JP2000022332A - Manufacture of multilayer printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure high adhesion of a conductor layer, resistance to shock, resistance to heat, etc., by forming a conductor layer in an inner layer panel by building-up using an additive method, and performing a subtractive method using a copper clad insulating sheet only in the case that conductor of the outermost layer is formed. SOLUTION: The surface of a conductor pattern 1 of an inner layer panel composed of a glass epoxy laminate 2 is roughened and a barrier layer is formed. An insulating sheet is laminated, a polyethylene terephthalate film is peeled after cooling, and a first resin layer 3 is formed on the conductor pattern 1. A BVH(blind via hole) is formed on the resin layer 3, and the surface of the first resin layer 3 is roughened. Thereon a plating BVH is formed, and an inner layer multilayer panel is obtained. By a subtractive method, a copper clad insulating sheet 12 is laminated on the inner layer multilayer panel, and a second resin layer 11 and a copper foil 10 are formed on a plating copper circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer printed wiring board, and more particularly to a multilayer printed wiring board which is excellent in reliability such as heat resistance, electric insulation, adhesiveness of outer layer conductor, water resistance, flame retardancy and impact resistance, and has a high reliability. The present invention relates to a method for manufacturing a multilayer printed wiring board excellent in density.

[0002]

2. Description of the Related Art As electronic devices have become smaller and more multifunctional,
Currently, printed wiring boards are moving toward higher densities. For example, the diameter of a through hole including an interstitial via hole such as a thinner conductor circuit, a higher multilayer structure, a through via hole, a blind via hole (hereinafter referred to as "BVH"), and a buried via hole. In addition, there are high-density mounting by surface mounting of small chip components, and various methods for manufacturing a multilayer printed wiring board excellent in mass productivity are being developed. In addition, multi-chip modules (MCM) and ball grid arrays (BGA) with multiple bare chips and chip size packages (CSP) are also formed with the above-mentioned via holes, but are superior in mass productivity from the conventional device base and ceramic base. An MCM based on a resin substrate is desired.

Conventionally, a wiring pattern of an inner panel is formed by performing an etching process on both surfaces of a copper-clad laminate in which copper foil is laminated on both surfaces via one or more glass epoxy prepregs or glass polyimide prepregs, and a blackening process is performed. After laying, prepreg and copper foil are laid up appropriately and laminated by heating and pressing with a press, followed by drilling, plating,
2. Description of the Related Art A multilayer printed wiring board has been manufactured by performing a pattern such as etching. However, in the conventional method, since a prepreg containing glass cloth is used as an interlayer insulating material, the weight is large, the thickness is restricted, and it has been difficult to reduce the thickness and weight required of an electronic device having a higher density. Further, although a material having a low dielectric constant required for high-speed operation is required, there is a limit in using a conventional prepreg containing glass cloth having a high dielectric constant.

In the conventional method of manufacturing a multilayer printed wiring board, since a hot press is generally used as described above, the inner layer panel and the prepreg 1 are prepared in preparation for the hot press.
It is necessary to lay-up two or more sheets, a copper foil, a release film, a mirror press plate, etc., heat-press them with a hot press or a vacuum hot press, and then take out and disassemble. In addition, there is a problem that batch production such as lay-up, temperature rise at the time of heating, heat press bonding, cooling, dismantling, etc. is required, resulting in a large number of steps.

[0005] Further, in the case of drilling holes, the number of steps is increased in order to drill one hole at a time, so that a plurality of copper-clad laminates are generally stacked to increase the efficiency of drilling. However, as the density has increased recently, and small-diameter holes such as through via holes and BVHs are required, it is not possible to perform drilling by stacking copper-clad laminates due to problems such as processing accuracy and drill strength. It becomes possible, and advanced processing technology is required for drilling holes one by one with high accuracy, and there has been a problem such as a decrease in productivity.

Further, laser processing using an excimer laser, a carbon dioxide laser, a YAG laser or the like instead of drilling has been studied and is being put to practical use. The carbon dioxide laser has a high processing speed but has a problem that the residue remaining on the bottom of the BVH is easily carbonized and needs to be removed, and cannot be easily removed by the conventional desmear treatment. Excimer lasers have high processing accuracy and hardly leave BVH residues, but have a low processing speed and have a problem in productivity. YAG lasers currently have difficulties in processing shapes. In any case, since the laser processing needs to be performed by concentrating the beam, it is necessary to perform the scanning, and it is difficult to perform both sides simultaneously, which limits the productivity.

To solve the above problem, Japanese Patent Laid-Open Publication No. 2-98
995, JP-A-2-18892, JP-A-5-299837 and JP-A-6-148877.
Publications have been proposed. These are techniques for forming a BVH by forming a photosensitive resin composition to which heat-resistant fine particles and a rubber component that can be dissolved and removed are added on an inner layer panel, exposing to ultraviolet rays, and developing with an organic solvent. Further, this is a technique in which the surface of the resin composition is treated with an oxidizing agent to dissolve the heat-resistant fine particles and the rubber component to form an anchor shape, thereby ensuring the adhesion of plated copper. However, there is a problem that the working environment is poor because an organic solvent is used at the time of development, and development with an alkaline aqueous solution has been desired.

Further, in Example 1 of JP-A-8-139457, phthalic acid-modified novolak type epoxy acrylate and crosslinked carboxylic acid-modified acrylonitrile-butadiene rubber XER-91 (trade name, manufactured by Nippon Synthetic Rubber Co., Ltd.) UV exposure using a resin composition consisting of a photoinitiator and a filler, and BVH
Is disclosed. Although development with an aqueous alkali solution is possible with the above composition, XER-91 is rubber fine particles having an average particle diameter of 70 nm, and the depth and roughness of an anchor obtained by dissolving and removing rubber fine particles with an oxidizing agent are insufficient. However, there was a drawback that sufficient peel strength with the plated metal could not be obtained.

In order to increase the peeling strength of the plating metal by the so-called additive method disclosed in the above publication, a method of increasing the anchor on the resin surface to 5 μm or more can be adopted. The thickness of the insulating layer between the inner conductors may be insufficient, causing a problem of poor insulation. Also, when the anchor is deep, it is necessary to extend the time until the metal foot completely dissolves in the anchor when forming the conductor pattern by etching as in the semi-additive method, which causes variations in the conductor width and it is difficult to form a fine pattern. Disadvantageous. Therefore, it is preferable that the anchor is as shallow as possible, but there is a problem that the peeling strength is low.

[0010]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems and secures high adhesion, impact resistance and heat resistance, flame retardancy, electrical insulation reliability, and the like of a conductive layer. An object of the present invention is to provide a method for manufacturing a multilayer printed wiring board having excellent workability such as fine BVH using an aqueous solution.

[0011]

According to the present invention, in order to solve the above-mentioned problems, first, an additive method is used to build up a conductor in an inner layer panel and form a conductor. This is performed by a subtractive method using an insulating sheet. Specifically, (1) After roughening the surface of the conductor pattern of the inner layer plate having the conductor pattern, the first resin layer having an active energy ray-curing property and an insulating property and heat resistance after curing is formed on the inner layer board. (2) irradiating a predetermined position of the first resin layer with an active energy ray to cure an irradiated portion, and then dissolving the unirradiated portion of the resin layer to provide a BVH; 3) a step of roughening the surface of the first resin layer after curing; (4) a step of forming a metal layer on the surface of the resin layer and the BVH by plating;
(5) a step of forming a conductor pattern on the surface; (6) a step of forming a multilayer panel by repeatedly stacking the above steps (1) to (5) if desired; (7) roughening the surface of the conductor pattern Step; (8) a copper-clad insulating sheet in which a second resin layer having electron beam curability and / or heat curability and having insulation and heat resistance after curing is previously applied to a roughened surface of a copper foil, Laminating the panel or the multilayer panel; (9)
A step of dissolving the copper foil of the BVH portion and a second resin layer thereunder; (10) a step of curing the second resin layer; (11) a step of forming a metal layer by plating; and (12) a conductor on the surface. Forming a pattern. A method for manufacturing a multilayer printed wiring board, comprising:

In other words, the outermost conductor needs to have a sufficient adhesive strength to solder electronic components or connect them with a conductive material. Also, a high adhesive strength is required when repairing electronic components. In the present invention, a copper-clad insulating sheet in which a resin is applied to a roughened surface of a copper foil having a large and stable peeling strength is used as the outermost layer. Even if the conductor formed between the inner layer panel and the outer layer is formed by the additive method, the conductor is embedded in the resin, so that there is no problem even if the peel strength is low. The anchor on the surface of the insulating layer formed by the additive method is preferably 5 μm or less, more preferably 1 to 3 μm.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, the first resin layer has alkali solubility and ultraviolet curability, and the second resin layer has alkali solubility and electron beam and / or thermosetting properties. It is preferable to use a material having Both the first resin layer and the second resin layer are treated with an alkaline solution in BVH.
Can be formed, so that the manufacturing environment is good.

The first resin layer includes an acrylic and / or methacrylic (hereinafter referred to as "(meth) acrylic") polymer having a carboxyl group (hereinafter referred to as a "first component") and a carboxyl. Crosslinked rubber-like fine particles having a group (hereinafter, referred to as “second component”), benzoguanamine-based resin fine particles (hereinafter, referred to as “third component”) as a fine particle substance soluble after curing of the resin composition, active energy, and And / or a thermal crosslinking agent (hereinafter, referred to as “fourth component”), an ultraviolet polymerization initiator (hereinafter, referred to as “fifth component”), and a sensitizer for ultraviolet polymerization (hereinafter, referred to as “sixth component”). ), A thermosetting agent (hereinafter, referred to as “seventh component”), and a flame retardant (hereinafter, referred to as “eighth component”) mixed therein (hereinafter, referred to as “resin composition of the present invention”). ) Utilizing, as a second resin layer, a first component, a second component, the third component, the fourth component, the seventh
The use of a resin composition containing the component and the eighth component (hereinafter referred to as “the second resin composition of the present invention”) preferably produces the multilayer printed wiring board of the present invention.

The first resin composition and the second resin composition of the present invention (hereinafter referred to as “the resin composition of the present invention”
Called. ) Is mainly composed of a combination of a (meth) acrylic polymer having a carboxyl group and crosslinked rubber-like fine particles having a carboxyl group.
There are advantages that H processing can be easily dissolved in an alkaline aqueous solution, and that the resin after curing is stable against thermal shock such as soldering of a resin.

With a combination of (meth) acrylic polymer having a carboxyl group and crosslinked rubber-like fine particles having no carboxyl group, it is difficult to process the BVH of the fine hole. It has been found that crosslinked rubber fine particles having the following are excellent in alkali solubility. It is considered that the crosslinked rubber fine particles are dispersed in the resin composition in a sea-island state in the resin composition, and that the fine particles have a carboxyl group on the surface thereof so that they are easily dissolved in an alkaline aqueous solution. Uncrosslinked rubber fine particles having a carboxyl group are completely mixed with other components such as a (meth) acrylic polymer and a crosslinking agent, so that they do not form a sea-island shape and cracks are easily generated. Since the rubber fine particles having a carboxyl group as in the present invention become sea-island-like with other components such as a (meth) acrylic polymer and a cross-linking agent, an impact at normal temperature and a stress at the time of heating are applied, and the rubber fine particles are present. By doing so, it is thought that even if partial destruction of the resin occurs, it stops at the interface between the rubber fine particles, so that the destruction does not extend and cracks do not occur.

The basic skeleton of the first component used in the present invention is:
Linear polymer containing acrylic acid and / or methacrylic acid (hereinafter referred to as "(meth) acrylic acid") and (meth) acrylic acid ester as main components (hereinafter referred to as "unreacted acrylic polymer"). As a main component. Unreacted acrylic polymer is methyl (meth) acrylate,
Ethyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth)
Acrylate, (meth) acrylic acid ester such as tetrahydrofurfuryl (meth) acrylate and acrylic acid are dissolved at an appropriate composition ratio in an alcohol solvent such as isopropyl alcohol, ethylene glycol monoethyl ether, propylene glycol monomethyl ether,
It is obtained by copolymerization using azobisisobutyronitrile, benzoyl peroxide or the like as an initiator. As the first component, glycidyl group and C ＝ C
A compound having an unsaturated double bond is added.

Unreacted acrylic polymers include (meth)
As the third component other than acrylic acid and the (meth) acrylic acid ester, a vinyl compound such as styrene or acrylonitrile can be copolymerized. In particular, when heat resistance and water resistance are required, styrene is used as the total monomer amount. 5 for
It is preferable to copolymerize in the range of 30% by weight.

The ratio of (meth) acrylic acid to other components in the unreacted acrylic polymer may be set such that the acid value of the final composition is 0.5 to 0.5 when the resin before curing needs alkali solubility. It is necessary to adjust to a range of 3.0 meq / g, and as described later, considering that part of the acid is used for addition of a compound having a glycidyl group and a C ＝ C unsaturated double bond, Before the reaction with the compound, the content of (meth) acrylic acid is preferably 20 to 50% by weight based on all monomers.

If the resin composition before curing does not require alkali solubility, there is no need to consider the acid value, so if the polymerization is carried out so that the amount of (meth) acrylic acid is at least equivalent to the glycidyl compound. Good.

Next, a compound having a glycidyl group and a C ＝ C unsaturated double bond to be added to (meth) acrylic acid copolymerized in an unreacted acrylic polymer chain will be described.

This addition reaction causes the (meth) acrylic polymer to become insoluble and infusible by heating or an energy beam such as an electron beam or an ultraviolet ray capable of polymerizing a C ＝ C double bond, and is sufficient for a wiring substrate. The compound having a glycidyl group and a C ＝ C unsaturated double bond is used for imparting mechanical properties. Examples of the compound having a glycidyl group and a CＣC unsaturated double bond include glycidyl (meth) acrylate, allyl glycidyl ether, vinylbenzyl glycidyl ether, and 4-glycidyloxy-3. , 5-
Glycidyl (meth) acrylate is preferred among these because dimethylbenzyl acrylamide and the like can be mentioned. Among these, glycidyl (meth) acrylate is preferable in that it is easily available and can easily be added to an acid.

As described in JP-A-7-233226 filed by the present inventors, (meta)
Another glycidyl compound such as brominated phenylglycidyl ether may be added to a part of the carboxylic acid in the acrylic polymer.

The crosslinked rubber-like fine particles containing a carboxyl group, which is the second component, form a structure corresponding to an island having a sea-island structure by curing the resin composition of the present invention and then uniformly dispersing it in the cured product. And cross-linked acrylic rubber having a carboxyl group, cross-linked NBR, cross-linked MBS, and the like. In addition, in order to obtain sufficient impact resistance, it is preferable to add the resin composition of the present invention in the range of 5 to 40% by weight based on the whole. 40
When used in an amount of more than 10% by weight, there is no problem in terms of impact resistance. However, when a resin varnish in which the resin composition of the present invention is mixed in a solvent is produced, the second component is easily separated and the varnish is stable. Is unfavorably increased, and coating unevenness and air bubbles are apt to occur when coating and drying the copper foil. Further, when the crosslinked rubber-like fine particles used in the present invention are completely dissolved in the resin, it is difficult to stably reproduce the sea-island structure when the resin is cured, and the rubber-like component has a sea-island structure in the sea portion. Glass transition temperature (Tg) of the cured product
From the viewpoint of lowering the physical properties at high temperatures. For this reason, it is preferable that the particulate polymer is hardly soluble in a solvent.

Further, since the second component contains a carboxyl group, the solubility when the uncured resin composition of the present invention is dissolved and removed with an alkaline aqueous solution or the like is remarkably improved. No.1 even when carboxyl group is not contained
Although the resin layer can be removed by the carboxyl group contained in the component, the resin layer cannot be dissolved uniformly, and the swollen resin is removed by the spraying force of an alkali developing machine so as to be removed. For this reason, when BVH is formed by alkali development, if rubber-like fine particles containing no carboxyl group are used in place of the second component, the yield of drilling is reduced, and a fine blind having a hole diameter of 0.5 mm or less is used. In the via hole, a layer in which the flexible fine particles remaining at the bottom of the hole are fused to each other is formed, and the hole is not formed. On the other hand, since the second component used in the present composition has improved solubility in an alkali developing solution, it can be processed with a high yield even with such a fine hole diameter.

When the rubber-like fine particles having a carboxyl group as the second component are dispersed in the resin composition of the present invention, the second component and other components are previously mixed in a solvent such as methyl ethyl ketone, and then the mixture is mixed with a homomixer. It is necessary to disperse and to loosen the secondary aggregation of the fine particles. Further, as another method, a three-roll, ball mill or the like is also suitable. If used without sufficiently agglomerated secondary agglomeration, the second component is separated in the resin varnish, and the storage stability of the varnish is significantly reduced, and even if this varnish is coated on a copper foil, a uniform coating film can be obtained. Therefore, when laminating a copper-clad sheet coated with the resin composition of the present invention on an inner layer panel having an inner circuit, air bubbles are likely to bite, and the interface between the air bubbles and agglomerated particles and other resin components is insulated. Reduce the nature.
Further, when the aggregated particles are large, the copper foil is deformed while the coated copper-clad sheet is stacked or wound and stored, so that formation of a fine circuit by the etching method is significantly impaired.

The third component, a fine particle substance which can be dissolved after curing the resin composition, has heat resistance, solvent resistance and insulating properties, and needs to be soluble in a roughening liquid. The present inventors have conducted intensive research and have found that a resin composition using benzguanamine-based resin fine particles can be used to form a conductor layer having a high adhesive force by specifically setting roughening treatment conditions and resin surface treatment conditions. I found that it is possible. As the benzoguanamine-based resin, a benzoguanamine / formaldehyde condensate, a benzoguanamine / melamine / formaldehyde condensate, or the like can be used. The average particle diameter of these fine particles is preferably 1 to 10 μm, more preferably 1 to 5 μm
It is. If the thickness is less than 1 μm, sufficient adhesion to the plated copper cannot be obtained, and if the particle size exceeds 10 μm, the surface roughness becomes too large, and a copper residue is easily generated when unnecessary plated copper is removed by etching, thereby forming a fine pattern. Becomes difficult, which is not preferable. The amount is 5 to 100 parts by weight, preferably 10 to 40 parts by weight, based on the resin component.

An inorganic filler such as calcium carbonate having an average particle size of several μm and soluble in an acid, an oxidizing agent, or the like may be used in combination with the above resin fine particles as the soluble fine particle substance of the third component.

If NBR containing a carboxyl group having a small average particle diameter is used as the rubber fine particles containing a carboxyl group of the second component, a third particle having a relatively large average particle diameter can be obtained.
The synergistic effect with the dissolvable fine particles of the component increases the adhesive strength of the plated copper. In addition, the present inventors have found that when an acrylic rubber containing a carboxyl group is used as the second component, the insulation resistance after moisture absorption is high due to a combination with the acrylic polymer containing a carboxyl group of the first component.

Next, a polymerizable compound having at least one terminal C ＝ C unsaturated double bond can be used as a crosslinking agent as the fourth component. These are compounds having an acryloyl and / or methacryloyl (hereinafter referred to as “(meth) acryloyl”) group, an allyl group, a vinyl group, or the like at the terminal. Specifically, methyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate having one double bond, 2
Monofunctional (meth) acrylates such as -hydroxy-3-phenoxypropyl acrylate; compounds having a vinyl group such as styrene and acrylonitrile; compounds having an allyl group such as allylphenol and eugenol; N-phenylmaleimide; Compounds having a maleimide group such as -N-phenylmaleimide and p-chloro-N-phenylmaleimide, and the like having two double bonds include 1,3-butanediol di (meth) acrylate and diethylene glycol di ( Di (meth) acrylates such as (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, di (meth) acrylate of bisphenol A type epoxy, and urethane acrylate; Rui divinylbenzene and vinyl compounds, or diallyl phthalate, and diallyl ether and allyl compounds such as bisphenol A. When the number of double bonds is three or more, trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate, phenol novolak epoxy acrylate, triallyl isocyanurate and the like can be mentioned.

Among the above polymerizable compounds, a compound having a long cross-linking point and providing a soft cured product, such as polypropylene glycol di (meth) acrylate,
In terms of compatibility with the components, urethane (meth) acrylate, polyethylene glycol di (meth) acrylate,
Trimethylolpropane tri (meth) acrylate or pentaerythritol tri (meth) acrylate is preferred. The compounding amounts of these compounds are as follows:
The range of 10 to 100 parts by weight relative to 00 parts by weight is preferable from the viewpoint of heat resistance.

As the UV polymerization initiator of the fifth component, benzyl, benzoin, benzoin alkyl ether, 1-hydroxycyclohexyl phenyl ketone as a benzoin ether type; benzyl dialkyl ketal as a ketal type; 2,2′-dialico as an acetophenone type Xyacetophenone, 2-hydroxyacetophenone, pt-butyltrichloroacetophenone, pt
-Butyldichloroacetophenone; benzophenone-based benzophenone, 4-chlorobenzophenone,
4'-dichlorobenzophenone, 4,4'-bisdimethylaminobenzophenone, methyl o-benzoylbenzoate, 3,3'-dimethyl-4-methoxybenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, dibenzosuberone Thioxanthone, 2-chlorothioxanthone, 2-alkylthioxanthone, 2,4-dialkylthioxanthone, 2-alkylanthraquinone,
2,2′-dichloro-4-phenoxyacetone and the like are included, and the compounding amount is preferably 0.5 to 10 parts by weight based on 100 parts by weight of the resin composition of the present invention. If the amount is less than 0.5 part by weight, the reaction does not sufficiently start, and if the amount exceeds 10 parts by weight, the resin layer becomes brittle.

As the sensitizer for ultraviolet polymerization as the sixth component, Nissocure EPA, EM manufactured by Shin Nisso Chemicals, Inc.
A, IAMA, EHMA, MABP, EABP, etc., Kayacure EPA, DETX, DMBI manufactured by Nippon Kayaku Co., Ltd.
Quanta, manufactured by Ward Blenkinsop
cure EPD, BEA, EOB, DMB, etc., DABA manufactured by Osaka Organic Co., Ltd., PAA, D manufactured by Daito Chemical Co., Ltd.
AA and the like. The compounding amount is preferably 0.5 to 10 parts by weight based on 100 parts by weight of the resin composition of the present invention.
When the amount is less than 0.5 part by weight, the reaction rate of the active energy ray curing does not improve. When the amount exceeds 10 parts by weight, the reaction speeds up and the shelf life is reduced.

The thermosetting agent, which is the seventh component, includes an organic peroxide type and an azobis type. In order to obtain storage stability, a high decomposition initiation temperature is required. Dialkyl peroxide is most suitable in terms of low generation, and dicumyl peroxide, t-butylcumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethylperoxide Dimethyl-2,5-di (t-butylperoxy) hexyne and the like. In addition, the amount of addition is determined according to the resin composition 1 of the present invention.
0.5 to 5 parts by weight, preferably 0.5 to 5 parts by weight, per 100 parts by weight.
If the amount is less than 5 parts by weight, the polymerization is insufficient. If the amount exceeds 5 parts by weight, the shelf life is shortened and the amount of the decomposition product of the curing agent is increased, so that the heat resistance is impaired.

The flame retardant as the eighth component includes a reaction product of a glycidyl ether of a halogenated phenol compound and (meth) acrylic acid. Specific examples thereof include a reaction product of tetrabromobisphenol A diglycidyl ether and methacrylic acid, a reaction product of tetrabromobisphenol A diglycidyl ether and acrylic acid, and an epoxy containing both a tetrabromobisphenol A skeleton and bisphenol A containing no bromine. Resin (for example, Dow D
A reaction product of (ER514) and (meth) acrylic acid can be used, and if desired, two or more kinds can be added.
Bisphenol A such as a monobromo compound or a dibromo compound contained as a by-product of tetrabromobisphenol A
Substances having different numbers of bromine substitutions per skeleton may be present. Further, a reaction product of a monofunctional brominated epoxy resin (for example, BROC manufactured by Nippon Kayaku Co., Ltd.) and (meth) acrylic acid or a polyfunctional brominated epoxy resin (for example, BREN manufactured by Nippon Kayaku Co., Ltd.) Reactants of (meth) acrylic acid can also be used. Among them, a bifunctional compound that can have both strength and appropriate flexibility when used in the present resin composition is preferable, and bromine is particularly preferable as a halogen type because of its excellent flame retardancy. If desired, two or more of these compounds can be added. The eighth component is preferably blended so that the bromine content in the resin composition is from 5% by weight to 25% by weight.

If the bromine content is less than 5% by weight, the flame retardancy of the cured resin cannot be obtained unless phosphorus is added in an amount of 2% by weight or more. In this case, however, the insulating property is deteriorated. When the content is 25% by weight or more, flame retardancy can be obtained, but the halogen compound is easily desorbed during heating, so that the solder heat resistance and long-term reliability are undesirably reduced. For this purpose, the following phosphate esters are used.

Specific examples of the phosphate ester include tricresyl phosphate and tri (2,6-dimethylphenyl) phosphate (PX13 manufactured by Daihachi Chemical Industry Co., Ltd.).
0), triaryl phosphate (Leophos manufactured by Ajinomoto Co., Inc.) and the like can be used, and if desired, two or more kinds can be added. Red phosphorus, which is a simple substance of phosphorus, also has a high flame-retardant effect, and its fine powder, for example, Hishigard CP manufactured by Nippon Chemical Industry Co., Ltd. can be used.

The phosphorus compound used in the present invention is preferably used in the above-mentioned phosphorus content in the range of 0.1 to 2% by weight based on the whole composition.

As described above, the content of phosphorus in the resin composition of the present invention is 0.1 to 2% by weight. If the phosphorus content is low, the flame retardancy cannot be obtained unless the bromine compound is added in a larger amount.Therefore, a large amount of halide decomposition products are generated during soldering and the heat resistance is not sufficient. Electrical insulation deteriorates.

Since the second resin composition of the present invention does not need to be cured with ultraviolet rays, the fifth and sixth components may be omitted.

The resin composition of the present invention and the second resin composition are compositions containing at least the above-mentioned components, and include additives such as a leveling agent, an antifoaming agent, a pigment, an ultraviolet absorber, and an ion scavenger. May be added as needed.

The conventional glass epoxy laminate has a dielectric constant of 1
It is 4.7-5.0 in MHz. The epoxy resin alone has a dielectric constant of 3.7, but it is known that the dielectric constant increases when glass cloth is used as a reinforcing material. The resin composition of the present invention has a dielectric constant of 2.9 to 3.0 at 1 MHz because of the absence of glass cloth and the properties of the resin, which is advantageous for increasing the speed of signal transmission when used as an interlayer insulating material. .

When used as an interlayer insulating material of a thin printed wiring board having a thickness of 0.6 mm or less, when the wiring is heated to a high temperature such as soldering or solder reflow, the printed wiring board is warped and contains no rubber-like fine particles. Without the inorganic filler, the stress generated by the above-mentioned warping due to heating could not be dispersed, and cracks and swelling sometimes occurred in the resin layer sandwiched between the inner and outer copper foils.
However, in the resin composition of the present invention, deformation stress is applied to the resin composition, but the rubber-like fine particles absorb the above-mentioned stress, so that the above-mentioned cracks and blisters do not occur.

The first resin composition of the present invention can be used to form an insulating layer by adjusting the viscosity with a solvent and then directly applying and drying it on an inner layer panel having a conductor circuit pattern. You may apply | coat and dry on a film and may laminate | stack on an inner layer panel as a film-shaped photosensitive resin composition. The latter is preferable in that the surface smoothness of the insulating layer can be easily obtained and the working environment in the processing step of the printed wiring board.

In order to dissolve and roughen the resin fine particles, an aqueous solution of chromate, chromate, permanganate or the like can be used. Preferably, a roughening solution containing a weak alkali or acidic potassium permanganate as a main component is preferable. Here, weak alkali refers to a pH of 10 or less. If the pH exceeds 10, the solution permeates into the entire resin layer and is corroded, so that it is easy to peel off between the resin layers after plating deposition, so that adhesion cannot be obtained. As potassium permanganate solution, sulfuric acid, phosphoric acid,
A mixed solution of an acid such as nitric acid and potassium permanganate, a mixed solution of an acidic halogen acid such as perchloric acid, hypochlorous acid, bromic acid, and periodic acid and potassium permanganate, potassium perchlorate, and perchloric acid Sodium, potassium hypochlorite, sodium hypochlorite, potassium bromate, sodium bromate,
A mixed solution of a halide such as potassium periodate and sodium periodate and potassium permanganate can be used.
The above potassium permanganate solution can be treated at 20 to 40 ° C.

As a step of roughening the surface of the insulating layer made of the resin composition of the present invention, the resin layer is irradiated with ultraviolet rays to provide BVH, the resin in the BVH portion is dissolved and removed with an alkaline solution, and then dried. It is desirable to include a step of polishing the resin surface to expose the soluble fine particles.

Further, when the surface of the resin is roughened with a potassium permanganate solution, dimethylformamide (D
It is desirable to swell by dipping in a highly polar solvent such as MF). Also, DMF is not a stock solution but 1-10%
When pure water is appropriately added, only the vicinity of the surface swells and the adhesive strength is easily obtained.

Next, after roughening the surface of the resin layer, electroless nickel plating of weak alkali or acid is applied. Since the electroless nickel plating layer is provided at the interface between the copper layer to be plated later and the resin layer, the layer serves as a barrier layer, and can prevent the deterioration of copper during heating such as soldering or reflow. The plating thickness is preferably 0.1 μm or more. 0.1 μm
Below, a sufficient barrier effect cannot be obtained. After the electroless nickel plating, electroless copper plating may be performed in order to secure electrical conductivity, and electrolytic copper plating may be further performed thereon. Alternatively, electrolytic copper plating may be performed after electroless nickel plating. However, in that case, it is necessary to increase the thickness of the electroless nickel plating in order to secure electrical conductivity with the nickel layer.

After the electroless nickel plating, before the electroless copper plating and / or the electrolytic copper plating is performed,
Annealing is performed by heating at 00 ° C. for 10 to 60 minutes. The curing of the resin layer that has been semi-cured by the UV irradiation by the annealing process proceeds, and the adhesive force at the interface with the nickel layer is significantly improved. In particular, in the case of electroless copper plating with a strong alkali, the nickel layer serves as a barrier to prevent corrosion of the resin due to the strong alkali.

The entire surface of the inner layer panel after the surface roughening may be subjected to plating such as electroless plating and electrolytic copper plating. The thickness of the plating layer may be varied from several μm to 35 μm as needed. To remove unnecessary copper, an etching resist is formed, and copper is dissolved and removed with an etching solution such as copper chloride or iron chloride, and an outer circuit pattern is formed by stripping the film. Also, after plating over the entire surface, form a plating resist, add copper plating, apply solder plating, tin plating, etc., strip the plating resist, and remove unnecessary copper using solder, tin, etc. as an etching resist Is also good.

[0051]

The present invention will be described in detail below with reference to examples. (Synthesis of Base Polymer) A mixture consisting of 48 parts by weight of methyl acrylate, 29 parts by weight of styrene, 23 parts by weight of acrylic acid and 0.25 parts by weight of azobisisobutyronitrile was kept at a temperature of 75 ° C. under a nitrogen gas atmosphere. The mixture was added dropwise over 5 hours to 100 parts by weight of a mixed solvent having a mixing ratio of methyl ethyl ketone to ethanol of 7: 3. Thereafter, the mixture was aged for 0.5 hour, and further 0.3 parts by weight of azobisisobutyronitrile was added, followed by aging for 4 hours to synthesize an unreacted acrylic polymer. Next, while adding 0.23 part by weight of hydroquinone as a polymerization inhibitor and blowing in a small amount of air, 1.5 parts by weight of N, N-dimethylbenzylamine, 14.7 parts by weight of glycidyl methacrylate, temperature 7
Reaction at 7 ° C. for 10 hours to give a molecular weight of 15,000 to 50,
The first component having a carboxyl group having an acid value of 1.81 meq / g and an unsaturated group content of 0.9 mol / kg was synthesized.

(Preparation of First Resin Composition) The first component synthesized as described above is 30 parts by weight in terms of solid component, 5 parts by weight of polyethylene glycol diacrylate, and a carboxyl group having an average particle size of 0.07 μm. 10 parts by weight of a modified crosslinked acrylic rubber (DHS2 manufactured by Nippon Synthetic Rubber Co., Ltd.), 10 parts by weight of benzoguanamine resin fine particles having an average particle size of 2 μm, brominated bisphenol A-epoxy methacrylate (bromine content in solid content is about 38% ) In terms of solid content, and 40 parts by weight of a photopolymerization initiator (Irgacure 9 manufactured by Ciba-Geigy)
07), 2 parts by weight of a photopolymerization sensitizer (Kayacure EPA manufactured by Nippon Kayaku Co., Ltd.), and 7.0 parts by weight of phosphate ester (Leophos manufactured by Ajinomoto Co., Inc., phosphorus content: 8%). ,
Thermosetting agent (Perhexin 25B manufactured by NOF Corporation)
0 parts by weight and 75 parts by weight of methyl ethyl ketone are mixed well using a homodisper (manufactured by Tokushu Kika Kogyo Co., Ltd.) to prepare a resin composition, and methyl ethyl ketone is added to adjust the viscosity to about 700 cps. The resin varnish was prepared by filtering with a cloth.

(Production of Insulating Sheet) The resin composition of the above example was coated on a 50 μm-thick polyethylene terephthalate (PET) film, which was previously coated on one side with a release agent, on the uncoated surface of the release agent using a bar coater. 70 ° C
After drying for 10 minutes at 110 ° C., the film was further dried at 110 ° C. for 5 minutes to remove the solvent by evaporation, thereby forming a resin layer having a thickness of about 80 μm to form an insulating sheet.

(Preparation of Second Resin Composition) The first component synthesized as described above is 30 parts by weight in terms of solids, 5 parts by weight of polyethylene glycol diacrylate, and a carboxyl group having an average particle size of 0.07 μm. 10 parts by weight of a modified crosslinked acrylic rubber (DHS2 manufactured by Nippon Synthetic Rubber Co., Ltd.), 40 parts by weight of brominated bisphenol A-epoxy methacrylate (bromine content in solid content is about 38%) in terms of solid content, phosphoric acid 7.0 parts by weight of an ester (Leophos manufactured by Ajinomoto Co., Inc., phosphorus content: 8%), 1.0 part by weight of a hardening agent (Perhexin 25B manufactured by NOF Corporation) and 75 parts by weight of methyl ethyl ketone were homodispersed (specialized by Koki Kagaku). Using an industrial product) to prepare a resin composition.
After adjusting the viscosity to about 700 cps by adding methyl ethyl ketone, the mixture was filtered through a 300th filter cloth to prepare a resin varnish.

(Manufacture of copper-clad insulation sheet)
m, the second resin composition was applied to the roughened surface of the copper foil using a bar coater, dried at 70 ° C. for 10 minutes, further dried at 110 ° C. for 5 minutes, and the solvent was removed by evaporation. About 80
An insulating sheet was prepared by forming a resin layer having a thickness of μm.

(Manufacture of Multilayer Printed Wiring Board) A method of manufacturing a multilayer printed wiring board according to the present invention will be described with reference to the drawings. As shown in FIG. 1, after roughening the surface of the conductor pattern 1 of the inner layer panel made of the glass epoxy laminate 2 having a thickness of 0.6 mm and forming a barrier layer up to a thickness of 100 Å by electroless nickel plating, After laminating the above-mentioned insulating sheet at 80 ° C., the PET film was cooled and peeled off to form a first resin layer 3 having a thickness of 50 μm on the conductor pattern.

Next, BV is applied on the resin layer 3 of the inner panel.
200MJ / via a positive film with H pattern
After exposure to ultraviolet radiation under conditions of cm ^2, for 30 seconds development at a pressure of 1.5 kg / cm ² and 1% sodium carbonate solution as a 40 ° C., to expose the resin layer 3 is the inner layer conductor pattern 1 Dissolved to a diameter of 10 as shown in FIG.
BVH4 of 0 μm could be provided. Further 600
The entire panel was irradiated with ultraviolet rays of MJ / cm ² .

Subsequently, the resin was swelled by immersion in dimethylformamide (DMF) to which pure water 10% was added at room temperature for 1 minute, immediately followed by two-step water washing for 30 seconds, and then potassium permanganate 20 g / liter, Sodium chlorate 50
20 g / liter of the solution was adjusted to pH 9.5 with sodium hydroxide.
The inner layer panel was immersed in a potassium permanganate etching solution adjusted to a temperature of 30 ° C. for 10 minutes to roughen the surface of the resin layer 3. Subsequently, after 30 seconds of two-stage water washing, 30 g / liter of stannous chloride and 30% of hydrochloric acid (37% solution) were added to remove the residue of the potassium permanganate solution on the surface.
The mixture was treated with a neutralizing solution containing 0 cc / liter at room temperature for 5 minutes. Further, after 30 seconds of washing with water, immersion in a solution of hydrochloric acid (300 cc / liter) for 1 minute at room temperature, washing with water for 30 seconds, and treatment with a resin layer 3
An anchor having a depth of 2 to 3 μm was formed on the surface of.

Next, after the entire surface of the panel is activated to adsorb palladium, the pH is adjusted to 9.0 and the solution temperature is adjusted to 35 ° C. using an electroless nickel-phosphorus plating solution, and plating is performed for 2 minutes. A nickel-phosphorus plating layer of about 0.15 μm was formed. After nickel plating, the entire panel is 170
An annealing treatment was performed in an oven at 30 ° C. for 30 minutes.

Subsequently, the nickel surface was treated with 5% sulfuric acid for 30 minutes.
After washing for 2 seconds and washing with water, copper sulfate 9g / l, ethylenediaminetetraacetic acid 12g / l, 2,2 'dipyridyl 10mg / l, 37% formaldehyde 3g
Per liter, electroless copper plating at 40 ° C. adjusted to pH 12.5 with sodium hydroxide, plating 0.5 μm, then copper sulfate 60 g / l, sulfuric acid 180 g / l, sodium chloride 0.07 g / l, brightener (Capalside GS818 manufactured by Schering Co., Ltd.) Using a 10 ml / liter electrolytic copper plating solution at 30 ° C., 3A
/ Dm ² plated with current density and without pinholes 2
A plating BVH6 having a deposition thickness of 5 μm was formed (FIG. 3).

Subsequently, a well-known etching resist was formed on the panel on which the plated BVH was formed as described above to remove unnecessary portions of copper, and after stripping the film, baking was performed at 170 ° C. for 30 minutes. Plating BVH6 as shown
Was obtained. At this point, the peel strength of the plated copper pattern was 0.9 kg / cm.

Further, the above inner layer multi-layer panel is subjected to roughening treatment of a plated copper pattern and formation of a barrier layer, lamination of an insulating sheet, exposure and development, surface roughening treatment, and plating to form an inner layer having plating BVH8 over two layers. A multilayer panel was produced (FIG. 5).

Subsequently, as shown in FIG.
After roughening the plated copper pattern of the inner multilayer panel having the VH and forming the barrier layer, the copper clad insulating sheet 12
Is laminated at 80 ° C. and plated on a copper circuit at 50 μm.
A second resin layer 11 and a copper foil 10 having a thickness were formed (FIG. 7).

Next, an etching resist is formed, the copper foil at a predetermined position is etched, and the exposed resin layer is developed with a 1% sodium carbonate solution at 40 ° C. under a pressure of 1.5 kg / cm ² for 50 seconds. Then, the resin layer 11 was dissolved until the inner copper circuit was exposed to provide a BVH 13 having a diameter of 150 μm as shown in FIG.

Subsequently, 9 g / l of copper sulfate, 12 g / l of ethylenediaminetetraacetic acid, 10 mg / l of 2,2′-dipyridyl, 3 g / 37% of formaldehyde
Liter, electroless copper plating at 40 ° C. adjusted to pH 12.5 with sodium hydroxide, plating 0.5 μm,
Using a copper plating solution of 30 g / L of 60 g / L of copper sulfate, 180 g / L of sulfuric acid, 0.07 g / L of sodium chloride, and 10 mL / L of brightener (Kapallaside GS818, Schering Co.) at 3 A / dm.
Plated in ² current density, pinhole-free 25μm
Was formed (FIG. 9).

Subsequently, a well-known etching resist is formed on the panel on which the plated BVH has been formed as described above to remove unnecessary portions of copper, and after stripping the film, baking is performed at 170 ° C. for 30 minutes. Plating BVH as shown
Was obtained. At this point, the peel strength of the outermost copper pattern was 1.6 kg / cm.

Next, the multilayer printed wiring board prepared as described above was evaluated as follows. A test piece having a pattern of 25 mm square was floated in a molten solder bath at a bath temperature of 260 ° C. with the copper foil face down, and the time required for the copper foil to expand was measured. JIS-C50
As a result of measuring the insulation resistance between the outer layer and the inner layer using the M pattern of the test pattern for the multilayer printed wiring board specified in No. ¹² , the initial value is 10 ¹² to 10 ¹³ Ω and after the moisture resistance (C-96 / 40 /
95) was 10 ¹¹ to 10 ¹² Ω. The male mold was set on a mini desk press manufactured by Kamekura Seiki so that it hit the cured resin of the present invention first, and punched with a 2 cm square punching die.
As a result of observing the substrate (2 cm square) which had fallen off and observing the presence or absence of cracks, no crack was found to be favorable. 260 ° C
Immediately after floating in the solder bath for 30 seconds, the presence or absence of cracks in the insulating layer was observed, but no cracks occurred. UL9
As a result of cutting the sample based on No. 4 and conducting a test, all levels of UL94V-0 were obtained. In addition, connection 20
A 100-cycle cooling / heating cycle test was conducted with a cycle of −65 ° C. for 30 minutes and 125 ° C. for 30 minutes to observe the change in conduction resistance of the blind via hole of 0 hole. Rate.

[0068]

According to the resin composition of the present invention, a structure having no reinforcing material such as glass cloth, and excellent adhesiveness, impact resistance and heat resistance of a conductor circuit which cannot be obtained with a conventional acrylic resin. This makes it possible to use a material that has both flame retardancy and insulation reliability, and is suitable for thinning, lightening, and high-speed transmission. In particular, the outermost layer of the copper circuit has a high adhesive strength, and is excellent in mounting reliability, ease of repair, and the like. Further, according to the method for manufacturing a multilayer printed wiring board of the present invention, BVH can be batch-processed by dissolving a resin with an aqueous alkali solution, which can easily provide a favorable working environment, thereby improving productivity. As described above, the present invention can provide a method for manufacturing a multilayer printed wiring board having excellent reliability and excellent mass productivity, and therefore has great industrial value.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing a state in which a first resin layer 2 is formed on an inner layer panel having a copper wiring pattern 1 on a surface in a manufacturing process of a multilayer printed wiring board according to an embodiment of the present invention. is there.

[FIG. 2] In the same manufacturing process, BV is dissolved by alkali dissolution.
It is the schematic sectional drawing which showed the said inner layer board panel after forming H4.

FIG. 3 is a schematic sectional view showing a state where a plating layer 6 is provided in the same manufacturing process.

FIG. 4 is a schematic cross-sectional view showing a state in which a plating layer is selectively etched to form a plating BVH6 inner-layer multilayer panel in the manufacturing process.

FIG. 5: Repeated plating BVH in the same manufacturing process
FIG. 4 is a schematic sectional view showing a state in which a multilayer panel having two layers is formed.

FIG. 6 is a schematic cross-sectional view of a step of laminating a copper-clad insulating sheet 12 on the inner multilayer panel in the same manufacturing process.

FIG. 7 is a schematic cross-sectional view after laminating a copper-clad insulating sheet 12 on the inner multilayer panel in the same manufacturing process.

FIG. 8 is a schematic cross-sectional view showing a state in which BVH 13 is formed by etching the copper foil 10 and dissolving with alkali in the same manufacturing process.

FIG. 9 is a schematic cross-sectional view showing a state where a plating layer is provided in the same manufacturing process.

FIG. 10 is a schematic cross-sectional view showing a state in which a multilayer printed wiring board having a plating BVH is formed by selectively etching a plating layer in the same manufacturing process.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 conductor pattern 2 laminate 3 first resin layer 4 BVH 5 plating layer 6 plating BVH 7 copper circuit 8 plating BVH 10 copper foil 11 second resin layer 12 copper-clad insulating sheet 13 BVH 14 plating BVH

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5E343 AA15 AA17 BB18 BB24 CC61 DD43 DD44 DD76 EE37 ER43 ER46 5E346 AA02 AA12 AA15 AA43 AA54 CC04 CC08 CC09 CC32 CC37 DD02 DD03 DD23 DD32 DD33 EE33 FF04 FF07 GG17GG13FF HH11 HH18

Claims (3)

[Claims] (1) After roughening the surface of a conductor pattern of an inner layer plate having a conductor pattern, a first material having active energy ray curability on the inner layer plate and having insulation and heat resistance after curing. Forming a resin layer; (2) irradiating a predetermined position of the first resin layer with an active energy ray to cure an irradiated portion, and then dissolving the unirradiated portion of the resin layer to form a blind via hole; Providing step; (3) roughening the surface of the cured first resin layer; (4) forming a metal layer on the resin layer surface and blind via holes by plating; (5) conducting on the surface Forming a pattern; (6)
If necessary, repeating steps (1) to (5) to form a multilayer panel; (7) roughening the surface of the conductor pattern; (8) electron beam curability and / or thermosetting Laminating a copper-clad insulating sheet, in which a second resin layer having insulation and heat resistance after curing is previously applied to a roughened surface of a copper foil, on the panel or the multilayer panel; (9) blind via A step of dissolving the copper foil in the hole portion and the second resin layer thereunder; (10) a step of curing the second resin layer; (11) a step of forming a metal layer by plating; and (12) a conductor on the surface. Forming a pattern; a method for producing a multilayer printed wiring board. 2. The method according to claim 1, wherein the first resin layer has alkali solubility and ultraviolet curability, and the second resin layer has alkali solubility and has electron beam curability and / or thermosetting property. The method for manufacturing a multilayer printed wiring board according to claim 1. 3. An acrylic and / or methacrylic resin in which the first resin layer has a carboxyl group, crosslinked rubber-like fine particles having a carboxyl group, benzoguanamine-based resin fine particles, a crosslinking agent by active energy and / or heat, and ultraviolet polymerization. An acrylic and / or methacrylic polymer having a carboxyl group and a crosslinked rubber having a carboxyl group, wherein the second resin layer comprises a resin composition comprising an initiator, a sensitizer for ultraviolet polymerization, a thermosetting agent, and a flame retardant. Microparticles, benzoguanamine-based resin microparticles, a cross-linking agent by active energy and / or heat,
The method for producing a multilayer printed wiring board according to claim 1, comprising a resin composition comprising a flame retardant.