JPH11261219A - Manufacture of build-up multilayered printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method by which a high-density build-up multilayered wiring board in which fine conductor patterns can be formed easily and which has high parts mountability and connection reliability can be manufactured efficiently. SOLUTION: A build-up multilayer printed wiring board is manufactured in such a way that a conductor pattern 31 is formed by selectively etching the first copper layer 301 of composite metal foil composed of the copper layer 301, a nickel-phosphorus alloy layer 302, and a second copper layer 303 and a thermosetting insulating resin layer containing a filler is formed on the surface of the pattern 31. Then a strippable organic film 4 is formed on the surface of the insulating resin layer and a non-through hole 7 reaching the surface of the pattern 31 is formed through the insulating resin layer and film 4 at a location proposed for electrical connection with a laser beam. After the formation of the hole 7, the hole 7 is filled up with conductive paste 71 and the organic film 4 is stripped off. Then a laminated body is obtained by putting the insulating resin layer on an innerlayer circuit and pressurizing and heating the layer and board and only the second copper layer 303 and nickel-phosphorus alloy layer 302 are removed from the laminated body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a multilayer printed wiring board in which electrical connection between layers is performed using a conductive paste.

[0002]

2. Description of the Related Art In recent years, electronic devices have been further reduced in size, weight, and multifunctionality, and with this, LSIs, chip components, and the like have become more highly integrated. And it is changing rapidly. For this reason, a multilayer printed wiring board has been required to further increase the wiring pattern density in order to increase the mounting density of electronic components. In order to satisfy these demands, thinning between layers, miniaturization of wiring, and reduction in diameter of interlayer connection holes are performed, and interstitial via holes (hereinafter, referred to as IVH) that connect only conductors between adjacent layers. ) And buried via holes (hereinafter referred to as BVH).
VH and BVH are also being reduced in diameter.

In order to increase the number of wiring layers, usually, a plurality of circuit layers and an interlayer insulating layer therebetween are collectively stacked, laminated by heating and pressing, and a hole is formed at a required position. There is a build-up method in which an interlayer insulating layer is formed thereon, a circuit is formed thereon, holes are provided in necessary places, and a circuit layer and an insulating layer are sequentially formed.

As an example of this build-up method, a thermosetting insulating resin or a conductive resin is filled in a through hole of an inner circuit board having a plated through hole and an inner layer circuit formed thereon by a silk screen printing method or the like. So buried,
After heating and curing, remove the thermosetting insulating resin protruding from the hole by polishing, apply a thermosetting thermosetting insulating resin, overlay copper foil, heat and cure to form an insulating layer. After forming and selectively removing a part of the copper foil, a hole for interlayer connection is provided by selectively removing the insulating layer at that location, and metallizing the inner wall of the hole for interlayer connection by plating. And forming a circuit conductor on the insulating layer,
Further, a circuit is formed. By using the formed circuit as an inner-layer circuit board, one more insulating layer and a circuit layer can be formed by the same operation as described above. A multi-layer circuit can be formed.

[0005]

In order to manufacture a multilayer printed wiring board by such a build-up method, a thermosetting insulating board is formed before forming a build-up layer on an inner circuit board having through holes. It is necessary to fill the inside of the through hole with resin or conductive resin, and there are curtain filling method, screen printing method, dip method and film laminating method as the filling method, but is it difficult to fill with these methods? Or, even if the filling is completed, it is necessary to remove the excess resin on the substrate surface by mechanical polishing, and the mechanical polishing causes a change in the size of the inner layer circuit, so that there is a problem that a positional shift occurs and the yield decreases. .

Further, when forming a via hole, a hole for interlayer connection is provided by selectively removing an interlayer insulating layer from a portion of the copper foil forming the via hole, and the interlayer connection hole is formed by plating. While metalizing the inner wall of the hole, forming a conductor for the circuit on the insulating layer and etching away the unnecessary conductor to form the circuit, the conductor to be formed has a thickness of copper foil and plating, There is a problem that it becomes difficult to form fine wiring by selective etching removal of the conductor.

In addition, since the holes for interlayer connection are recessed, in the case of further multilayering, it is necessary to fill and smooth the recess once with a filling resin or the like before forming an interlayer insulating layer. There was a problem that the process became complicated.

In the above-described conventional method, a wiring board for mounting a component having a large number of connection terminals arranged at a narrow pitch, such as an IC of a quad flat package (hereinafter referred to as QFP), is manufactured. In this case, the wiring cannot be drawn out from the terminal of the QFP with one wiring layer, and it is necessary to draw out the wiring over two or more layers. In such a case, the land on the surface of the wiring board connected to the terminal of the QFP is required. In some cases, it is necessary to provide a connection land at the pulled-out location, form an IVH, connect to the inner layer, and further form an IVH connected to the inner layer inside the inner layer at the same location. In this case, it is difficult to fill the solder resist and the precision of positioning the solder resist and the terminals becomes strict. Further, when an IVH hole is formed directly on a land on the surface of a wiring board connected to a terminal of a QFP, the solder is not completely filled in the IVH hole, and voids of the solder are generated, thereby lowering connection reliability. I was

It is an object of the present invention to provide a method for efficiently forming a high-density build-up multilayer printed wiring board which enables easy formation of a fine conductor pattern, is excellent in component mounting, and is excellent in connection reliability. It is the purpose.

[0010]

A method of manufacturing a build-up multilayer printed wiring board according to the present invention is characterized in that the following steps are performed in this order. a. As shown in FIG. 1A, a first copper layer 301 having roughness suitable for bonding to a resin and serving as a circuit, and a second copper layer having sufficient strength as a metal layer as a whole In the composite metal foil 3 composed of the layer 303 and the nickel-phosphorus alloy layer 302 provided between the two layers, only unnecessary portions of the first copper layer 301 are removed by etching. As shown, a step of forming a conductor pattern 31. b. As shown in FIG. 1C, a step of forming a thermosetting insulating resin layer 2 containing a filler on the surface of the conductor pattern 31 of the composite metal foil 3 to form a material for a multilayer wiring board. c. As shown in FIG. 1D, a step of providing a peelable organic film 4 on the surface of the thermosetting insulating resin layer 2 of the material for a multilayer wiring board. d. As shown in FIG. 1 (e), at a place where electrical connection between layers on the side of the surface of the organic film 4 of the material for a multilayer wiring board is performed,
A step of irradiating a laser to form a non-through hole 7 reaching the surface of the conductor pattern 31; e. As shown in FIG. 1F, a step of filling the non-through hole 7 with a conductive paste 71. f. As shown in FIG. 1 (g), from the material for the multilayer wiring board,
Step of peeling off the organic film 4. g. As shown in FIG. 1 (h), the thermosetting insulating resin layer 2 of the material for a multilayer wiring board manufactured in the step f is overlapped on the surface of the inner circuit board 1 in which the through holes 11 are formed. A step of aligning the connection position between the conductive paste 71 and the inner layer circuit board 1 and applying pressure and heat to laminate and integrate as shown in FIG. 1 (i). h. As shown in FIG. 1 (j), a step of removing only the second copper layer 303. i. As shown in FIG. 1 (k), the nickel-phosphorus alloy layer 3
Step of removing only 02.

In addition, the following steps can be performed instead of the steps b and c. b1. A step of forming a thermosetting insulating resin layer 2 containing a filler on a peelable organic film 4 to form a thermosetting insulating resin layer with a carrier. c1. The thermosetting insulating resin layer with the carrier is formed in step a
Laminating on the surface of the conductor pattern 31 of the composite metal foil 3 prepared in the above.

It is preferable to use an electrically insulating ceramic whisker as a filler compounded in the thermosetting insulating resin layer, and the compounding amount of the filler is preferably 5 to 50 vol%.

Further, the multilayer printed wiring board manufactured up to the step i as shown in FIG. 2A is used as the second inner layer circuit board 8, and the steps a to i are further repeated as necessary. For example, as shown in FIG. 2B, a build-up multilayer printed wiring board can be manufactured. In addition, a laser beam is applied to a portion where the connection of the second inner circuit board 8 is performed, and the via hole 8 reaching the inner circuit board 1 is formed.
1 and plating the surface thereof to form a circuit conductor 82 of a required shape as a third inner-layer circuit board 9, and repeating the steps a to i as many times as necessary, for example, As shown in FIG. 2C or 2D, a build-up multilayer printed wiring board can be manufactured.

(Composite Metal Foil) The composite metal foil of the present invention includes:
A first copper layer having a roughness suitable for adhesion to a resin and serving as a circuit, a second copper layer having a strength sufficient for handling as a whole metal layer, and an intermediate layer provided between the two layers. The nickel-phosphorus alloy layer is formed by, for example, performing a roughening treatment using an oxidizing agent on one surface of a copper foil serving as a second copper layer, and oxidizing the same by a reducing agent. It can be produced by reducing copper to metallic copper while maintaining its roughened shape, plating the surface with a nickel-phosphorus alloy, and further performing copper plating. The thickness of the first copper layer is preferably in the range of 0.5 to 25 μm, and more preferably in the range of 1 to 9 μm. If it is less than 0.5 μm, the thickness of the circuit conductor will vary greatly, and if it exceeds 25 μm, fine wiring may not be formed. The thickness of the nickel-phosphorus alloy layer is preferably in the range of 0.01 to 3 μm, and more preferably in the range of 0.04 to 1.5 μm. When the thickness is less than 0.01 μm, it may not be possible to protect the first copper layer from being etched when only the second copper layer is removed by etching,
If the thickness is more than 3 μm, the selective etching removability of the nickel-phosphorus alloy layer after heating during the laminating and bonding with the thermosetting insulating resin layer is reduced, and a phenomenon that the etching cannot be removed cleanly occurs. The thickness of the second copper layer is
It is preferably at least 5 μm, more preferably from 10 to 150 μm. If it is less than 5 μm, sufficient strength for handling as a whole metal layer cannot be obtained,
If the thickness is too large, the efficiency at the time of removing by etching decreases, which is not preferable.

(Thermosetting Insulating Resin) As the thermosetting insulating resin of the present invention, it is particularly preferable to use a thermosetting resin. For example, the blending equivalent ratio of a difunctional epoxy resin and a halogenated difunctional phenol is preferable. Is an epoxy group / phenol hydroxyl group = 1 / 0.9 to 1.1, and is heated and polymerized in the presence of a catalyst to form an epoxy polymer having a molecular weight of 100,000 or more, a crosslinking agent, and a polyfunctional epoxy resin. It is possible to use either a thermosetting epoxy resin having a film forming ability as described above or a resin having no film forming ability alone. Here, the film-forming ability means that the resin is dissolved in a solvent to form a varnish, the thickness of which is easily controlled when the varnish is applied to a carrier film, and which is heated and dried to have a semi-cured state. It refers to the ability to hardly cause cracking or chipping of resin when transporting, cutting and laminating, and to ensure the minimum thickness as an insulating layer during the subsequent heat and pressure molding.

As the thermosetting insulating resin having no film forming ability by itself, there is a resin which has been conventionally used by impregnating a glass cloth, for example, a resin having a molecular weight of not more than 30,000, Resins, bismaleimide triazine resins, polyimide resins, phenol resins, melamine resins, silicon resins, unsaturated polyester resins, cyanate ester resins, isocyanate resins, and modified resins thereof. Above all, epoxy resin, bismaleimide triazine resin, and polyimide resin are Tg
It has high elasticity and hardness and is therefore preferable. As the epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, phenol novolak epoxy resin, cresol novolak epoxy resin, bisphenol A novolak epoxy resin, salicylaldehyde novolak epoxy resin, bisphenol F novolak epoxy resin, Uses alicyclic epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, hydantoin type epoxy resin, isocyanurate type epoxy resin, aliphatic cyclic epoxy resin and their halides and hydrogenated products It can be used together. Among them, bisphenol A novolak type epoxy resin and salicylaldehyde novolak type epoxy resin are excellent in heat resistance and are preferable.

(Electrically Insulating Ceramic Whisker) As a filler that can be used in the present invention, there is an electrically insulating ceramic whisker. Examples of such an electrically insulating ceramic whisker include aluminum borate,
It can be used by selecting from wollastonite, potassium titanate, basic magnesium sulfate, silicon nitride, and α-alumina. Among them, aluminum borate and potassium titanate have a Mohs hardness similar to that of conventional E glass. Thus, a wire bonding property equivalent to that of a conventional prepreg is obtained, and furthermore, aluminum borate is preferable because it has a high elastic modulus of 400 MPa and is easily mixed with varnish.

The shape of the electrically insulating ceramic whisker preferably has an average diameter of 0.3 to 3 μm and an average length of at least 5 times the average diameter. The average diameter is
If it is less than 0.3 μm, mixing with the resin varnish becomes difficult, and if it exceeds 3 μm, dispersion in the resin is not sufficient,
The unevenness of the applied surface becomes large. This average diameter is
The range of 0.3 to 1 μm is more preferable.

If the average length is less than 5 times, rigidity of the resin cannot be obtained, and more preferably 20 times or more. In addition, the upper limit is preferably 50 μm or less, and this numerical value is preferably smaller than the circuit interval between the inner layer circuits. When this average length exceeds the interval between the inner layer circuits, when the two circuits come into contact with each other, It is not preferable because ion migration of copper easily occurs along the electrically insulating ceramic whisker, and there is a high possibility of short circuit.

In order to increase the wettability between the electrically insulating ceramic whisker and the thermosetting insulating resin, it is preferable to use an electrically insulating ceramic whisker whose surface is treated with a coupling agent. Coupling agents include silicon-based coupling agents, titanium-based coupling agents, aluminum-based coupling agents, zirconium-based coupling agents, zirconium-based coupling agents, chromium-based coupling agents, boron-based coupling agents, and phosphorus-based coupling agents. It can be used by selecting from a system-based coupling agent, an amino-based coupling agent and the like.

(Curing Agent) As the curing agent used for the thermosetting insulating resin of the present invention, any curing agent can be used as long as it is used for the above-mentioned resin. Of these, dicyandiamide, bisphenol A, bisphenol F, polyvinyl phenol resin, novolak resin, and bisphenol A novolak resin are preferable because of their excellent heat resistance. The mixing ratio of this curing agent to the thermosetting insulating resin is 100%.
With respect to parts by weight, a range of 2 to 100 parts by weight is preferable,
If it is dicyandiamide, the range is more preferably 2 to 5 parts by weight, and if it is the other curing agent, the range is 30 to 80 parts by weight. If the amount is less than 2 parts by weight, curing will be insufficient, and the heat resistance will decrease. If it exceeds 100 parts by weight, the electrical properties and heat resistance will decrease.

(Curing Accelerator) A curing accelerator can be further used in the thermosetting insulating resin and the curing agent of the present invention. When the thermosetting resin is an epoxy resin, the curing accelerator is , Imidazole compounds, organic phosphorus compounds, tertiary amines, quaternary ammonium salts, and the like. The compounding ratio of the curing accelerator is preferably in the range of 0.01 to 20 parts by weight, more preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the thermosetting insulating resin.
If the amount is less than 0.01 part by weight, the curing becomes insufficient and the heat resistance is reduced. If the amount exceeds 20 parts by weight, the life of the B stage is shortened and the heat resistance is reduced.

(Diluent) The thermosetting insulating resin, the electrically insulating ceramic whisker, the curing agent, and the curing accelerator are used after being diluted with a solvent, and the solvent includes acetone, methyl ethyl ketone, toluene, xylene, methyl Isobutylene, ethyl acetate, ethylene glycol monomethyl ether, methanol, ethanol, N, N-dimethylformamide, N, N-dimethylacetamide and the like can be used. The mixing ratio of the diluent to the thermosetting insulating resin is 1 to 100 parts by weight of the thermosetting insulating resin.
A range of 200 parts by weight is preferable, and a range of 30 to 100 parts by weight is more preferable. If the amount is less than 1 part by weight, the viscosity becomes high and coating unevenness is likely to occur. If the amount is more than 200 parts by weight, the viscosity becomes so low that it cannot be applied to a required thickness.

(Ratio of thermosetting insulating resin to electrically insulating ceramic whisker) The ratio of thermosetting insulating resin to electrically insulating ceramic whisker is determined by the ratio of the electrically insulating ceramic whisker in the cured thermosetting insulating resin. Whisker is 5-50v
It is necessary to adjust so as to be ol%. Further, the content is more preferably 20 to 40% by volume. 5
When the content is less than vol%, the thermosetting insulating resin has a small film-forming ability, is difficult to handle such as being scattered at the time of cutting, has low rigidity, has a large warp after component mounting, and deteriorates mountability. If it exceeds 50% by volume, filling in holes and circuit gaps in the inner layer circuit board is insufficient at the time of molding under heat and pressure, resulting in voids and blurring after molding, resulting in reduced insulation.

(Peelable Organic Film) A peelable organic film needs to be easily processed by a laser used to form a non-penetrating hole. From this point, an organic film is preferable, and polyethylene terephthalate, polypropylene, poly-4-methylpentene-
1. Polyfluoroethylene, polyethylene, polyvinyl chloride and the like can be used. Lasers are used to drill non-through holes. Lasers include excimer laser, carbon dioxide gas laser, YAG laser, etc.
A carbon dioxide laser that balances processing quality, processing cost, and the like is preferable.

(Conductive paste) As the conductive paste to be filled in the non-through holes, a thermosetting conductive paste containing conductive particles such as metal particles, a conductive organic substance, and carbon, or an ultraviolet curable and thermosetting paste is used. A conductive paste having a combined property, and a thermoplastic conductive paste mixed with conductive particles such as metal particles, conductive organic substances, and carbon can also be used. These conductive pastes are filled into the non-through holes by printing or the like, and remove the peelable film after printing.

(Inner Circuit Board) As the inner circuit board used in the present invention, an epoxy-based, phenol-based, or polyimide-based double-sided metal-clad laminate containing a paper base or a glass base can be used. A single-sided metal-clad laminate composed of a base material and a resin can be used. Holes are formed in these laminates, the inner walls of the holes are metallized, and unnecessary conductors are removed by etching to form an inner circuit. In addition, a substrate in which a conductive pattern is formed only on a portion to be an inner layer circuit of an insulating substrate in which a paper substrate or a glass cloth substrate is impregnated with an epoxy resin, a phenol resin, or a polyimide resin can be used. In addition, a metal substrate, a ceramic substrate, or the like having a conductive pattern formed on the surface thereof can also be used.

[0028]

DETAILED DESCRIPTION OF THE INVENTION Step a. In this step, in order to form an etching resist, a method used for a normal printed wiring board can be used, for example, a method of printing a peelable resist ink on the surface of a copper foil by a silk screen printing method, A method of laminating a resist film on the surface of a copper foil, irradiating an ultraviolet ray through a photomask so that a resist can be formed on a circuit portion, and developing and removing a circuit gap portion can be used. At this time, it is preferable to form an etching resist also on the entire surface of the second copper layer on the back surface to prevent the second copper layer from being etched.

As a solution for etching and removing only the first copper layer, a solution containing chlorine ions, ammonium ions and copper ions (hereinafter referred to as an alkali etchant) is used. A method of contacting with a solution is used. The etching resist is removed by using a solvent or an alkaline aqueous solution.

Step b. In this step, in order to form a thermosetting insulating resin layer on the metal foil on which the conductor pattern has been formed, a solution obtained by mixing the thermosetting insulating resin, a curing agent, a curing accelerator, and a diluent (hereinafter referred to as a thermosetting resin) is used. A varnish with stirring was applied to a curable insulating resin varnish.)
It can be semi-cured, and can apply a shearing force in the direction parallel to the copper foil, such as a blade coater, rod coater, knife coater, squeeze coater, reverse roll coater, or transfer roll coater, or can be perpendicular to the plane of the copper foil. It is preferable to select a coating method capable of applying a compressive force in the direction. To add a filler to the thermosetting insulating resin, the thermosetting insulating resin, a curing agent, a curing accelerator,
For example, an electrically insulating ceramic whisker is mixed with a solution (hereinafter, referred to as a thermosetting insulating resin varnish) in which the varnish is mixed to obtain a varnish.

Step c. In this step, the peelable organic film is heated and pressed by a press, a roll laminator, or the like to be laminated and temporarily bonded. The press temperature at this time is
Although it depends on the peelable organic film to be used, for example, PET is preferably performed at 110 ° C. for 15 minutes at 2.5 MPa, under conditions where the thermosetting insulating resin is not completely cured.

Step d. In this step, lasers that can be used include a carbon dioxide laser, a YAG laser, an excimer laser, and the like, and a carbon dioxide laser that is balanced in terms of processing speed, processing quality, and processing cost is preferable. The irradiation condition of the laser beam at this time is preferably such that the pulse is oscillated with a short time and a large output. For example, the width of one pulse is 1 to 40 μsec and the pulse repetition frequency is 150.
-10,000 Hz, the number of repetition pulses is 1-10 pulses, and the output magnitude is 2-5 pulses.
A laser oscillator capable of producing an output capable of drilling holes is preferable because oscillation and control are easy. This output is in the range of 15 to 40 J / cm ² in terms of energy density. If the output per time is less than the above range, the resin layer cannot be evaporated and diverged.If the output exceeds the above range, the hole diameter becomes more than necessary and control is difficult, and the once evaporated resin is carbonized. It may adhere, and the attached carbide must be removed.

Step e. In this step, as the conductive paste to be filled in the non-through holes, a thermosetting conductive paste mixed with conductive particles such as metal particles, a conductive organic substance, or carbon, or a conductive paste mixed with ultraviolet curing and thermosetting is used. As the conductive paste, a thermoplastic conductive paste mixed with conductive particles such as metal particles, conductive organic substances, and carbon can also be used. As a filling method, a normal silk screen printing method can be applied.

Step f. In this step, as a method of peeling the peelable organic film formed in step c,
It can be peeled off mechanically and easily peeled off by hand.

Step g. In this step, the connection lands of the inner layer circuit board and the outer layer multi-layer laminating material obtained in step f are aligned and overlapped, and heated and pressurized to simultaneously perform through-holes and multi-layer lamination. The multilayer lamination conditions vary depending on the resin composition used, but are 140 to 190 ° C and 2 to 4MP.
a, 30 to 150 minutes are standard conditions.

Step h. In this step, as the solution for etching and removing only the second copper layer, the same alkali etchant as that used for etching the first copper layer can be used.
Similarly, it can be carried out by contact with a solution such as dipping or spraying.

Step i. In this step, in order to remove only the nickel-phosphorus alloy layer, an organic acid having a carboxyl group as an additive and -NH- and -N as ring members are added to a liquid containing nitric acid and hydrogen peroxide as main components. It is immersed in an aqueous solution containing a heterocyclic compound containing nitrogen in the form of = or sprayed with such an aqueous solution.

[0038]

EXAMPLE 1 As shown in FIG. 1 (h), an MCL which is a glass cloth-epoxy resin impregnated double-sided copper-clad laminate having a thickness of 0.4 mm was previously prepared.
Using -E-679 (trade name, manufactured by Hitachi Chemical Co., Ltd.), drilling and electroless copper plating were performed, and an inner layer circuit board 1 having through holes 101 was produced by a normal subtraction method. 5 μm thickness as shown in FIG.
First copper layer / 0.2 μm thick nickel-phosphorus alloy layer /
An etching resist is formed on the surface of the first copper layer of the composite metal foil 3 made of the second copper layer having a thickness of 15 μm by a normal subtraction method, and as shown in FIG. A conductive liquid 31 was formed using an A process liquid (trade name, manufactured by Meltex Co., Ltd.), the etching resist was peeled off with a 3 wt% sodium hydroxide aqueous solution, and as shown in FIG. A thermosetting insulating resin varnish having the following composition is applied to the surface of the copper layer 1 with a knife coater, dried at 150 ° C. for 10 minutes, and semi-cured to obtain a copper foil having a thermosetting insulating resin 2 having a thickness of 50 μm. As shown in FIG. 1 (d), a 15 μm-thick polyethylene terephthalate film as a peelable organic film 4 was roll-laminated as shown in FIG. 1 (d). To prepare a multi-layer wiring board materials that are bonded together with. (Composition of thermosetting insulating resin varnish) Bisphenol A novolak type epoxy resin 100 parts by weight (Epoxy equivalent: 200) Bisphenol A novolak resin 60 parts by weight (hydroxyl equivalent: 106) 2-ethyl-4-methylimidazole (curing agent) 0.5 parts by weight Methyl ethyl ketone (diluent) ········ 100 parts by weight · Aluminum borate whisker ······ 30 vol% e) As shown in carbon dioxide impact laser drilling machine GS
500 (manufactured by Sumitomo Heavy Industries, Ltd., trade name)
Energy density 20 J / cm ² , oscillation time 1 μsec,
Under the conditions of an oscillation frequency of 150 Hz and a pulse number of 5 shots,
By irradiating a laser beam to remove the resin at the part where the interlayer connection is made, a material for a multilayer wiring board having a non-through hole 7 with a diameter of 0.15 mm reaching the copper foil is produced, as shown in FIG. 1 (f). Then, a conductive paste was filled from above the organic film 4 by a silk screen printing method, and the polyethylene terephthalate film as the organic film 4 was peeled off as shown in FIG. Inner layer circuit board 1 produced in this manner
1H, the circuit conductors of the inner circuit board 1 and the circuit conductors of the adhesive film are aligned with each other, as shown in FIG. Are placed in contact with each other, and at 170 ° C. for 90 minutes, 2.5MP
Heating and pressurizing at the pressure of a, as shown in FIG.
Laminated and integrated. Under these conditions, the resin flow becomes 3
mm. Thereafter, as shown in FIG. 1 (j), only the second copper layer was etched away with a commercially available alkaline etchant A process liquid (trade name, manufactured by Meltex Co., Ltd.). Only 302 was removed by etching with the following etching solution, and FIG.
As shown in (1), a multilayer printed wiring board was produced. (Nickel-phosphorus etching solution composition) ・ Nitric acid ・ ・ ・ ・ ・ ・ ・ ・ 200g / l ・ Hydrogen peroxide solution (35%) ・·········· 10 ml / l ・ Organic acid containing carboxyl group (DL-malic acid) ··· 100 g / l · Benzotriazole ··· ... 5 g / l

Example 2 The same procedure as in Example 1 was carried out except that 10 vol% of aluminum borate whiskers were mixed and stirred with the thermosetting insulating resin varnish. Laser drilling conditions were a carbon dioxide gas laser with an energy density of 20 J / cm ² , an oscillation time of 1 μsec, an oscillation frequency of 150 Hz, and a pulse number of 3.

Example 3 The same procedure as in Example 1 was carried out except that 45 vol% of aluminum borate whiskers were mixed and stirred with the thermosetting insulating resin varnish. Laser drilling conditions were a carbon dioxide gas laser with an energy density of 20 J / cm ² , an oscillation time of 1 μsec, an oscillation frequency of 150 Hz, and a pulse number of 7.

Comparative Example 1 Instead of the adhesive film of Example 1, a film coated with a thermosetting varnish not containing the following filler was used. (Composition of thermosetting insulating resin varnish) Bisphenol A novolak type epoxy resin 100 parts by weight (Epoxy equivalent: 200) Bisphenol A novolak resin 60 parts by weight (hydroxyl equivalent: 106) 2-ethyl-4-methylimidazole (curing agent) 0.5 parts by weight Methyl ethyl ketone (diluent) ........... 100 parts by weight

Comparative Example 2 A composite metal foil having a circuit formed thereon was prepared by applying a thermosetting insulating resin varnish not containing the following filler to a glass cloth cloth and using an impregnated prepreg instead of the adhesive film of Example 1. And a multilayer printed wiring board was produced in the same manner as in Example 1. (Composition of thermosetting insulating resin varnish) Bisphenol A novolak type epoxy resin 100 parts by weight (Epoxy equivalent: 200) Bisphenol A novolak resin 60 parts by weight (hydroxyl equivalent: 106) 2-ethyl-4-methylimidazole (curing agent) 0.5 parts by weight Methyl ethyl ketone (diluent) ........... 100 parts by weight

The following test was performed on the substrate manufactured as described above. Table 1 shows the results. (Test)-Gas phase thermal shock test Thermal shock tester Thermal shock chamber TSR-10
3 (manufactured by TABAI, trade name) at -65 ° C for 30 minutes
One cycle was performed at 125 ° C. for 30 minutes, and the change in connection resistance was measured. The connection resistance was measured using a Hewlett-Packard multimeter 3457A.

[0044]

[Table 1] Fine wiring formability ×: L / S = 50 μm / 50 μm Wiring not possible ○: L / S = 50 μm / 50 μm Wiring possible ◎: L / S = 20 μm / 20 μm Wiring possible Gas phase thermal shock test ×: 500 cycles or less導 通: Conduction resistance change rate of 10% or more 導 通: 500 cycles or more, but less than 1000 cycles Conduction resistance change rate of 10% or more ：: 1000 cycles or more, conduction resistance change rate of less than 10%

[0045]

As described above, the thickness between layers can be reduced.
It is possible to provide a multilayer printed wiring board excellent in miniaturization of wiring, miniaturization of BVH, excellent connection reliability, and excellent productivity, and a method of manufacturing the same.

[Brief description of the drawings]

FIGS. 1A to 1K are cross-sectional views showing respective steps for explaining one embodiment of the present invention.

FIGS. 2A to 2D are cross-sectional views showing another embodiment of the present invention.

[Explanation of symbols]

1. Inner layer circuit board 11. Through hole 2. 2. Thermosetting insulating resin layer Composite metal foil 31. Conductor pattern 301. First copper layer 302. Nickel-phosphorus alloy layer 303. 3. second copper layer Organic film 7. Non-through hole 71. 7. Conductive paste Second inner circuit board 81. Via hole 9. Third inner layer circuit board

 ──────────────────────────────────────────────────の Continuing on the front page (72) Masao Sugano, 1500 Ogawa, Oji, Shimodate, Ibaraki Pref.Hitachi Chemical Industry Co., Ltd. (72) Inventor: Shoji Nakaso, Shimodate, Ibaraki Prefecture 1500 Ogawa, Hitachi Chemical Co., Ltd.

Claims (6)

[Claims] 1. A method for manufacturing a build-up multilayer printed wiring board, wherein the following steps are performed in this order. a. A first copper layer having a roughness suitable for adhesion to a resin and serving as a circuit, a second copper layer having a strength sufficient for handling as a whole metal layer, and an intermediate layer provided between the two layers. Of a composite metal foil comprising a nickel-phosphorus alloy layer,
Forming a conductive pattern by etching and removing only unnecessary portions of the first copper layer; b. A step of forming a thermosetting insulating resin layer containing a filler on the surface of the conductor pattern of the composite metal foil to form a material for a multilayer wiring board. c. A step of providing a peelable organic film on the surface of the thermosetting insulating resin layer of the material for the multilayer wiring board. d. A step of irradiating a laser at a place where electrical connection between layers on the side of the organic film of the material for a multilayer wiring board is made to form a non-through hole reaching the surface of the conductive pattern. e. A step of filling the non-through holes with a conductive paste. f. A step of peeling an organic film from a material for a multilayer wiring board. g. On the surface of the inner layer circuit board with the through hole formed,
A step of stacking the thermosetting insulating resin layers of the multilayer wiring board material prepared in the step f so as to be in contact with each other, aligning the connection positions of the conductive paste and the inner layer circuit board, and pressing and heating to laminate and integrate . h. Removing only the second copper layer; i. Removing only the nickel-phosphorus alloy layer; 2. The method for producing a build-up multilayer printed wiring board according to claim 1, comprising the following steps instead of the steps b and c. b1. A step of forming a thermosetting insulating resin layer containing a filler on a peelable organic film to form a thermosetting insulating resin layer with a carrier. c1. The thermosetting insulating resin layer with the carrier is formed in step a
Laminating on the surface of the conductor pattern of the composite metal foil prepared in the above. 3. The build-up according to claim 1, wherein the filler mixed with the thermosetting insulating resin formed on the conductor pattern surface of the composite metal foil is an electrically insulating ceramic whisker. A method for manufacturing a multilayer printed wiring board. 4. The composition according to claim 3, wherein the amount of the electrically insulating ceramic whisker is 5 to 50 vol%.
3. The method for producing a build-up multilayer printed wiring board according to item 1. 5. A step of manufacturing a build-up multilayer printed wiring board by repeating the steps a to i as many times as necessary using the multilayer printed wiring board manufactured up to step i as a second inner layer circuit board. The method for manufacturing a build-up multilayer printed wiring board according to any one of claims 1 to 4, wherein 6. A via hole reaching the inner circuit board is formed by irradiating a laser beam to a portion where the second inner circuit board is to be connected, and plating is performed on the surface to form a circuit conductor having a required shape. 5. The method according to claim 1, further comprising the step of manufacturing the build-up multilayer printed wiring board by repeating the steps a to i as many times as necessary by using the formed one as a third inner-layer circuit board. The method for producing a build-up multilayer printed wiring board according to any one of the above.