was carried out at 70 ° C. for 60 minutes. Next, a via hole 5b was formed in one of the conductor metal layers 3.

Specifically, a dry film resist was laminated on the copper foil surface, exposed with a mask and then developed to form a resist except for the hole portions where the via holes were formed. Subsequently, in order to etch the copper foil, it is treated with a ferric chloride solution, and in order to further etch the nickel layer, it is treated with a solution containing 200 g / L of copper sulfate and 3% of sulfuric acid, and a via hole is formed. The copper foil and the nickel layer were removed.

Then, after removing the dry film resist with sodium hydroxide, the copper foil and the nickel layer were removed with a carbon dioxide gas laser, and the hole of the copper foil was laser-processed in the portion where the insulating layer containing the aramid film was exposed. As a mask, a hole was drilled. Then, the hole is subjected to degreasing, desmearing, and catalyzing by using a normal through-hole forming process, and then electroless copper plating is performed to deposit about 0.2 μm of copper, followed by electrolytic Panel plating was performed with copper sulfate plating to form copper having a thickness of 20 μm on the inner wall of the hole.

Next, a circuit functioning as an electrode portion of a capacitor and a resistor was formed on the conductor metal layer 3 formed on the outermost surface of the core substrate. Specifically, a dry film resist is formed on the upper surface of the copper foil formed on the outermost surface of the core substrate so that the resist is left on the circuit portion, the capacitor electrode portion, and the resistor portion. And
The nickel-phosphorus layer did not dissolve, and the copper foil was etched with an ammonia-based alkaline etching solution that dissolves to remove the copper foil other than the circuit portion, the electrode portion of the capacitor, and the resistor portion.

Next, in the conductor metal layer 3 formed on the outermost surface of the core substrate, the planned resistor region is removed,
A resistor made of the metal thin film layer 2 was formed. In particular,
After removing the resist formed on the upper surface of the copper foil with sodium hydroxide, a pattern is again formed on the upper surface of the copper foil formed on the core substrate with a dry film resist so that the resist remains on portions other than the resistor portions. Then, the copper foil does not dissolve, but the nickel phosphorus layer dissolves.
Etching was performed by adding 3% of sulfuric acid to (g / l), and the nickel layer used as the resistor was left unetched. At this time, in the portion where the copper foil remains, the nickel phosphorus layer also remains on the lower surface of this copper foil. Then, the resist formed on the upper surface of the copper foil is peeled off as described above.

Through these steps, the capacitor (C) using the laminated portion S of the conductor metal layer 3 and the metal thin film layer 2 as an electrode, and the metal thin film layer 2 having no circuit formed on the upper surface thereof.
The RC built-in multi-layer printed wiring board 10A having a resistor (R) consisting of a single layer portion was completed. Here, in the RC built-in multilayer printed wiring board 10A having the above-described configuration, the circuit portion is formed by the laminated portion S of the metal thin film layer 2 made of the nickel phosphorus layer and the conductor metal layer 3 made of the copper foil. Due to the high resistance of the phosphorus layer, it was possible to obtain the same conductivity as the circuit with only copper foil, where the resistance of the circuit portion is determined by the copper foil.

Further, the capacitor is composed of the copper foil 4a of the core layer.
Electrodes are formed on both surfaces of the metal thin film layer 2 and the conductor metal layer 3 by the laminated portion S via the adhesive resin layer 1b, the heat resistant film 1a, and the adhesive resin layer 1b. Since 1 was only 24.5 μm, a sufficient electrostatic capacity could be secured. Further, the resistor is composed of a single layer portion T of the metal thin film layer 2 made of a nickel phosphorus layer,
Since the insulating layer 1 is formed very thin over the entire surface, it is easy to form a via hole and it is possible to reduce the diameter.

Furthermore, due to the strength and barrier properties of the heat-resistant film 1a, short-circuit did not occur even if the insulating layer 1 was thin, and migration resistance between layers was good. Further, in the insulating layer 1 including the heat resistant film 1a and the adhesive resin layer 1b, the coefficient of linear expansion of the adhesive resin layer 1b is 100 × 1.
Although it is close to 0 ^-6 / ° C, the heat-resistant film 1a having a small linear expansion coefficient between the adhesive resin layers 1b (2 x 10
^Since the linear expansion coefficient of ⁻⁶ / ° C. and the elastic modulus of 15 GPa) are inserted, the linear expansion coefficient of the entire insulating layer 1 is 10 × 10 ⁻⁶ /
It was ℃. From this, even if the metal thin film layer 2 made of a nickel layer having a small linear expansion coefficient and the insulating layer 1 were adhered to each other, the internal strain due to the difference in the linear expansion coefficient could be suppressed.

[0074]

As described above, according to the multilayer printed wiring board of the present invention, the insulating layer is composed of the heat resistant film and the adhesive resin layer, so that even if the insulating layer is thin, the insulation reliability is improved. In addition, it is possible to increase the density of wiring, and it is possible to suppress the occurrence of internal strain and migration. According to the substrate for a multilayer printed wiring board of the present invention, the multilayer printed wiring board of the present invention can be easily realized.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration example of a multilayer printed wiring board according to the present invention.

FIG. 2 is a cross-sectional view showing one manufacturing process of a multilayer printed wiring board according to the present invention.

FIG. 3 is a cross-sectional view showing a configuration example corresponding to an example of a multilayer printed wiring board according to the present invention.

[Explanation of symbols]

1 insulating layer 1a Heat resistant film 1b Adhesive resin layer 2 Metal thin film layer 3 Conductor metal layer 4 double-sided board 5a through hole 5b beer hall 10, 10A Multilayer printed wiring board 20 Multilayer printed wiring board

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Mitsuhiro Watanabe             Kanagawa Prefecture Yokosuka City River 1-17-1 Share             Inside the ceremony company Multi F-term (reference) 5E346 AA12 AA13 AA14 AA15 AA36                       AA37 AA39 CC02 CC08 CC21                       CC25 CC32 CC37 CC55 CC58                       DD12 DD32 DD48 EE06 EE09                       EE18 EE34 FF45 GG15 GG22                       GG28 HH06 HH08 HH11 HH24                       HH25 HH26

Claims (12)

[Claims] 1. A substrate comprising at least two conductor metal layers, an insulating layer laminated between the conductor metal layers, and a metal thin film layer laminated on a surface of the conductor metal layer on the side of the insulating layer. A multilayer printed wiring board having a laminated portion of the conductor metal layer and the metal thin film layer, and a single layer portion in which the conductor metal layer is removed from the metal thin film layer, wherein the insulating layer is heat resistant. A multilayer printed wiring board comprising a film and an adhesive resin layer. 2. The heat resistant film has a thickness of 17 μm.
And a glass transition temperature of 200 ° C. or higher,
The multilayer printed wiring board according to claim 1, which is made of a resin having an elastic modulus of 2 GPa or more and a strength of 200 MPa or more. 3. The multilayer printed wiring board according to claim 2, wherein the resin is an aromatic polyamide resin. 4. The heat-resistant film has a linear expansion coefficient of 1.
5. It is 5 * 10 < ^-6 > / [deg.] C., and it is characterized in that
The multilayer printed wiring board according to any one of 1. 5. The multilayer printed wiring board according to claim 1, wherein the insulating layer has a thickness of 20 μm or less. 6. The multilayer printed wiring board according to claim 1, wherein the metal thin film layer contains nickel. 7. A multilayer printed wiring comprising at least two conductor metal layers, an insulating layer laminated between the conductor metal layers, and a metal thin film layer laminated on the surface of the conductor metal layer on the side of the insulating layer. It is a board for boards, Comprising: The said insulating layer consists of a heat resistant film and an adhesive resin layer, The board | substrate for multilayer printed wiring boards characterized by the above-mentioned. 8. The heat resistant film has a thickness of 17 μm.
And a glass transition temperature of 200 ° C. or higher,
The substrate for a multilayer printed wiring board according to claim 7, which is made of a resin having an elastic modulus of 2 GPa or more and a strength of 200 MPa or more. 9. The substrate for a multilayer printed wiring board according to claim 8, wherein the resin is an aromatic polyamide resin. 10. The substrate for a multilayer printed wiring board according to claim 7, wherein the heat resistant film has a coefficient of linear expansion of 15 × 10 ⁻⁶ / ° C. 11. The substrate for a multilayer printed wiring board according to claim 7, wherein the insulating layer has a thickness of 20 μm or less. 12. The multilayer printed wiring board substrate according to claim 7, wherein the metal thin film layer contains nickel.