JP2000138452A - Manufacture of multilayered printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent noise of signals by premodifying the substrate-side surface of a resin insulating film by one or more methods selected from among plasma treatment, corona discharge treatment, or ultraviolet-light irradiation treatment. SOLUTION: It is necessary to treat the surface of a resin insulating film by plasma treatment, corona discharge treatment, ultraviolet-ray irradiation treatment, or a combination of these treatment. When the surface is treated, a polar group, such as the hydroxide group, carbonyl group, etc., is introduced to the surface of the resin and the adhesiveness of the surface with a metal is improved. Consequently, the adhesiveness of a conductor circuit on a substrate with a resin insulating layer 12 can be improved even when the surface of the circuit is not roughened. Therefore, the surface roughening of the conductor circuit is not required and no noise is produced even when the circuit is made to propagate high-frequency signals. When the surface of the resin insulating film is subjected to the plasma treatment, the surface is modified, because gas ions are attracted to the film and strike the surface of the resin or react to surface molecules.

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 using a resin substrate on which a conductive circuit is formed, and more particularly to a multilayer printed wiring board having excellent adhesion between a resin insulating layer and a conductive circuit and excellent signal propagation in a high frequency band. This is a proposal for a printed wiring board.

[0002]

2. Description of the Related Art As the frequency of signals increases, the package substrate is required to have a low dielectric constant and a low dielectric loss tangent, and the mainstream of the substrate material is shifting from ceramic to resin.

[0003] Against this background, Japanese Patent Laid-Open Publication No.
As disclosed in Japanese Patent No. 53, there has been proposed a technique of forming a conductive circuit by forming an interlayer resin insulating layer into a film, pressing the film onto a circuit board, roughening the surface with chromic acid, and plating the surface.

[0004]

However, when such a resin insulating film is used, it is necessary to roughen the surface of the conductive circuit of the substrate. Therefore, when a high-frequency signal is propagated, the signal propagates only through the surface portion of the roughened conductor circuit due to the skin effect, and noise is generated in the signal due to unevenness of the surface. is there. This problem was particularly remarkable when a resin substrate having a lower dielectric constant and a lower dielectric loss tangent than a ceramic substrate was used.

Accordingly, the present invention has been made to solve the above-described problems of the resin substrate, and a main object thereof is to prevent signal noise.

[0006]

Means for Solving the Problems The inventors of the present invention have intensively studied for realizing the above-mentioned object, and as a result, have arrived at an invention having the following content as a gist configuration. That is, the present invention provides a multilayer printed wiring board in which a resin insulating layer is provided by laminating a resin insulating film on a resin substrate on which a conductive circuit is formed, and is heated and pressed to form a conductive circuit on the resin insulating layer. Wherein the side surface of the substrate of the resin insulating film is modified in advance by at least one method selected from plasma treatment, corona discharge treatment and ultraviolet irradiation treatment.

In the present invention, it is necessary to treat the surface of the resin insulating film by plasma treatment, corona discharge, ultraviolet irradiation treatment or a combination thereof. By performing a plasma treatment, a corona discharge treatment, or an ultraviolet irradiation treatment, a polar group such as a hydroxyl group or a carbonyl group is introduced into the resin surface, and the adhesion to a metal is improved. For this reason, the adhesion with the resin insulating layer can be improved without roughening the surface of the conductive circuit on the substrate. Therefore, there is no need to roughen the surface of the conductor circuit, and no noise is generated even when a high-frequency signal is propagated. As the plasma treatment, reverse sputtering, oxygen plasma, CF ₄ gas plasma, or the like is used. Reverse sputtering refers to a process in which a sputtering process is performed using a target material as an anode and a resin insulating film as a cathode, contrary to a normal sputtering process.

[0008] In the plasma treatment, gas ions are attracted to the resin insulating film, and the surface is modified by hitting the resin surface or reacting with surface molecules. As a gas used in the plasma treatment, for example, an inert gas such as argon, neon, helium, krypton, or nitrogen, or a reactive gas such as oxygen or CF ₄ is used. The pressure for performing the plasma treatment is 0.1 to 1.0 Pa · s.
Is preferred. The processing time is preferably 0.5 to 5 minutes. The temperature of the treatment is preferably 50 to 100 ° C. Corona discharge is a process in which an electric field is applied between a resin insulating film and an electrode, and the surface is modified by discharge generated by dielectric breakdown. The surface can also be modified by irradiating ultraviolet rays using a low-pressure mercury lamp. It is presumed that the bond in the molecular chain of the resin is broken by any of the treatments to generate a polar group.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for manufacturing a printed wiring board according to the present invention will be described with reference to a multilayer printed wiring board as an example. (1) First, a wiring board in which an inner layer copper pattern is formed on the surface of a resin substrate is manufactured. As the resin substrate, a resin substrate having inorganic fibers is desirable, and specifically, at least one or more selected from a glass cloth epoxy substrate, a glass cloth polyimide substrate, a glass cloth bismaleimide-triazine resin substrate, and a glass cloth fluororesin substrate Is good. The formation of the copper pattern on the resin substrate is performed by etching a copper-clad laminate having copper foil on both sides of the resin substrate.

In addition, a through hole is drilled in this substrate by a drill,
Electroless plating is applied to the wall surfaces of the through holes and the copper foil surface to form through holes. Copper plating is preferred as the electroless plating. In the case of a substrate such as a fluororesin substrate, which has poor coverage of plating, surface modification such as treatment with a pretreatment liquid (trade name: tetra-etch) made of organometallic sodium or plasma treatment is performed. Next, electrolytic plating is performed for thickening. Copper plating is preferable as the electrolytic plating. The inner wall of the through hole and the surface of the electrolytic plating film may be roughened. As roughening treatment, blackening (oxidation)
-Reduction treatment, spray treatment with a mixed aqueous solution of an organic acid and a cupric complex, or treatment with copper-nickel-phosphorus needle-like alloy plating. Alternatively, a conductive paste may be filled in the through holes as necessary, and a conductive layer covering the conductive paste may be formed by electroless plating or electrolytic plating.

(2) A resin insulating layer is formed on the wiring board manufactured in (1). This resin insulating layer functions as an interlayer resin insulating layer of the multilayer printed wiring board. As described above, the resin-insulating layer modifies the surface of the resin-insulating film on the substrate side by subjecting the surface of the resin-insulating film on the substrate side to plasma treatment, corona discharge treatment, ultraviolet treatment, or the like. Next, the resin insulating layer of the present invention is desirably made of a thermosetting resin, a thermoplastic resin, or a composite resin thereof. As the thermosetting resin, it is desirable to use at least one or more selected from thermosetting polyolefin resins, epoxy resins, polyimide resins, phenol resins, and bismaleimide toazine resins. As the thermoplastic resin, it is desirable to use engineering plastics such as polymethylpentene (PMP), polystyrene (PS), polyethersulfone (PES), polyphenylene ether (PPE), and polyphenylene sulfide (PPS).

Particularly, in the present invention, it is optimal to use a polyolefin resin as the resin insulating layer. The polyolefin-based resin is a resin having the following structure. . A resin comprising one type of repeating unit represented by the following structural formula.

Embedded image . A resin comprising a copolymer of two or more different repeating units represented by the following structural formula.

Embedded image . A resin having a repeating unit represented by the following structural formula and having a double bond, an oxide structure, a lactone structure, or a mono- or polycyclopentadiene structure in its molecular main chain.

Embedded image . A mixed resin obtained by mixing two or more resins selected from the group of the above, a mixed resin of a resin selected from the group of the above and the thermosetting resin, or
A resin obtained by crosslinking resins selected from the group consisting of: In the present invention, “resin” is a concept including so-called “polymer” and “oligomer”.

The resin (1) will be described in detail. The reason why the resin of the above-mentioned resin containing the structure of the repeating unit is adopted is that a thermosetting polyolefin can be obtained without lowering the fracture toughness value. Here, as the alkyl group used as X in the repeating unit, at least one selected from a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, and a t-butyl group is preferable. Examples of the C2-C3 unsaturated hydrocarbon employed as X in the repeating unit include CH ₂ ＣＨCH—, CH ₃ CH ＝ CH—, and C 2
At least one selected from H ₂ ＣC (CH ₃ ) — and an acetylene group is desirable. The oxide group employed as X in the repeating unit is preferably an epoxy group or a propoxy group, and the lactone group is at least one selected from a β-lactone group, a γ-lactone group, and a δ-lactone group. desirable.

Further, X in the repeating unit is C2 to C2.
The reason why the unsaturated hydrocarbon, oxide group, lactone group, and hydroxyl group of No. 3 are employed is that they have high reactivity and easily crosslink resins (in this case, oligomers) containing these functional groups. Further, the reason why n is set to 1 to 10,000 is that n is
If it exceeds 10,000, the solvent becomes insoluble and it becomes difficult to handle.

In the above resin, the double bond structure in the molecular main chain includes a repeating unit represented by the following structural formula,-(CH = CH)-or-(CH ₂ -CH = CH
It is preferable that a repeating unit of —CH ₂ ) — is copolymerized.

[0016]

Embedded image

In the above resin, the oxide structure of the molecular main chain is preferably an epoxy structure. As the lactone structure of the molecular main chain, β-lactone and γ-lactone structures are desirable. Further, as the mono- or polycyclopentadiene of the molecular main chain, a structure selected from cyclopentadiene and bicyclopentadiene can be adopted.

In the above copolymer, the repeating unit is ABAB.
..When alternating copolymerization as in the above, the repeating unit is AB
There are cases where random copolymerization such as AAABAAAAB... Or block copolymerization such as AAAAABBB.

Next, the following resin will be described. Is a mixed resin obtained by mixing two or more kinds of resins selected from the group of,,, or a mixed resin of a resin selected from the group of,, and a thermosetting resin, or the resin,,
Are resins cross-linked with each other.
When two or more resins selected from the above groups are mixed, the resin powder is dissolved in an organic solvent or is melted by heat and mixed. In addition, when a resin selected from the group described above and a thermosetting resin are mixed, the resin powder is dissolved in an organic solvent and mixed.
As the thermosetting resin to be mixed in this case, it is desirable to use at least one or more selected from thermosetting polyolefin resins, epoxy resins, phenol resins, polyimide resins, and bismaleimide triazine (BT) resins. Further, when the resins selected from the groups described above are crosslinked with each other, a C2 to C3 unsaturated hydrocarbon,
An oxide group, a lactone group, a hydroxyl group and a double bond in the molecular main chain, an oxide structure, and a lactone structure are used as bonds for crosslinking.

As a commercially available product of the thermosetting polyolefin resin used in the present invention, 1592 (trade name, manufactured by Sumitomo 3M Limited) can be mentioned. Commercially available thermoplastic polyolefin resins having a melting point of 200 ° C. or higher include TPX (trade name: 240 ° C.) manufactured by Mitsui Chemicals and SPS (melting point: 270 ° C.) manufactured by Idemitsu Petrochemical. TPX is a resin in which X in the repeating unit is an isobutyl group, and SPS is a resin in which X is a phenyl group and has a syndiotactic structure.

Since such a polyolefin resin has excellent adhesion to a conductor circuit, a conductor can be formed without roughening the surface of the resin insulating layer. That is, a conductive circuit can be formed on the surface of the flat resin insulating layer. Further, this polyolefin resin has a dielectric constant of 3 or less and a dielectric loss tangent of 0.05 or less, which is lower than that of the epoxy resin, and has no propagation delay even at a high frequency signal. In addition, polyolefin resin has heat resistance comparable to epoxy resin,
No peeling of the conductor circuit is observed even at the solder melting temperature. Furthermore, since the fracture toughness value is large, cracks starting from the boundary between the conductor circuit and the resin insulating layer due to the heat cycle do not occur. The resin insulating film is formed by hot-pressing and laminating the resin insulating film on a conductive circuit forming substrate.

(3) Next, the resin insulating layer is provided with an opening for ensuring electrical connection with a lower conductive circuit. The perforation of this opening is performed by laser light. At this time, a laser beam used includes a carbon dioxide gas laser, an ultraviolet laser, an excimer laser, and the like. If holes are formed by CO ₂ laser light, desmear processing is performed. Desmear treatment, chromic acid, it can be carried out using an oxidizing agent comprising an aqueous solution, such as permanganate, the oxygen plasma, mixed plasma or corona discharge of CF ₄ and oxygen, by treatment with an ultraviolet irradiation treatment Is also good. The surface can also be modified by irradiating ultraviolet rays using a low-pressure mercury lamp. In particular, a mixed plasma of CF ₄ and oxygen is advantageous because a hydrophilic group such as a hydroxyl group or a carbonyl group can be introduced to the resin surface, and the subsequent CVD or PVD treatment is easily performed.

(4) On the surface of the resin insulating layer provided with the opening in the above (3), at least one kind selected from metals of Groups 4a to 1b and fourth to seventh periods, Sn, Al, etc. Is formed by a plating method, a PVD method or a CVD method. Since such a metal has excellent adhesion to an insulating resin, the resin insulation layer can ensure adhesion to an upper conductive circuit without providing a roughened layer on the surface. Specific examples of the PVD method include vapor deposition methods such as sputtering and ion beam sputtering.
Further, as the CVD method, allylcyclopentadiphenylpalladium, dimethyl gold acetyl acetate,
Specific examples include PE-CVD (Plasma Enhanced CVD) using an organic metal (MO) such as tin tetramethylacrylonitrile or dicobalt octacarbonylacrylonitrile as a supply material. Further, a Cu layer may be provided on the above-described transition metal. The Cu layer can improve the adhesion of the conductor circuit to the transition metal when the conductor circuit formed thereon is copper.

In the printed wiring board of the present invention, at least one selected from metals (excluding Cu), Sn, and Al in the fourth to seventh periods in the 4a to 1b groups constituting the metal layer. Al, Fe,
At least one selected from W, Mo, Sn, Ni, Co, Cr, Ti and a noble metal is desirable. Pd, Au, and Pt are preferable as the noble metal.

The thickness of these metal layers is 0.02 μm to 0.2 μm.
m is desirable. The reason is that by setting the thickness to 0.02 μm or more, the adhesion between the resin insulating layer and the conductor circuit can be secured, and by setting the thickness to 0.2 μm or less, the stress when forming the metal layer by sputtering is reduced. This is because not only can cracks occurring as a cause be prevented be prevented, but also unnecessary metal layers between the conductor circuits after the formation of the conductor circuits can be easily removed by etching. In addition, Cu formed on the metal layer
The thickness of the layer is preferably from 0.02 μm to 0.2 μm. The reason for this is that by setting the thickness to 0.02 μm or more, the adhesion between the metal layer and the conductor circuit can be secured, and when the thickness is set to 0.2 μm or less, the stress when forming the metal layer by sputtering is caused. Not only can prevent cracks that occur due to the
This is because the u layer can be easily removed by etching.

It is desirable to provide another type of metal layer on the metal layer as needed. Specifically, by forming a nickel layer on the resin insulating layer and forming a copper layer on the nickel layer, it is possible to prevent non-precipitation of plating when forming a conductor circuit. The metal layer, electroless plating,
It is formed by a method such as electrolytic plating, sputtering, vapor deposition, or CVD.

(5) Next, on the metal layer formed in the above (4), a metal layer of the same type as the electroless plating film in the next step is formed by sputtering or the like. This is to improve the affinity with the electroless plating film. Specifically, it is desirable to provide a copper layer by sputtering.

(6) Next, electroless plating is performed on the metal layer formed in (5). Copper plating is most suitable as electroless plating. The thickness of the electroless plating is 0.1 to 5 μm.
m is good. The reason for this is to enable etching removal without impairing the function of the electroplating performed later as a conductive layer.

(7) A plating resist is formed on the electroless plating film formed in (6). This plating resist
It is formed by laminating a photosensitive dry film, exposing and developing.

(8) Next, electrolytic plating is performed using the electroless plating film as a plating lead to thicken the conductor circuit. The thickness of the electrolytic plating film is preferably 5 to 30 μm.

(9) Then, after the plating resist is removed, the electroless plating film under the plating resist and at least one selected from metals of Group 4a to Group 1b in the fourth to seventh periods, Sn, and Al. At least one kind of metal layer is removed by etching to form an independent conductor circuit. Examples of the etchant include sulfuric acid-hydrogen peroxide aqueous solution, ammonium persulfate, sodium persulfate, potassium persulfate aqueous solution, ferric chloride, cupric chloride aqueous solution, hydrochloric acid, nitric acid, hot dilute sulfuric acid and the like. Can be used.

(10) If necessary, at least one or more thin metal layers selected from metals of Groups 4a to 1b and of the fourth to seventh periods are formed on the surface of the conductor circuit by plating, PVD, or the like. Formed by the CVD method or the CVD method.
By repeating the steps (2) to (9), a multilayer printed wiring board is obtained.

In the above description, the semi-additive method is employed as a method of forming a conductor circuit, but a full-additive method may be employed. In this fully additive method, after forming a thin metal layer on the surface of the resin insulating layer by CVD or PVD processing, laminating a photosensitive dry film or applying a liquid photosensitive resin,
Exposure and development are performed to provide a plating resist, which is then thickened by electroless plating to form a conductor circuit.

Alternatively, after forming a plating resist on the surface of the resin insulating layer, a thin metal layer is provided by CVD or PVD treatment, and the metal layer adhered to the surface of the plating resist is removed by polishing or the like, or the plating resist itself is removed. Is removed, and electroless plating is performed using the metal layer as a catalyst to form a conductor circuit. Hereinafter, description will be made based on embodiments.

[0035]

[Electroless plating aqueous solution]

 EDTA 150 g / l Copper sulfate 20 g / l HCHO 30 ml / l NaOH 40 g / l α, α'-bipyridyl 80 mg / l PEG 0.1 g / l [Electroless plating conditions] 30 minutes at a liquid temperature of 70 ° C.

Further, electrolytic copper plating was performed with an electrolytic plating aqueous solution having the following composition under the following conditions to form an electrolytic copper plating film having a thickness of 15 μm (see FIG. 1 (c)). [Electroplating aqueous solution] Sulfuric acid 180 g / l Copper sulfate 80 g / l Additive (manufactured by Atotech Japan, trade name: Capparaside GL) 1 ml / l [Electroplating conditions] Current density 1 A / dm ² hours 30 minutes Temperature Room temperature

(2) The substrate on which the inner layer copper pattern (including the through holes 3) was formed was washed with water and dried, and then used as an oxidation bath (blackening bath) as NaOH (20 g / l), NaCl
An aqueous solution of O ₂ (50 g / l) and Na ₃ PO ₄ (15.0 g / l) was used, and NaOH (2.7 g / l), NaBH ₄ (1.0
g / l) of an aqueous solution of an aqueous solution (FIG. 1 (d)).
reference).

(3) The conductive paste 5 containing copper particles was filled in the through holes 3 by screen printing, dried and cured. Then, the conductive paste 5 protruding from the roughened layer 4 and the through holes 3 on the upper surface of the conductor is removed by belt sanding using # 400 belt abrasive paper (manufactured by Sankyo Rikagaku), and further, the scratches caused by the belt sanding are removed. The substrate surface was flattened by buffing to remove it (see FIG. 1 (e)).

(4) An electroless copper plating film 6 having a thickness of 0.6 μm is formed by applying a palladium colloid catalyst according to a conventional method on the substrate surface flattened in the above (3), and then performing electroless plating. (See FIG. 1 (f)).

(5) Next, electrolytic copper plating is performed under the following conditions to form an electrolytic copper plating film 7 having a thickness of 15 μm, a portion to be a conductor circuit 9 is thickened, and a conductive film filled in the through hole 3 is formed. Conductor layer (lid plating layer) 10 covering paste 5
Was formed. [Electroplating aqueous solution] Sulfuric acid 180 g / l Copper sulfate 80 g / l Additive (manufactured by Atotech Japan, trade name: Capparaside GL) 1 ml / l [Electroplating conditions] Current density 1 A / dm ² hours 30 minutes Temperature Room temperature

(6) A commercially available photosensitive dry film is adhered to both sides of the substrate on which the portions to be the conductor circuits 9 and the conductor layers 10 are formed, a mask is placed, and exposure is performed at 100 mJ / cm ² .
The resist was developed with 0.8% sodium bicarbonate to form an etching resist 8 having a thickness of 15 μm (see FIG. 2A).

(7) Then, the plating film in the portion where the etching resist 8 is not formed is dissolved and removed by etching using a mixed solution of sulfuric acid and hydrogen peroxide, and the plating resist 8 is stripped with 5% KOH. After removal, a conductor layer 10 (hereinafter, this conductor layer is simply referred to as a “lid plating layer”) 10 covering the independent conductor circuit 9 and the conductive paste 5 was formed (see FIG. 2B).

(8) Next, the surface of the substrate side of the thermosetting polyolefin resin sheet (manufactured by Sumitomo 3M, trade name: 1592) having a thickness of 50 μm was coated with SV-4540 manufactured by Nippon Vacuum Engineering Co., Ltd.
To perform a plasma treatment to provide a surface modified layer 11. Argon gas was used as the inert gas. The reverse sputtering was performed for 2 minutes under the conditions of power 200 W, gas pressure 0.6 Pa, and temperature 70 ° C. (Fig. 3 (a), (b)
reference)

(9) This thermosetting polyolefin resin sheet is laminated on both sides of the substrate by heating and pressing at a pressure of 10 kg / cm ² while the temperature is raised to a temperature of 50 to 180 ° C., and an interlayer resin insulation made of a polyolefin resin is formed. The layer 12 was provided (FIG. 3 (c),
(See FIG. 4 (a)).

(10) With a CO ₂ gas laser having a wavelength of 10.4 μm, the resin insulating layer 12 made of a polyolefin resin has a diameter of
An 80 μm via hole opening 13 was provided. Furthermore, CF
_The surface of the desmear and polyolefin-based resin insulation layer was modified by plasma treatment with a mixed gas of ₄ and oxygen (see FIG. 4 (b)). The oxygen plasma processing conditions are power 800 W, 500 mTorr, and 20 minutes.

(11) Sputtering using Ni as a target was performed under the conditions of a pressure of 0.6 Pa, a temperature of 80 ° C., a power of 200 W, and a time of 5 minutes to form a Ni thin film on the surface of the polyolefin resin insulating layer 12. At this time, the thickness of the formed Ni metal layer was 0.1 μm. Further, on the Ni metal layer, a copper layer having a thickness of 0.1 μm was formed by sputtering under the same conditions. The equipment for sputtering is
SV-4540 manufactured by Japan Vacuum Engineering Co., Ltd. was used.

(12) The substrate subjected to the treatment of (11) is subjected to the electroless plating of (1) to form an electroless plating film 14 having a thickness of 0.7 μm (FIG. 5A). reference).

(13) A commercially available photosensitive dry film is stuck on both sides of the substrate on which the electroless plating film 14 is formed in the above (12), a photomask film is placed, and exposure is performed at 100 mJ / cm ^2. Developed with 15% sodium carbonate
(See FIG. 5 (b)).

(14) Further, the electrolytic plating of (1) is performed to form an electrolytic plating film 15 having a thickness of 15 μm.
The portion was thickened and the via hole 17 was plated and filled (see FIG. 5 (c)).

(15) Further, the plating resist 16 is
% KOH, the Ni film under the plating resist 16 and the electroless plated film 14 are dissolved and removed by etching using a mixed solution of nitric acid and sulfuric acid / hydrogen peroxide.
A 16 μm-thick conductor circuit (including the via hole 17) composed of the film, the electroless copper plating film 14, and the electrolytic copper plating film 15 was formed (see FIG. 5D).

(Example 2) In this example, TPX (trade name) manufactured by Mitsui Chemicals was used as the polyolefin resin, and corona discharge was used instead of the plasma treatment. Further, in this embodiment, Pd is further set to an atmospheric pressure of 0.6 Pa, and a temperature of 0.6 Pa.
A multi-layer printed wiring board was manufactured in the same manner as in Example 1 except that the polyolefin-based resin insulating layer was attached at a thickness of 0.1 μm under the conditions of 100 ° C., power of 200 W, and time of 2 minutes.

Example 3 In this example, SPS (trade name) manufactured by Idemitsu Petrochemical Co., Ltd. was used as a polyolefin resin, and instead of plasma treatment, UV irradiation was performed by a low-pressure mercury lamp to perform surface modification. went. The irradiation dose is 3000mJ
Met. Further, Ti is supplied at a pressure of 0.6 Pa and a temperature of 100 Pa.
A multilayer printed wiring board was manufactured in the same manner as in Example 1, except that the polyolefin-based resin insulating layer was adhered at a thickness of 0.1 μm at a temperature of 200 ° C., a power of 200 W, and a time of 5 minutes.

(Comparative Example 1) (1) This comparative example is the same as Example 1, except that the surface of the polyolefin resin constituting the interlayer resin insulating layer on the substrate side is heated without any special treatment. Crimped. Steam tests were performed on the printed wiring boards obtained in Examples 1 to 3 and Comparative Example. The conditions were left at 120 ° C. and 2 atm for 336 hours. In Examples 1 to 3, although no separation was observed between the polyolefin resin insulating layer and the conductor circuit,
In the comparative example, peeling was observed.

[0054]

As described above, according to the printed wiring board of the present invention, the interface between the conductor circuit and the resin insulation layer is flattened without reducing the adhesion strength between the conductor circuit and the interlayer resin insulation layer. It is possible to provide a printed wiring board having excellent signal propagation properties in a high frequency band.

[Brief description of the drawings]

FIGS. 1A to 1F are views showing a part of a process of manufacturing a multilayer printed wiring board according to a first embodiment;

FIGS. 2A and 2B are diagrams illustrating a part of a process of manufacturing the multilayer printed wiring board of Example 1. FIGS.

FIGS. 3 (a), (b), and (c) are views showing a part of a process of manufacturing the multilayer printed wiring board of Example 1. FIG.

FIGS. 4A and 4B are diagrams illustrating a part of a process of manufacturing the multilayer printed wiring board according to the first embodiment;

FIGS. 5A to 5D are views showing a part of a process of manufacturing the multilayer printed wiring board according to the first embodiment;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Copper foil 3 Through hole 4 Roughening layer 5 Resin filler 6,14 Electroless plating film 7,15 Electrolytic plating film 8 Etching resist 9 Conductor circuit 10 Conductor layer (lid plating layer) 11 Surface modification layer 12 Interlayer Resin insulation layer 13 Via hole opening 16 Plating resist 17 Via hole

Continued on front page F term (reference) 5E346 AA05 AA06 AA12 AA15 AA32 AA43 BB02 CC08 DD02 DD22 DD33 DD47 EE02 EE06 EE08 EE19 EE31 EE33 EE38 FF03 FF12 FF17 GG02 GG15 GG17 GG22 GG27 H11H06

Claims (2)

[Claims] 1. A multilayer printed wiring board comprising: a resin insulating film provided on a resin substrate on which a conductive circuit is formed; and heating and pressing to form a resin insulating layer, and a conductive circuit formed on the resin insulating layer. A multilayer printed wiring board, characterized in that the surface of the resin insulating film that contacts the substrate is modified in advance by at least one method selected from plasma treatment, corona discharge treatment, and ultraviolet irradiation treatment. Manufacturing method. 2. The plasma processing includes reverse sputtering, oxygen plasma, CF ₄ plasma processing, oxygen and C
Method for manufacturing a multilayer printed wiring board according to claim 1 which is a mixed gas plasma treatment F _4.