JP2776886B2 - Multilayer printed wiring board and method of manufacturing the same - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer printed wiring board and a method for manufacturing the same, and more particularly, to a method in which a conductor layer of an inner circuit is a via hole (Intersti).
This is a proposal for a method of manufacturing a multilayer printed wiring board having excellent connection reliability for those connected via a tial via hole.

[Conventional technology]

It is important that the conductor layer and the insulating layer of the multilayer printed wiring board are firmly bonded. For this reason, conventionally, various techniques for firmly bonding the conductor layer and the insulating layer have been proposed. For example, (1) a method of firmly bonding the conductor layer and the insulating layer by oxidizing and roughening the surface of the copper forming the conductor layer with an alkaline aqueous sodium chlorite solution or permanganic acid.

(2) The surface of copper forming the conductor layer is oxidized to cupric oxide using an aqueous solution of alkaline sodium chlorite, an aqueous solution of alkaline potassium persulfate, or an aqueous solution of potassium sulfide-ammonium chloride, and then reduced. A method disclosed in Japanese Patent Publication No. Sho 64-8479, in which the surface of the conductor layer is roughened, thereby firmly bonding the conductor layer and the insulating layer.

(3) By forming a composite plating layer containing fine particles of thermosetting resin cured in advance on the surface of the conductor layer, the conductor layer and the insulating layer are firmly adhered to each other.
No. 18 discloses a method disclosed therein.

[Problems to be solved by the invention]

However, in the method (1), since the surface of the same layer is covered with the copper oxide, when the upper and lower conductor layers are joined via the via holes, the via hole connection reliability is low. There were drawbacks.

According to the method (2), although the copper oxide on the surface of the conductor layer is reduced and removed, the surface of the conductor layer is still roughened. In the case of forming, there is a problem that voids are apt to remain at the bonding interface, not only the conduction resistance is increased, but also the disconnection due to a heat cycle is easily generated.

The method (3) is a method in which the conductor layer and the insulating layer are firmly bonded to each other via the composite plating layer on the surface of the conductor layer. However, the composite plating layer formed on the surface of the conductor layer has conduction resistance. Therefore, when a multilayer printed wiring board is to be manufactured using via holes, there is a disadvantage that the connection reliability of the via holes is low.

For this reason, each prior art is an effective method for a multilayer printed wiring board having no via hole or manufactured by a non-build-up method. However, when a multilayer printed wiring board having via holes is manufactured by a build-up method, there are many disadvantages as described above, and it has been difficult to apply the method.

As described above, when a multilayer printed wiring board having via holes is manufactured by a build-up method, a method for simultaneously obtaining excellent adhesive strength between a conductor layer and an insulating layer, and via hole connection reliability. Was not previously proposed.

However, the multilayer printed wiring board built up by the via hole can be formed at an arbitrary position by the interlayer connection by the via hole, so that the density can be increased, and its practical use has been strongly desired.

[Means for solving the problem]

The inventors of the present invention have conducted intensive studies and, as a result, have developed a multilayer printed wiring board having the following gist structure and a method for manufacturing the same, which can sufficiently satisfy the above-mentioned demands. That is, the present invention relates to a multilayer printed wiring board of a type in which an inner layer circuit composed of two or more conductor layers insulated by a heat-resistant resin layer is electrically connected mainly through via holes, Of the conductor layer having a roughened surface formed as described above, at least a part of a portion electrically connected to a subsequent conductor layer via a via hole has a glossy surface by a smoothing process, and the via The hole is provided by forming an opening in the heat-resistant resin layer, forming a roughened surface on the surface of the heat-resistant resin layer, and then forming a subsequent conductor layer. And a method for manufacturing a multilayer printed wiring board in which an inner layer circuit composed of two or more conductor layers insulated by a thermal resin layer is electrically connected mainly through via holes. When the surface of the previously formed conductor layer is roughened, and then electrically connected to the conductor layer formed later through via holes, at least a part of the surface of the previously roughened preceding conductor layer, A glossy surface is formed by a smoothing process, while the via hole is provided with an opening in the heat-resistant resin layer, a roughened surface is formed on the surface of the heat-resistant resin layer, and then a subsequent conductor layer is formed. And a method for manufacturing a multilayer printed wiring board.

In the above-mentioned production, soft etching or sand blasting is performed as the smoothing treatment for obtaining a glossy surface, and the roughening treatment applied to the preceding conductor layer oxidizes the surface of the conductor layer. This is performed by a post-reduction process.

(Operation)

The multilayer printed wiring board of the present invention has at least two conductive layers electrically insulated by a heat-resistant resin insulating layer, and each conductive layer is electrically connected by a via hole. It is configured as follows.

That is, the surface of the preceding conductor layer formed first of the conductor layers is first subjected to a roughening treatment in order to improve the adhesion with the insulating layer. At least a part of a portion electrically connected to a later-formed conductor layer formed later through the via hole has been subjected to a smoothing process for eliminating a roughened surface so as to exhibit a glossy surface. It has become.

The reason why the surface of the preceding conductor layer is provided with a glossy surface on a part thereof based on the roughened surface is as follows. That is, if the surface of the conductor layer is roughened first,
Basically, an anchoring effect occurs, and as a result, the adhesion between the conductor layer and the heat-resistant resin insulating layer formed on the conductor layer is improved. However, on the other hand, the connection performance is electrically degraded due to the via hole in relation to the subsequent conductor layer formed later. Therefore, by performing a smoothing process on at least a part of this part,
The purpose is to remove the connection surface whose shape has changed due to the roughening treatment or the surface where the chemical change has occurred. As a result, if the subsequent conductor layer formed later is electrically connected to the surface smoothed in this way, the connection reliability of the via hole, which is observed only in the case of the roughened surface alone, is reduced. Can be minimized.

Furthermore, in the present invention, the insulating layer made of a heat-resistant resin
Since the surface including the inner wall surface of the opening provided in the insulating layer is a roughened surface, the roughened surface improves the adhesion with the via hole provided in the opening. As a result, the via hole in contact with the preceding conductor layer and this conductor layer is both tightly integrated with the insulating layer made of the heat-resistant resin, so that even when a glossy surface is provided to ensure connection reliability, , Can be prevented from being separated from each other.

Examples of the above-described roughening treatment of the conductor layer surface include an oxidation treatment and an electrolytic treatment. Among them, a method of performing a reduction treatment after oxidizing the surface of the conductor layer is preferable.
The oxidation and reduction treatments are performed when electroless plating is performed.
A phenomenon in which copper oxide is dissolved in an aqueous solution of acidic palladium-tin hydrochloride for imparting catalytic properties, that is, a halo phenomenon can be prevented, and is a preferable roughening method in the present invention.

The area of the glossy surface subjected to the smoothing process is not limited to the area of the via hole, and may be larger or smaller than the area of the via hole. Also, the size of the via hole does not need to be restricted by the line width of the conductor pattern.

On the other hand, it is desirable that most of the portion where the via hole is not formed be roughened.

In the present invention, the heat-resistant resin forming the insulating layer is at least one selected from an epoxy resin, a polyimide resin, an epoxy acrylate resin, a urethane acrylate resin, a polyester resin, a bismaleimide / triazine resin, a phenol resin, and an epoxy-modified polyimide resin. Desirably a seed.

In addition, when performing electroless plating, a resin containing a filler capable of forming a concave portion that can serve as an anchor for electroless plating, that is, a heat-resistant resin that is hardly soluble in an oxidizing agent, contains “an average particle diameter of 2 to 10 μm. Mixture of heat-resistant resin particles and heat-resistant resin fine powder having an average particle size of 2 μm or less ”or“ average particle size of 2 to 2 μm ”.
"Pseudo particles obtained by adhering at least one of a heat-resistant resin fine powder having an average particle size of 2 μm or less and an inorganic fine powder having an average particle size of 2 μm or less” to the surface of heat-resistant resin particles having a particle size of 10 μm or less, Agglomerated particles obtained by aggregating a heat-resistant resin fine powder having a diameter of 2 μm or less into particles having an average particle diameter of 2 to 10 μm ”; It is desirable that the particles contain conductive particles. It is preferable to use a photosensitive resin as the heat-resistant hardly-soluble resin and an epoxy resin as the heat-resistant resin particles. By treating the resin containing the filler with an oxidizing agent such as chromate, chromate, permanganate, or ozone, a concave portion can be formed due to a difference in solubility in the oxidant.

Next, a method for manufacturing a multilayer printed wiring board according to the present invention will be described.

In the present invention, the surface of the preceding conductor layer forming the inner layer circuit is first roughened, and then at least a part of the preceding conductor layer electrically connected to the subsequent conductor layer formed later through the via hole. Needs to be smoothed.

Examples of such a roughening treatment include an oxidation treatment and an electrolytic treatment, and a method of performing a reduction treatment after performing the oxidation treatment is preferable.

In the method of performing the reduction treatment after the oxidation treatment, the oxidation treatment is performed using at least one solution selected from an aqueous solution of alkaline sodium chlorite, an aqueous solution of alkaline potassium persulfate, and an aqueous solution of potassium sulfide-ammonium chloride. Is preferred.

In addition, the reduction treatment is performed using formalin, hypophosphorous acid, sodium hypophosphite, hydrazine hydrate, hydrazine hydrochloride, hydrazine sulfate, sodium borohydride, N, N ′
-It is desirable to use at least one solution selected from trimethylborazane and the like.

In the method of performing a reduction treatment after oxidation, the oxidation treatment or the reduction treatment can be performed by applying, dipping, or spraying an oxidizing agent or a reducing agent on a portion to be treated.

The smoothing process in the present invention is desirably soft etching or sandblasting. The soft etching includes “a mixed solution of cupric chloride / hydrochloric acid / cuprous chloride”, “a mixed solution of ferrous chloride / ferric chloride / cupric chloride / cuprous chloride”, and “persulfuric acid. Saline solution ",
Using at least one kind of solution selected from "hydrogen peroxide / sulfuric acid mixed solution", "copper ammonium complex salt alkaline solution", etc., apply these soft etching solutions to the smoothed portion, or apply a soft etching solution to the wiring board. Or by spraying a soft etching solution to smooth the surface.

In addition, sandblasting is performed by spraying an inorganic fine powder mainly composed of at least one selected from silicon carbide, alumina, silicon dioxide and the like, together with a dispersion medium such as water. The diameter of the inorganic fine powder is 20 μm
It is desirable that:

The smoothing may be performed before the formation of the insulating layer, or may be performed after the formation of the insulating layer and the opening of the via hole. In the case where the smoothing is performed before forming the insulating layer, a mask may be applied to a non-smoothed portion, and then the smoothing process may be performed, or the soft etching solution may be applied to a portion to be smoothed. .

The method for forming the heat-resistant resin insulating layer is formed by applying an uncured solution of the heat-resistant resin, or by adhering a semi-cured film of the heat-resistant resin, and then performing a curing treatment. Preferably, the surface of the heat-resistant resin insulating layer may be roughened or coated with a coupling agent in order to improve the adhesion with a conductor layer to be formed later.

As the coating method, a method such as a roller coating method, a dip coating method, a spray coating method, a spinner coating method, a curtain coating method, and a screen printing method can be applied.

The opening for providing the via hole may be formed by exposing and developing a photosensitive resin, or a resin film having an opening formed in advance at the position where the via hole is provided may be adhered, It may be formed by processing.

The insulating layer made of the heat-resistant resin thus opened has a roughened surface as shown in the examples.

The subsequent conductor layer that is electrically connected to the conductor layer formed beforehand through the via hole can be formed by electrolytic plating, electroless plating, vapor deposition, or sputtering. Electroless plating is particularly preferable.

As the electroless plating, at least one of electroless copper plating, electroless gold plating, electroless silver plating, electroless tin plating, and electroless nickel plating can be used.

In order to improve the adhesion between the conductor layer and the heat-resistant resin insulation layer, a coupling agent may be applied to the surface of the conductor layer.

As the substrate used in the present invention, a plastic substrate, a glass epoxy substrate, a glass polyimide substrate, an alumina substrate, an aluminum nitride substrate, an aluminum substrate, an iron substrate, a polyimide film substrate, or the like can be used.

In the present invention, a conductive circuit can be formed by a known method performed on a printed wiring board, for example, when a circuit is etched after applying electroless plating to a substrate or when applying electroless plating. A method of directly forming a circuit or the like may be applied.

Example 1 (1) Glass epoxy copper-clad laminate (manufactured by Toshiba Chemical
A photosensitive dry film (manufactured by DuPont, trade name: Liston 1051) was laminated on a trade name: Toshiba Tecolite MEL-4), and the image was printed by ultraviolet exposure through a mask film on which a desired conductive circuit pattern was drawn. Then, development was performed with 1-1-1-trichloroethane, and copper in the non-conductor portion was removed using a cupric chloride etching solution.
The dry film was peeled off with methylene chloride. As a result, a wiring board having the first-layer conductor circuit 1 including a plurality of conductor patterns on the substrate 2 was formed. (Fig. 1a) (2) Epoxy resin particles (Toray's Trepal EP-
B, average particle size of 3.9 μm) 200 g of epoxy resin particles were dispersed in 5 parts of acetone in an epoxy resin particle suspension and stirred with a Henschel mixer (Mitsui Miike Kakoki Co., Ltd., Model FM10B). A suspension prepared by dispersing 300 g of an epoxy resin powder (Toray, Trepal EP-B, average particle size 0.5 μm) in an acetone solution containing 30 g of a resin (trade name, TA-1800, manufactured by Mitsui Petrochemical) After dropping the suspension, the epoxy resin powder was adhered to the surface of the epoxy resin particles, and then the acetone was removed.
Heating to 0 ° C. produced pseudo particles. The pseudo particles had an average particle size of about 4.3 μm, and about 75% by weight was in a range of ± 2 μm around the average particle size.

(3) 60% by weight of 50% acrylate of cresol novolak type epoxy resin (made by Yuka Shell, trade name: Epikote 180S) and 50% of bisphenol A type epoxy resin (made by Yuka Shell, trade name: Epikote 180S) 60 parts by weight of an acrylate, 40 parts by weight of a bisphenol A type epoxy resin (manufactured by Yuka Shell, trade name: Epicoat 1001), 15 parts by weight of diallyl terephthalate, 2-methyl-1- [4-
(Methylthio) phenyl] -2-morpholinopropanone-1 (Ciba Geigy, trade name: Irgacure 90
7) 4 parts by weight, imidazole (Shikoku Chemicals, trade name: 2P
After mixing 4 parts by weight of 4MHZ) and 50 parts by weight of the pseudo particles prepared in the above (2), the viscosity was adjusted to 250 cp with a homodisper stirrer while adding butyl cellosolve, and then 3 parts by weight.
The mixture was kneaded with this roller to prepare a solution of the photosensitive resin composition.

(4) An alkaline sodium chlorite solution was prepared by dissolving 60 g of sodium chlorite, 18 g of sodium hydroxide, 5 g of sodium phosphate, and 5 g of sodium carbonate in water to obtain 1.

(5) A 30% by weight aqueous solution of formalin (30 ml) and 38 g of KOH were dissolved in water 1 to prepare an alkaline reducing agent aqueous solution.

(6) The wiring board prepared in (1) and having the conductor pattern 1 having a line width of 100 μm was immersed in the alkaline sodium chlorite solution obtained in the step (4) for 2 to 3 minutes. Then, it was immersed in the aqueous alkaline reducing agent solution prepared in the above step (5) at 70 ° C. for 15 minutes to form a roughened surface 3 on the surface of the conductor pattern (FIG. 1B).

(7) The solution of the photosensitive resin composition prepared in the step (3) is applied by using a knife coater, and is applied in a horizontal state.
After standing for a minute, it was dried at 70 ° C. to form a photosensitive resin insulating layer having a thickness of about 50 μm.

(8) The printed circuit board subjected to the processing of the step (7) is
A photomask film on which a black circle of μmφ was printed was brought into close contact with the photomask film, and exposed at 500 mJ / cm ² using an ultra-high pressure mercury lamp. This was subjected to an ultrasonic development treatment with a chlorocene solution to form an opening 10 serving as a 100 μmφ via hole on the wiring board. Exposure of the wiring board to about 3000 mJ / cm ² with an ultra-high pressure mercury lamp, and heat treatment at 100 ° C. for 1 hour and then at 150 ° C. for 10 hours. A conductive resin insulating layer 4 was formed.

(9) Next, the wiring board is immersed in an oxidizing agent composed of 500 g of chromic acid / water solution at 70 ° C. for 15 minutes to form a heat-resistant resin insulating layer
After forming a roughened surface 5 on the surface of the sample, the sample was immersed in a neutralizing solution (PN-950, manufactured by Shipley) and washed with water (FIG. 1c).

(10) The wiring board that has been subjected to the process (9) is reduced by 6%
Of sulfuric acid and 10% hydrogen peroxide for 3 minutes to perform soft etching to form a smooth surface 6 on the conductor pattern (FIG. 1d).

(11) The surface of the resin insulating layer 4 is activated by applying a palladium catalyst (Cataposit 44, manufactured by Shipley Co., Ltd.) to the substrate 2 on which the heat-resistant resin insulating layer 4 has been roughened. The electroless copper plating solution 7 was immersed in the electroless copper plating solution for 11 hours to give a plating film 7 having a thickness of 25 μm (FIG. 1e).

(12) After repeating each of the above steps (1) to (11) twice, and further performing the above step (1), a build-up multilayer wiring board having four wiring layers (FIG. 1) (F) is prepared.

Example 2 (1) Epoxy resin particles (manufactured by Toray, Trepal EP-
B, average particle size 0.5 μm) is charged into a hot air dryer and
For 3 hours for coagulation bonding. The cohesively bonded epoxy resin particles were dispersed in acetone, crushed in a ball mill for 5 hours, and then classified using an air classifier to prepare coagulated particles. The agglomerated particles have an average particle size of about
3.5 μm, and about 68% by weight ±
It was in the range of 2 μm.

(2) 50 parts by weight of 75% acrylate of cresol novolak type epoxy resin (manufactured by Nippon Kayaku, trade name: EOCN-103S), 50 parts by weight of bisphenol A type epoxy resin (manufactured by Dow Chemical, trade name: DER661), 25 parts by weight of dipentaerythritol hexaacrylate, benzyl alkyl ketal (Ciba Geigy, trade name: Irgacure 65
1) 5 parts by weight, imidazole (Shikoku Chemicals, trade name: 2P4M
HZ) 6 parts by weight and 50 parts by weight of the aggregated particles prepared in the above step (1) are mixed, and while adding butyl cellosolve, the mixture is adjusted to a viscosity of 250 cp with a homodisper stirrer and kneaded with three rollers. Thus, a solution of the photosensitive resin composition was prepared.

(3) Line width obtained in step (1) of Example 1
A substrate 2 (FIG. 2a) having a conductor pattern 1 having a thickness of 100 μm was subjected to the processes (4) to (6) of the first embodiment to form a roughened surface 3 on the conductor pattern 1. (FIG. 2b) Then, the solution of the photosensitive resin composition prepared in the step (2) was applied using a knife coater, left in a horizontal state for 20 minutes, and dried at 70 ° C. A photosensitive resin insulating layer having a thickness of about 50 μm was formed (FIG. 2c).

(4) Example 1 was added to the wiring board obtained in the step (3).
The same operation as in the step (8) is performed to form the heat-resistant resin insulating layer 4 having the via hole 10 with a diameter of 50 μm, and the treatment of the step (9) in the first embodiment is performed. After forming the roughened surface 5 on the surface, inorganic particles having a diameter of 10 to 20 μm (manufactured by Nissan Chemical Industries; Snowtex ST-30, particle size 10 to
20 μm) was dispersed in water and sprayed from a nozzle 14 onto a wiring board, whereby the surface exposed by the opening 10 was polished to form a smooth surface 6 (FIG. 2d).

(5) The electroless copper plating film 7 was formed by performing the step (11) of the first embodiment (FIG. 2e).

(6) By repeating the above (1) to (5) two more times and then performing the step (1) of the first embodiment, a build-up multilayer wiring board having four wiring layers (FIG. 2f) It was created.

Example 3 (1) 100 parts by weight of a 50% acrylate of a phenol aralkyl type epoxy resin, 15 parts by weight of diallyl terephthalate, 2-methyl-1- [4- (methylthio) phenyl]
4 parts by weight of 2-morpholinoppanone-1 (manufactured by Ciba-Geigy, trade name: 2P4MHZ), 10 parts by weight of epoxy resin powder having a large particle diameter (manufactured by Toray, Trepearl EP-B, average particle diameter of 3.9 μm), and particles Epoxy resin powder with small diameter (manufactured by Toray,
Tolpearl EP-B, average particle size 0.5 μm) To 25 parts by weight of butyl carbitol was added, the viscosity was adjusted to 250 cp with a homodisper disperser, and then kneaded with three rollers to obtain a photosensitive resin composition. A solution was made.

(2) Line width obtained in the first step (1) of the first embodiment
Wiring board having conductor pattern 1 of 100 μm (FIG. 3a)
Then, the roughened surface 3 is formed by performing the processes of the steps (4) to (6) of Example 1 and a photosensitive dry film (manufactured by DuPont, trade name: Linston 1051) is formed on the obtained wiring board. Were laminated, and a mask film having a black circle printed thereon was adhered to a position where a via hole was to be formed, and was exposed to ultraviolet light. Then, development was performed using chlorocene to form a resist 10 for soft etching (FIG. 3b), and then the operation of (10) of Example 1 was performed to form a smooth surface 6 by etching (FIG. 3). c).

Table 2 shows the conditions of this example with respect to the line width, the diameter of the via hole, and the diameter of the black circle of the mask film.

The solution of the photosensitive resin composition prepared in the above (1) was applied using a knife coater, left in a horizontal state for 20 minutes, and then dried at 70 ° C. to form a photosensitive resin insulating layer having a thickness of about 50 μm. Formed.

(3) Example 1 was added to the wiring board obtained in the step (2).
Steps (8) and (9) are performed to form a roughened surface 5 on the surface of the heat-resistant resin insulating layer 4, and then the process (11) of Example 1 (FIG. 3d) Was carried out to give an electroless copper plating film 7 (FIG. 3e).

(4) The steps (1) to (3) are further repeated twice, and then the step (1) of Example 1 is performed, whereby a build-up multilayer wiring board having four wiring layers (3-1)
Figure (f)) was created.

Schematic diagrams of via holes obtained under the conditions of Nos. 2 to 7 described in Table 2 are shown in FIGS. 3-2 to 3-7 of the drawings.

Example 4 (1) Phenol novolak type epoxy resin (manufactured by Yuka Shell, trade name: 60 parts by weight, bisphenol A type epoxy resin (manufactured by Yuka Shell: E-1001) 40 parts by weight, imidazole curing agent (manufactured by Shikoku Chemicals) 4 parts by weight of 2P4MHZ), 25 parts by weight of an epoxy resin powder having a large particle size (trade name: Trepal EP-B, average particle size 0.5 μm, manufactured by Toray), butyl carbitol was added, and homodisper was added. The viscosity is adjusted to 250 cp with a disperser, and then kneaded with three rollers,
An adhesive solution was made.

(2) Next, the surface copper foil of the ceramic double-sided copper-clad laminate was photo-etched by a conventional method to obtain a wiring board having a conductor pattern 1 with a line width of 50 μm (FIG. 4a).

(3) Next, the wiring board was immersed in the solution obtained in step (4) of Example 1 for 2 to 3 minutes to form a roughened surface 3 on the surface of the conductor pattern 1 (fourth).
Figure b).

(4) The adhesive solution obtained in the step (1) was applied to the front surface by a roll coater, and then dried and cured at 100 ° C. for 1 hour and at 150 ° C. for 5 hours to form a heat-resistant resin insulating layer 4.

(5) CO ₂ laser 11 is used to form via holes
Is applied to the heat-resistant resin insulating layer 4 to form an opening 10
Was formed.

(6) Then, the surface was immersed in chromic acid for 10 minutes to form a roughened surface 5 on the surface of the heat-resistant resin insulating layer 4, and washed after neutralization.

(7) Then, by performing the operation described in step (10) of Example 1, soft etching was performed,
The smooth surface 6 was formed on the conductor pattern exposed through the opening 10 (FIG. 4d).

(8) Through holes 16 were formed by a conventional method.

(9) The surface of the heat-resistant resin insulating layer 4 was activated by applying a palladium catalyst (Cataposit 44, manufactured by Zipray Co., Ltd.) to the substrate 2.

(10) Next, a photosensitive dry film (manufactured by San Nopco, trade name: DFR-40C) was laminated on the wiring board, and the conductor pattern was exposed to light and then developed to form a plating resist 15.

(11) A build-up multilayer printed wiring board having a 25 μm-thick electroless copper plating film 7 formed at a position other than the plating resist by immersing in an electroless copper plating solution shown in Table 1 for 11 hours (fourth) (E) of the figure was produced.

Example 5 (1) After performing the step (1) of Example 1, electrolytic copper plating is performed while changing the current density, and the surface of the conductive pattern is subjected to non-uniform copper plating to form a roughened surface 3. Then, beforehand, a diameter of 15
A polyimide adhesive film 12 in which an opening 10 of 0 μm was formed and a polyimide film 13 were laminated in order from the side closer to the wiring board, and were bonded by heating and pressing at 275 ° C. and 45 kg / cm ² for 30 minutes.

(2) A smooth surface 6 is formed on the conductor pattern 1 exposed by the opening by performing the process of the step (10) of the first embodiment.
Was formed.

(3) A copper film 7 was formed by sputtering.

(4) After repeating the steps (1) to (3) two more times, the step (1) of Example 1 is performed once to obtain 4
A layered build-up multilayer printed wiring board was manufactured. FIG. 5 is a schematic view of a via hole portion of the build-up multilayer printed wiring board.

The adhesion strength between the heat-resistant resin insulating layer and the plating film of the multilayer printed wiring board thus manufactured was measured by the method of JIS-C-6481, and the results are shown in Table 3.

(Effects of the Invention) As described above, according to the multilayer printed wiring board and the method for manufacturing the same of the present invention, the adhesion between the conductor pattern and the heat-resistant resin insulating layer is extremely excellent, and the connection reliability of the via hole is improved. An excellent build-up multilayer printed wiring board can be provided, and the effect of contributing to industry is extremely large.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 (a) to 1 (f) are views showing steps of manufacturing a build-up multilayer printed wiring board of Example 1, respectively. FIGS. 2 (a) to 2 (f) are FIGS. 3A to 3F are diagrams respectively showing the manufacturing steps of the build-up multilayer printed wiring board according to the second embodiment; FIGS. FIGS. 3-2 to 3-7 are Nos. 2 to 3 of Example 3, respectively.
7 is a schematic view of a via-hole portion of a build-up multilayer printed wiring board of No. 7, (a) to (e) of FIG. 4 are diagrams showing manufacturing steps of the build-up multilayer printed wiring board of Example 4, respectively. Is a schematic diagram of a via hole portion of a build-up multilayer printed wiring board of Example 5, and FIG. 6 is a schematic diagram of a typical via hole. DESCRIPTION OF SYMBOLS 1 ... Conductor pattern (1st layer), 2 ... Substrate 3 ... Roughened surface of conductive pattern 4, ... Interlayer insulating layer, 5 ... Roughened surface of interlayer insulating layer 6 ... Smooth surface of conductive pattern 7 Copper plating film (second layer) 8 Conductor pattern (third layer) 9 Conductor pattern (fourth layer) 10 Resist for soft etching 11 Carbon dioxide laser 12 Polyimide adhesive film 13: Polyimide film 14: Nozzle for sandblasting 15: Resist for electroless plating

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-47-44066 (JP, A) JP-A-3-16196 (JP, A) JP-B-64-8479 (JP, B2) (58) Field (Int.Cl. ⁶ , DB name) H05K 3/46

Claims (6)

(57) [Claims] 1. A multilayer printed wiring board of a type in which an inner layer circuit composed of two or more conductor layers insulated by a heat-resistant resin layer is electrically connected mainly through via holes, wherein the inner layer circuit precedes the inner layer circuit. Based on the roughened surface, at least a part of the conductor layer electrically connected to the subsequent conductor layer via the via hole is made glossy by the smoothing process. The via hole is provided by forming an opening in the heat-resistant resin layer, forming a roughened surface on the surface of the heat-resistant resin layer, and then forming a subsequent conductor layer. A multilayer printed wiring board characterized by the following. 2. The multilayer according to claim 1, wherein the heat-resistant resin comprises heat-resistant resin hardly soluble in an oxidizing agent and heat-resistant resin particles soluble in the oxidizing agent. Printed wiring board. 3. A method of manufacturing a multilayer printed wiring board of a type in which an inner layer circuit composed of two or more conductor layers insulated by a heat-resistant resin layer is electrically connected mainly through via holes. When the surface of the previously formed conductor layer is roughened, and then electrically connected to the conductor layer formed later through via holes, at least a part of the surface of the previously roughened conductor layer On the other hand, a glossy surface is formed by a smoothing treatment.On the other hand, the via hole is provided with an opening in the heat-resistant resin layer, and a roughened surface is formed on the surface of the heat-resistant resin layer, and then the subsequent conductor layer is formed. A method for manufacturing a multilayer printed wiring board, characterized by being formed and provided. 4. The multilayer according to claim 3, wherein the heat-resistant resin comprises heat-resistant resin hardly soluble in an oxidizing agent and heat-resistant resin particles soluble in the oxidizing agent. Manufacturing method of printed wiring board. 5. The method for manufacturing a multilayer printed wiring board according to claim 3, wherein the smoothing process for obtaining a glossy surface is performed by soft etching or sandblasting. 6. The method for manufacturing a multilayer printed wiring board according to claim 3, wherein the roughening treatment performed on the preceding conductor layer is a treatment of oxidizing and reducing the surface of the conductor layer.