JPH1187865A - Printed circuit board and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form more fine and accurate wiring layer by forming an easily roughing insulation resin layer to be easily roughed on an upper surface of heat resistant resin difficult to be roughed, thereby obtaining a sufficient adhesive strength between the wiring layer formed on the resin layer and the easily roughing insulation resin layer. SOLUTION: Coating layers 2 made of easily roughing epoxy insulation resin are formed on both upper and lower surfaces of an insulating board 1 made of BT(bismaleimide-triazine) resin-glass composite material. A wiring layer 9 made of a thin film layer 7 and an electrolytic copper plating layer 8 is formed on each of the layer 2 and an inner wall surface of a through hole, and has a continuity with one another via a wiring layer (conductor 10 in the through hole) in the hole. Thus, even in the case of using an insulation board made of resin difficult to be roughed like the BT resin, a fine wiring layer can be formed from its first layer, and an anchoring effect for raising adhesive properties of the wiring layer with the easily roughed resin layer is easily obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed wiring board manufactured mainly by a stacking method or a laminating method and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, the wiring density of printed wiring boards has been increased with the development of electronic devices. Many conventional printed wiring boards use copper-clad laminates that are made by integrating copper foil on an insulating substrate (core substrate) in which glass cloth is impregnated with a heat-resistant resin. Electroless plating is applied to the inner wall surface and the entire copper foil surface, and if necessary, further electrolytic plating is performed to obtain the required thickness for the wiring layer, and unnecessary parts are etched away to manufacture printed wiring boards. doing.

[0003]

However, since a glass cloth is used as a material for such an insulating substrate, there are slight irregularities due to the texture of the glass cloth on the surface. This unevenness has a width and a spacing of 100 μm of the wiring layer formed thereon.
Up to m, there was not much problem in processing accuracy, but as required today, both the width and the interval of the wiring layer are 60 μm.
In the case where a wiring layer having a thickness of m or less is formed, the formation of an etching resist cannot be performed accurately due to the unevenness. Also, the copper exposed from the etching resist is removed as the etching proceeds, but if there is this unevenness, the etching proceeds not only in the thickness direction of the insulating substrate but also in the direction of reducing the width of the wiring layer. As a result, the processing accuracy is reduced. Further, the thickness of the first wiring layer of the printed wiring board obtained by etching the copper foil has a thickness of approximately 28 to 30 μm in accordance with the thickness of the copper foil portion and the thickness of the plating layer thereon. It is not easy to accurately form a wiring layer of 100 μm or less by etching a copper foil.

The formation of a fine wiring layer having a wiring width of 100 μm or less by etching, which was difficult to realize with a conventional copper foil,
In some cases, this has become possible using copper foil with a microscopic, non-oriented crystal structure (Fujii: Copper foil for fine lines, electronic materials, Vol. 34, No. 10, p. 31 (1995)) However, since such a copper foil is difficult to obtain a mechanical anchoring effect, there is a problem in reliability that it is difficult to obtain an adhesion strength with a copper wiring layer using the copper foil.

In the method of forming a wiring layer by etching a copper foil, the thickness of the wiring layer obtained by adding the copper foil and plating is as large as about 30 μm, so that irregularities occur on the substrate surface as the insulating layer is stacked. There are also problems. If such irregularities are present on the substrate surface, it is disadvantageous in terms of chip mounting and the like, and the adherence of the plating resist to the dry film is deteriorated, so that there is a problem that the plating is dropped.

As a method of avoiding the unevenness, a method of filling a gap between wiring layers formed by etching with an insulating resin and correcting a step is disclosed in Japanese Patent Application Laid-Open No. 59-74608 and Japanese Patent No. 192414. However, there are many process problems, such as the problem of sagging or bleeding of the printed resin on the wiring layer that occurs when forming the resin by screen printing, and adding a process such as polishing to solve this . In order to eliminate such troubles, there is a method of forming a wiring layer by directly applying electroless plating or the like on an insulating substrate without using a copper foil. However, the material of the insulating substrate is BT (bismaleimide-triazine) resin. As described above, when the plating film is made of a material that is difficult to obtain a mechanical anchoring effect, there is a problem that the adhesion strength between the wiring layer and the insulating substrate thereunder cannot be sufficiently obtained.

According to these conventional techniques, it is difficult to process fine wiring of 100 μm or less by a conventional method of etching a copper-clad substrate, and it is easy to perform fine processing by etching, but it is difficult to obtain a mechanical anchoring effect. The method using a copper-foiled substrate with a fine and non-oriented crystal structure is inferior in the reliability of the adhesion of the wiring layer. In addition, the method using copper foil easily removes irregularities on the substrate surface due to the stacking of insulating layers. Is difficult to avoid. There is also a method of forming a circuit by directly applying electroless plating or the like on an insulating substrate without using a copper foil, but the material of the insulating substrate is BT (bismaleimide-based).
Triazine) When it is difficult to roughen like a resin, that is, when the plating film is a material that is difficult to obtain a mechanical anchoring effect,
There is a problem that the adhesion strength of the wiring layer is not obtained. Also,
Even if it is treated with an oxidizing agent to directly roughen the surface of an insulating substrate of another material, roughening that can provide an effective anchoring effect as easily as an insulating resin material whose components are adjusted on the premise of roughening There was a problem that the surface was difficult to form.

[0008] It is an object of the present invention to provide a printed wiring board and a method of manufacturing the printed wiring board which can solve a plurality of problems of these various methods at once.

[0009]

To achieve the above object, a printed wiring board according to the first aspect of the present invention comprises an insulating substrate made of a heat-resistant resin, which is difficult to roughen, and an insulating substrate formed on the insulating substrate. Further, it is characterized by having a roughening insulating resin layer made of a resin that is easier to roughen than the heat-resistant resin, and a wiring layer formed on the roughening insulating resin layer.

[0010] According to such a structure, since the easily roughened insulating resin layer is formed on the upper surface of the heat-resistant resin which is hardly roughened, the wiring layer formed on the easily formed roughened insulating resin layer has Sufficient adhesion strength can be obtained with the easily roughening insulating resin layer. Therefore, even if a heat-resistant resin that is difficult to roughen is used, a wiring layer can be formed thereon by a conventionally known semi-additive method, a full-additive method, a subtractive method, or the like. A finer and more accurate wiring layer having an interval of 100 μm or less, particularly 60 μm or less can be formed.

[0011] Next, the configuration of the printed wiring board according to the second aspect of the present invention comprises an insulating substrate made of a heat-resistant resin, which is difficult to roughen, a through hole formed in the insulating substrate, a surface of the insulating substrate, Formed on the inner wall surface of the through hole, an easily roughening insulating resin layer made of a resin that is easier to roughen than the heat resistant resin, and a wiring layer formed on the easily roughening insulating resin layer, It is characterized by having.

According to such a configuration, the easily roughening insulating resin layer is provided on the surface of the insulating substrate made of a heat-resistant resin which is difficult to roughen, and on the inner wall surface of the through hole formed in the insulating substrate. Therefore, a printed wiring board having good adhesion between the wiring layer and the easily roughening resin layer on the insulating substrate and in the through hole can be obtained. Therefore, even if an insulating substrate made of a heat-resistant resin that is difficult to roughen is used, a wiring layer can be formed on the upper surface or in the through hole by a conventionally known semi-additive method, full-additive method, subtractive method, or the like. ,
A finer and more accurate wiring layer can be formed.

As the insulating substrate (core substrate) made of a heat-resistant resin, a substrate having a known material and structure can be used without limitation. Typical examples include a glass substrate-a BT (bismaleimide-triazine) resin resin substrate, a glass substrate-an epoxy resin substrate, a glass substrate-
Polyimide resin substrate, paper substrate-phenol resin substrate, paper substrate-epoxy resin substrate, paper substrate-Teflon substrate, composite resin substrate, polyimide, epoxy, Teflon, etc. with iron, aluminum, copper, etc. as the metal core A flexible substrate made of a polyimide resin, a polyester resin, or the like, or a ceramic substrate made of alumina, aluminum nitride, glass ceramic, or the like. However, the material is not limited to these. Of course, these substrates are not limited to single-layer substrates, but may be multilayer substrates. If a through-hole is required in the heat-resistant insulating substrate, existing drilling techniques such as drilling, laser, and plasma can be used.

However, as a material of the insulating substrate made of the above-mentioned heat-resistant resin, a glass substrate-BT (bismaleimide-triazine) resin resin substrate is most preferable because it has high insulation properties and migration hardly occurs. Therefore, the present invention provides an insulating substrate comprising the heat-resistant resin,
A glass substrate-BT (bismaleimide-triazine) resin resin substrate is included.

Similarly, the material of the easily roughening resin layer, which is more easily roughened than the heat-resistant insulating resin, is not particularly limited, and photosensitive resin, thermosetting resin, thermoplastic resin, or any of these resins can be used. It may be a mixture or a copolymer. For example, as the photosensitive resin, a composition for curing an epoxy resin or an epoxy compound with a cationic polymerization type photoinitiator, a composition for curing an acrylate epoxy resin or an acrylate compound with a radical polymerization type photoinitiator, or the above composition Heat curing agent, phenolic resin, epoxy resin,
Thermosetting resins such as polyester resin and melamine resin,
A composition to which rubbers such as isoprene rubber and natural rubber are added can be used. As the thermoplastic resin, Teflon, polyethersulfone, polyphenylene oxide,
Examples thereof include cyclohexadiene-based polymers and polymers having a syndiotactic-type substituent arrangement such as syndiotactic polystyrene, for example, a polymer using a metallocene catalyst.

The easily roughening resin formed on the insulating substrate made of a heat-resistant insulating resin which is difficult to roughen is removed by a wet process using an oxidizing agent or a dry process such as a plasma method. Organic filler or inorganic filler for producing a dent serving as a mechanical anchor, it is preferable in that role to include at least one,
Even if such fillers are not included, the practice of the present invention is not hindered at all. In short, an insulating substrate (core substrate) made of a plurality of resins (layers) of a heat-resistant insulating resin and a resin that is relatively easily roughened compared to the heat-resistant insulating resin.
Is a problem.

The material of the upper insulating resin layer formed on the insulating substrate (core substrate) according to claim 1 of the present invention by a build-up method or a laminating method is not particularly limited. No, but photosensitive resin,
It may be a thermosetting resin, a thermoplastic resin, or a mixture or copolymer thereof. For example, as the photosensitive resin, a composition for curing an epoxy resin or an epoxy compound with a cationic polymerization type photoinitiator, a composition for curing an acrylate epoxy resin or an acrylate compound with a radical polymerization type photoinitiator, or the above composition A composition in which a thermosetting agent, a thermosetting resin such as a phenol resin, an epoxy resin, a polyester resin, and a melamine resin, and rubbers such as isoprene rubber and natural rubber can be used. As the thermoplastic resin, Teflon, polyether sulfone,
Examples thereof include polyphenylene oxide, cyclohexadiene-based polymers, and polymers having a syndiotactic-type substituent sequence such as syndiotactic polystyrene, for example, a polymer using a metallocene catalyst.

The upper insulating resin layer has an organic filler or an inorganic filler for removing thermal expansion characteristics and a dent serving as a mechanical anchor by being removed by a wet process using an oxidizing agent or a dry process such as a plasma process. The inclusion of at least one of the fillers does not hinder the practice of the present invention. It should be noted that there is no restriction on the relationship of the difficulty of roughening (roughening) between the easily roughening resin layer on the insulating substrate and the insulating resin formed on the insulating substrate (core substrate). However, it is determined individually based on characteristics such as insulation resistance.

According to the present invention, an upper insulating resin layer formed on the insulating substrate (core substrate) according to claim 1 by a build-up method or a laminating method, and formed on the insulating resin. The following is proposed as a configuration of a wiring layer to be performed. That is, the present invention provides a first resin layer made of a heat-resistant resin, which is difficult to roughen, formed between lower wiring layers and over the upper surface, and a first resin layer formed on the first resin layer, A second resin layer made of a resin that is easier to roughen than a heat-resistant resin forming the layer, an upper wiring layer formed on the second resin layer, the first resin layer and the second resin layer, The printed wiring board according to claim 1, further comprising a via that penetrates and electrically connects the upper wiring layer and the lower wiring layer.

By using the printed wiring board having such a structure, even if the first resin layer made of a heat-resistant resin, which is difficult to roughen, is formed between the lower wiring layers and over the upper surface, the roughening is easy. Since the first resin layer is covered with the second resin layer made of resin, it is easy to form wiring (upper wiring layer) thereon.

Here, the first resin layer is formed between the lower wiring layers and over the upper surface, but may be formed only between the lower wiring layers. That is, the present invention is formed on a first resin layer made of a heat-resistant resin which is difficult to roughen and formed between lower wiring layers, and on the first resin layer and the lower wiring layer,
A second resin layer made of a resin that is more easily roughened than a heat-resistant resin forming the first resin layer, an upper wiring layer formed on the second resin layer, and a second resin layer penetrating the second resin layer; 3. The printed wiring board according to claim 1, further comprising a via for electrically connecting the upper wiring layer and the lower wiring layer.

According to such a configuration, even if the first resin layer is formed using a heat-resistant resin that is difficult to roughen, the upper wiring layer is formed on the second resin layer that is easily roughened. Therefore, the adhesion between the upper wiring layer and the second resin insulating layer is good, and fine circuit wiring can be formed. The resin constituting the second resin layer may be the same as the easily roughened insulating resin layer on the insulating substrate (core substrate), or a different resin may be used.

The method of manufacturing a printed wiring board according to the present invention further comprises a step of forming an easily roughened insulating resin layer on a heat-resistant resin-made insulating substrate with a resin that is more easily roughened than the heat-resistant resin. Forming a through hole in the insulating substrate on which the easily roughening insulating resin layer is formed, roughening the surface of the insulating substrate on which the through hole is formed, and, after the surface roughening step, on the insulating substrate. Forming a thin film layer on the insulating substrate on which the thin film is formed, forming a plating resist layer on the insulating substrate, exposing and developing the plating resist layer, and removing a resist at a portion where a wiring pattern is to be formed. Exposing a part of the thin film layer; forming an electrolytic plating layer on the exposed thin film layer; removing the plating resist layer; and lowering the electrolytic plating layer in the thin film layer And remove all but the thin film layer Characterized in that it comprises a step of forming a wiring layer. According to such a manufacturing method, since a wiring layer can be formed without etching a copper foil, a finer and thinner wiring can be formed.

Further, in the method for manufacturing a printed wiring board according to the present invention, a step of forming a through hole on an insulating substrate made of a heat resistant resin, and the step of forming the through hole on the surface of the insulating substrate and the inner wall surface of the through hole. A step of forming an easily roughening insulating resin layer with a resin that is more likely to be roughened than a resin, a step of roughening the surface of the insulating substrate, and a step of forming a thin film layer on the insulating substrate after the surface roughening. Forming a plating resist layer on the insulating substrate on which the thin film is formed, exposing and developing the plating resist layer, removing a resist at a portion where a wiring pattern is to be formed, and exposing the thin film layer. Forming an electrolytic plating layer on the exposed thin film layer, removing the plating resist layer, and removing the thin film layers other than the thin film layer below the electrolytic plating layer to form a wiring layer Process and Characterized in that it comprises a. According to such a manufacturing method, since the easily roughening resin layer is formed on both the surface of the insulating substrate and the inner wall surface of the through hole, the adhesiveness with the wiring layer formed thereon is further excellent. ing.

As a method for forming a resin layer which is more easily roughened than the heat-resistant resin on the heat-resistant insulating substrate, when using a liquid material, a roll coater, a curtain coater,
Existing technologies such as screen printing can be used. If you need to improve the adhesion of the conductor on the inner wall of the through hole,
The easily roughening resin layer can be formed also on the inner wall surface of the through-hole by the existing through-hole printing technique using a metal mask or the like. When using a film-like material, an existing laminating technique can be used. The thickness of the easily roughening resin layer to be formed is in the range of 5 to 40 μm. When the thickness of the easily roughening resin layer is 5 μm or less, the adhesion strength of the wiring conductor decreases, and when it exceeds 40 μm, there is a possibility that a problem may occur in the reliability as an insulating layer. Preferably, a range of 10 to 30 μm, more preferably, 15 to 25 μm is used.

The resin layer formed on the heat-resistant insulating substrate, which is equal to or more easily roughened than the heat-resistant resin, has its surface roughened by a wet process using an oxidizing agent or a dry process such as a plasma process. Is done. A metal thin film layer can be formed on the roughened surface by using any thin film forming technique such as electroless plating, sputtering, or decomposition of an organic metal compound such as silver or platinum. The thin film here means
Not only a thin film formed by so-called sputtering or the like but also a conductor layer of 1 μm or less formed by electroless plating or decomposition of an organic metal compound is included.

That is, the present invention includes a case where the thin film layer is formed of a thin film formed by electroless plating, sputtering, or decomposition of an organometallic compound. In the present invention, since the surface is covered with the easily roughening resin layer while using the heat-resistant resin, the surface can be easily roughened. Therefore, the thin film layer can be easily formed on the surface by electroless plating, sputtering, or decomposition of an organometallic compound.

Next, a plating resist is formed on the insulating substrate on which the thin film layer is formed. As a method of forming a plating resist, when using a liquid material, existing techniques such as a roll coater, a curtain coater, and screen printing can be used. When using a film-like material, an existing laminating technique can be used.

After exposing and developing the plating resist to form a wiring opening pattern and exposing the underlying thin film layer, an electrolytic copper plating layer is formed by electrolytic plating. Thereafter, an unnecessary thin film layer is removed by etching to form a wiring layer. By using the photolithography technique without using the copper-clad substrate, a fine wiring layer of 100 μm or less can be easily formed from the first layer of the insulating substrate.

As the material of the wiring layer formed on the substrate surface or the inner wall of the through hole, a known conductive material can be used without any limitation. For example, copper, nickel, aluminum,
Gold, chrome, etc. can be selected. Of these, copper is most preferably used. In addition, these surfaces are subjected to acicular or granular plating by copper plating or an alloy plating of copper and nickel, zinc, cobalt, or the like, blackening treatment by a known technique, a persulfate etching solution or sulfuric acid-peroxide. Etching (soft etching) using a hydrogen-based etching solution or the like may be performed.

If necessary, an insulating resin layer and a wiring layer are alternately laminated above the insulating substrate on which the fine wiring layer is formed by a build-up method or the like to form a multilayer substrate. If necessary, even if the easily roughening resin layer is formed between the second and subsequent wiring layers and the wiring interlayer insulating resin layer, it does not depart from the gist of the present invention.

According to the present invention, a printed wiring board is obtained in which a fine wiring layer having a wiring width of 100 μm or less is formed from the first layer of the insulating substrate by using the foliolithography technique. Further, by providing the easily roughening resin layer between the fine wiring layer and the insulating substrate, a printed wiring board having a fine wiring layer with high adhesion reliability due to a mechanical anchoring effect can be obtained. Insulating board with copper foil (copper-clad board)
Since the thickness of the wiring layer can be reduced in the present invention as compared with the case where the wiring layer is formed by etching, a printed wiring board with less unevenness on the surface when multilayered is obtained.

[0033]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 2B is a sectional view of a printed wiring board 100 according to Embodiment 1 of the present invention. This wiring board 1
00 has a thickness of 25 μm on the upper and lower surfaces of the insulating substrate 1 made of a BT (bismaleimide-triazine) resin-glass composite material.
A coating layer 2 made of an easily insulating epoxy insulating resin is formed. On the inner wall surfaces of the coating layer 2 and the through hole 3, wiring layers 9 and 9 composed of a thin film layer 7 and an electrolytic copper plating layer 8 are formed. The wiring layer 9 has a thickness of 18 μm including the thin film layer 7 and the electrolytic copper plating layer 8. The wiring layers 9, 9 formed on the upper and lower surfaces of the printed circuit board 100 are electrically connected to each other via the wiring layer (the conductor 10 in the through hole) in the through hole.

Next, a method of manufacturing the printed circuit board 100 will be described with reference to FIGS. FIG.
As shown in (a), an epoxy insulating resin, which is easily roughened, is applied to a surface of a BT (bismaleimide-triazine) resin-glass composite material having no copper-clad layer by a roll coater to a thickness of 32 μm. And then cured at 150 ° C. for 2 hours to form the coating layer 2 of the easily roughening resin. Next, as shown in FIG. 1B, a through hole 3 is formed using a drill. Subsequently, the surface of the coating layer 2 on the insulating substrate 1 is polished so as to have a thickness of 25 μm, and the inner surface of the through hole 3 is cleaned.

Subsequently, the surface of the coating layer 2 is roughened with a potassium permanganate solution (45 g / l). Next, Sn-P
d) dipped in a colloid solution (Okuno Pharmaceutical; OPC-80) to adsorb the Pd catalyst nuclei. Next, as shown in FIG. 1 (c), the entire surface of the insulating substrate 1 including the coating layer 2 and the through hole 3 made of the easily roughening resin is formed by electroless copper plating (Okuno Pharmaceutical; build copper). The thin film layer 4 having a thickness of 5 to 1.0 μm is formed.

Then, as shown in FIG. 1D, a photosensitive dry film resist DF1 (Nippon Gohsei; NIT-225) having a thickness of 25 μm was formed using a hot laminator.
Is laminated on the thin film layer 4 to form a resist layer 5. Next, the patterns of the wiring layers on the upper and lower surfaces are exposed through a photomask 6 and developed using a 1% aqueous solution of sodium carbonate to form a wiring opening pattern 7 as shown in FIG.

Thereafter, the resist residue on the thin film layer 4 in the wiring opening pattern 7 is removed by acidic degreasing, and the exposed surface of the thin film layer 4 is exposed to a sulfuric acid-hydrogen peroxide-based etchant (OPC-400 manufactured by Okuno Pharmaceutical Co., Ltd.). ). Thereby, the adhesion between the thin film layer 4 and the electrolytic copper plating layer 8 described below can be improved. Then, as shown in FIG. 2B, copper sulfate electrolytic plating is performed through the thin film layer 4 to form an electrolytic copper plating layer 8 on the exposed thin film layer 4.

Then, as shown in FIG. 2C, the remaining plating resist layer 5 is peeled off. Thereafter, the thin film layer 4 exposed from the electrolytic copper plating layer 8 and the vicinity of the surface layer of the electrolytic copper plating layer 8 are soft-etched and removed using a persulfate-based etching agent (manufactured by Ebara Cordierite; PB-228). As shown in FIG. 2D, a first wiring layer 9 including an electrolytic copper plating layer 8 and a thin film layer 4 therebelow, and a through-hole conductor 10 as a wiring layer in the through-hole 3 are formed. .

(Embodiment 2) FIG. 4D shows a second embodiment of the present invention.
It is sectional drawing of the printed wiring board 200 which concerns on embodiment. In the wiring board 200, a coating layer 12 made of an easily roughening epoxy insulating resin having a thickness of 25 μm is formed on upper and lower surfaces of an insulating substrate 11 made of a BT (bismaleimide-triazine) resin-glass composite material. A through-hole inner coating layer 12 ′ is formed on the inner wall surface of the through-hole 13 provided in 11. Wiring layers 19 and 19 each including a thin film layer 14 and an electrolytic copper plating layer 18 are formed on the coating layer 12, and a through-hole conductor including the thin film layer 14 and the electrolytic copper plating layer 18 is formed on the coating layer 12 ′ in the through hole. 20 are formed. This wiring layer 19 is composed of the thin film layer 14 and the electrolytic copper plating layer 1.
8 together with a thickness of 18 μm. Wiring layers 19, 19 formed on the upper and lower surfaces of printed circuit board 200
Are electrically connected to each other via a wiring layer (the conductor 20 in the through hole) in the through hole.

As shown in FIG. 3A, a through-hole 1 is formed by drilling on an insulating substrate 11 made of a BT (bismaleimide-triazine) resin-glass composite material having no copper-clad layer.
Form 3 Next, as shown in FIG. 3 (b), a roughening epoxy insulating resin having a thickness of 25 μm is printed on the inner wall surface of the through hole 13 using a metal mask (not shown) at a thickness of 25 μm. After curing for 2 hours, a coating layer 12 'in the through-hole made of the easily roughening resin is formed. next,
As shown in FIG. 3 (c), after using a screen mask (not shown), the surface of the insulating substrate 11 other than the through holes 13 is printed with an easily roughening epoxy insulating resin to a thickness of 32 μm.
Cure at 150 ° C. for 2 hours to form coating layer 1 of easily roughening resin.
Form 2 After that, the surface of the coating layer 12 on the insulating substrate 11 is polished so as to have a thickness of 25 μm, and the surface thereof is leveled.
Wash.

Subsequently, the surfaces of the coating layers 12 and 12 'made of the easily roughening resin on the substrate are roughened with a potassium permanganate solution (45 g / l). Next, after immersing in a Sn-Pd colloid solution (Okuno Pharmaceutical; OPC-80) to adsorb the Pd catalyst nucleus, as shown in FIG. 3D, electroless copper plating (Okuno Pharmaceutical; Build 0.5) on the entire surface of the easily roughening resin coating layers 12 and 12 '
A 1.0 μm thin film layer 14 was formed.

Further, as shown in FIG. 3 (e), a photosensitive dry film resist DF1 (Nippon Gohsei; NIT-225) having a thickness of 25 μm was formed using a hot laminator.
Is laminated on the thin film layer 14 to form a resist layer 15. Next, the wiring patterns on the upper and lower surfaces are exposed through a photomask 16 and developed using a 1% aqueous solution of sodium carbonate to form a wiring opening pattern 17 as shown in FIG.

Thereafter, the opening pattern 17 is formed by acidic degreasing.
The resist residue in the inside is removed, and the surface of the exposed thin film layer 14 is exposed to a sulfuric acid-hydrogen peroxide-based etchant (Okuno Pharmaceutical; OP
C-400). Thereby, the thin film layer 14
And the adhesion with the electrolytic copper plating layer 18 described below can be improved. Then, as shown in FIG. 4B, copper sulfate-based electrolytic plating is performed through the thin film layer 14 to expose the exposed thin film layer 17.
An electrolytic copper plating layer 18 having a thickness of about 22 μm is formed on the substrate.

Then, as shown in FIG. 4C, after the remaining plating resist layer 15 is peeled off, the thin film layer 14 and the electrolytic copper plating are etched with a persulfate-based etching agent (Ebara Cordierite; PB-228). The vicinity of the surface layer of the layer 18 is removed by soft etching, and as shown in FIG. 4D, the first wiring layer 19 including the electrolytic copper plating layer 18 and the thin film layer 14 thereunder and the inside of the through hole are formed. A printed wiring board 200 having the conductor 20 is formed.

In the above, of the printed wiring boards 100 and 200 according to the first and second embodiments of the present invention,
Although the first layer which is a feature of the present invention has been described,
The second and subsequent layers of each printed wiring board will be described. (Embodiment 3) As shown in FIG. 5A, the insulating resin is filled in the through hole 3 of FIG. 2D in which the formation and connection of the first wiring layer 9 and the conductor 10 in the through hole are completed. After printing, it is cured at 150 ° C. for 2 hours to form the filling layer 30.

Then, as shown in FIG. 5B, the surface of the first wiring layer 9, the filling layer 30, and the roughened coating layer 2 of the printed wiring board 100 are coated with a roll coater using a roll coater.
After applying an insulating resin made of T resin with a thickness of 60 μm,
After curing at 150 ° C. for 2 hours, an insulating layer 21 of BT resin is formed. Since the insulating layer 21 is made of a BT resin, the insulating layer 21 has excellent insulation properties, but has difficulty in surface roughening.

Subsequently, as shown in FIG. 5C, an epoxy insulating resin having a thickness of 32 μm is printed on the surface of the insulating layer 21 of the BT resin, which is not easily roughened, at a temperature of 150 ° C.
For 2 hours to form the surface coating layer 22 of the easily roughening resin. Then, using an excimer laser, FIG.
As shown in (a), an opening pattern 23 for a retaining hole via is formed, and a part of the wiring layer 4 is exposed.

Subsequently, the surface coating layer 22 and the insulating layer 21
Is roughened with a potassium permanganate solution (45 g / l).
Next, a Sn-Pd colloid solution (Okuno Pharmaceutical; OPC-
80) to adsorb the Pd catalyst nuclei. Thereafter, a thin film layer 24 of 0.5 to 1.0 μm was formed on the upper surface of the wiring layer 9 exposed by electroless copper plating (manufactured by Okuno Pharmaceutical; build copper) and on the inner wall surface of the opening pattern 23 for the retaining hole via. Then, using a hot laminator, thickness 25μ
m not shown photosensitive dry film resist DF1
(NIT-225 manufactured by Nippon Synthetic Chemical Co., Ltd.) is laminated on the electroless copper plating thin film layer 24 to form a resist layer. Next, the wiring layer patterns on the upper and lower surfaces are exposed through a photomask, and are developed using a 1% aqueous sodium carbonate solution to form a wiring opening pattern. Next, the thin film layer 2
4, copper sulfate-based electrolytic plating is performed to form an electrolytic copper plating layer 28 having a thickness of about 22 μm on the exposed thin film layer 24. Then, after removing the remaining plating resist layer, a persulfate-based etching agent (Ebara Cordierite; P
B-228) Exposed thin film layer 24 and electrolytic copper plating layer 2
8 is removed by soft etching around the surface layer of FIG.
As shown in (b), the second wiring layer 29 and the retaining hole plated conductor 25 are formed to obtain the printed wiring board 300.

(Embodiment 4) The printed wiring board 200 of FIG. 4D is also laminated through the same steps as in Embodiment 3 to form a printed wiring board 400 as shown in FIG.
Get. In the printed wiring board 400, the insulating layer 31 is formed on the filling layer 40, the covering layer 12, and the wiring layer 19 formed in the through holes 13. The insulating layer 31 is made of a BT resin and has excellent insulation properties, but is difficult to roughen. Therefore, the surface of the insulating layer 31 is covered with a surface coating layer 32 made of an epoxy-based easily roughening resin. . On the surface of the surface coating layer, a thin film layer 34 and an electrolytic copper plating layer 38
Is formed. This wiring layer 39
Are electrically connected to the lower wiring layer 19 via the retaining hole plated conductor 35.

Further, the printed wiring boards 100 and 20
Another embodiment will be described with respect to a method for forming the second layer or more of layer 0. (Embodiment 5) A printed wiring board 100 shown in FIG. 2B is prepared, and as shown in FIG. 7A, an insulating resin is filled and printed in the through holes 3 and then cured at 150 ° C. for 2 hours. Then, an insulating filling layer 50 is formed.

Thereafter, an insulating resin made of BT resin is applied to the surface of the first wiring layer 8, the insulating filling resin layer 19 and the roughened insulating resin coating layer 2 by screen printing to a thickness of 30 μm. Cure at 150 ° C. for 2 hours.
Then, the surface is polished to expose the wiring layer 9, and FIG.
As shown in (b), an inter-wiring insulating layer 41 made of BT resin is formed between the first wiring layers 9. Wiring insulating layer 4
No. 1 is excellent in insulation because it is made of a BT resin, but roughening is difficult.

Thereafter, as shown in FIG. 7C, the surfaces of the first wiring layer 9, the insulating filling and filling layer 50 and the inter-wiring insulating layer 41 are roughened with an epoxy resin using a roll coater. Is applied at a thickness of 60 μm and cured at 150 ° C. for 2 hours to form a coating layer 42 made of an easily roughened insulating resin. Further, using an excimer laser, an opening pattern 43 for a retaining hole via is formed as shown in FIG. 8A, and a part of the upper surface of the wiring layer 9 is exposed.

Subsequently, the inner wall surface of the coating layer 42 and the opening pattern 43 for the via hole is roughened with a potassium permanganate solution (45 g / l). Next, it is immersed in a Sn-Pd colloidal solution (Okuno Pharmaceutical; OPC-80) to adsorb the Pd catalyst core. Thereafter, the coating layer 27, the inner wall surface of the opening pattern 43 for the retaining hole via and the exposed wiring layer 29 are formed by electroless copper plating (manufactured by Okuno Pharmaceutical; build copper).
Then, a thin film layer 44 of 0.5 to 1.0 μm was formed. Then, using a hot laminator, a photosensitive dry film resist DF1 (not shown) having a thickness of 25 μm (manufactured by Nippon Gohsei; NIT-225) is laminated on the thin film layer 44 to form a resist layer (not shown). Next, the upper and lower wiring layer patterns are exposed through a photomask,
Develop using a 1% aqueous solution of sodium carbonate to form a wiring opening pattern (not shown). Next, the thin film layer 4
4, copper sulfate-based electrolytic plating is performed to form an electrolytic copper plating layer 48 having a thickness of about 22 μm on the exposed thin film layer 44. Then, after removing the remaining plating resist layer, a persulfate-based etching agent (Ebara Cordierite; P
B-228), the thin film layer exposed in step B-228) and the vicinity of the surface layer of the electrolytic copper plating layer 48 are soft-etched and removed, and FIG.
As shown in FIG. 5, the electrolytic plating layer 48 and the thin film layer 4 thereunder are formed.
4 to form a printed wiring board 500.

(Embodiment 6) The printed wiring board 200 shown in FIG.
A printed wiring board 600 as shown in FIG. 8C is obtained. In the printed wiring board 600, the through hole 13 is
And an inter-wiring insulating layer 51 is formed between the wiring layers 19. Since the inter-wiring insulating layer 51 is made of BT resin, it has excellent insulating properties, but it is difficult to roughen the surface. On the upper surfaces of the inter-wiring insulating layer 51, the filling layer 60, and the wiring layer 19, a surface coating layer 52 made of an epoxy-based roughening resin is provided.
Are formed. A thin film layer 54 is provided on the surface of the surface coating layer.
And a wiring layer 59 composed of an electrolytic copper plating layer 58 is formed. The wiring layer 59 is electrically connected to the lower wiring layer 19 via the retaining hole plated conductor 55.

[0055]

As described above, according to the structure of the printed wiring board and the method of manufacturing the same of the present invention, even if an insulating substrate made of a resin that is difficult to roughen, such as a BT resin, is used, the first substrate can be used. A fine wiring layer can be formed from the first layer, and an easily roughening resin layer made of a resin that is more easily roughened than this resin is formed on a resin layer made of a resin that is difficult to roughen. Therefore, an anchoring effect for improving the adhesion between the wiring layer and the easily roughening resin layer can be easily obtained.

[Brief description of the drawings]

FIG. 1 shows a printed wiring board 10 according to a first embodiment of the present invention.
FIG. 2 is a partially enlarged cross-sectional view showing a No. 0 and a manufacturing method thereof.

FIG. 2 is a printed wiring board 10 according to the first embodiment of the present invention.
FIG. 2 is a partially enlarged cross-sectional view showing a No. 0 and a manufacturing method thereof.

FIG. 3 is a printed wiring board 20 according to a second embodiment of the present invention.
FIG. 2 is a partially enlarged cross-sectional view showing a No. 0 and a manufacturing method thereof.

FIG. 4 is a printed wiring board 20 according to a second embodiment of the present invention.
FIG. 2 is a partially enlarged cross-sectional view showing a No. 0 and a manufacturing method thereof.

FIG. 5 is a printed wiring board 30 according to a third embodiment of the present invention.
FIG. 2 is a partially enlarged cross-sectional view showing a No. 0 and a manufacturing method thereof.

FIG. 6 is a partially enlarged cross-sectional view showing printed wiring boards 300 and 400 according to Embodiments 3 and 4 of the present invention and a method for manufacturing the same.

FIG. 7 shows a printed wiring board 50 according to a fifth embodiment of the present invention.
FIG. 2 is a partially enlarged cross-sectional view showing a No. 0 and a manufacturing method thereof.

FIG. 8 is a partially enlarged cross-sectional view showing printed wiring boards 500 and 600 according to Embodiments 5 and 6 of the present invention and a method for manufacturing the same.

[Explanation of symbols]

 1, 11: insulating substrate 2, 12: coating layer 4, 14, 24, 34, 44, 45: thin film layer 8, 18, 28, 38, 48, 58: electrolytic copper plating layer 9, 19, 29, 39, 49, 59: wiring layer 10, 20: conductor in through hole 12 ': coating layer in through hole 30, 40, 50, 60: filling layer 45, 55: fastening hole plated conductor

Continued on the front page (51) Int.Cl. ⁶ Identification code FI H05K 3/46 H05K 3/46 E

Claims (6)

[Claims] An insulating substrate made of a heat-resistant resin that is difficult to roughen; an easily-roughened insulating resin layer formed on the insulating substrate and made of a resin that is more easily roughened than the heat-resistant resin; A printed wiring board, comprising: a wiring layer formed on an easily roughening insulating resin layer. 2. An insulating substrate made of a heat-resistant resin which is difficult to roughen, a through hole formed in the insulating substrate, a surface of the insulating substrate and an inner wall surface of the through hole, A printed wiring board, comprising: a roughening insulating resin layer made of a resin that is easier to roughen than a resin; and a wiring layer formed on the roughening insulating resin layer. 3. A first resin layer made of a heat-resistant resin, which is difficult to roughen, formed between lower wiring layers and over the upper surface, and a first resin layer formed on the first resin layer, Of a resin that is easier to roughen than a heat-resistant resin that forms
A resin layer, an upper wiring layer formed on the second resin layer, a via penetrating the first resin layer and the second resin layer, and electrically connecting the upper wiring layer and the lower wiring layer. The printed wiring board according to claim 1, comprising: 4. A first resin layer formed between a lower wiring layer and made of a heat-resistant resin which is difficult to roughen, and a first resin layer formed on the first resin layer and the lower wiring layer. A second resin layer made of a resin that is easier to roughen than a heat-resistant resin forming the second resin layer; an upper wiring layer formed on the second resin layer;
The printed wiring board according to claim 1, further comprising a via penetrating through the resin layer and electrically connecting the upper wiring layer and the lower wiring layer. 5. A step of forming an easily roughened insulating resin layer on a insulating substrate made of a heat resistant resin using a resin which is easier to roughen than the heat resistant resin; and forming the easily roughened insulating resin layer. A step of forming a through hole in the insulating substrate, a step of roughening the surface of the insulating substrate having the through hole, a step of forming a thin film layer on the insulating substrate after the surface roughening step, A step of forming a plating resist layer on the formed insulating substrate; a step of exposing and developing the plating resist layer to remove a resist at a portion where a wiring pattern is to be formed and exposing a part of the thin film layer Forming an electrolytic plating layer on the exposed thin film layer, removing the plating resist layer, removing the thin film layer other than the thin film layer below the electrolytic plating layer, forming a wiring layer Forming 2. The method for manufacturing a printed wiring board according to claim 1, wherein: 6. A step of forming a through-hole on an insulating substrate made of a heat-resistant resin, and the step of forming a through-hole on the surface of the insulating substrate and the inner wall surface of the through-hole with a resin which is more easily roughened than the heat-resistant resin. A step of forming a conductive insulating resin layer; a step of roughening the surface of the insulating substrate; a step of forming a thin film layer on the insulating substrate after the surface roughening; and a plating resist on the insulating substrate on which the thin film is formed. Forming a layer, exposing and developing the plating resist layer, removing a resist at a portion where a wiring pattern is to be formed, and exposing the thin film layer; and forming an electrolytic plating layer on the exposed thin film layer. Forming a wiring layer, removing the plating resist layer, removing the thin film layer other than the thin film layer below the electrolytic plating layer in the thin film layer, and forming a wiring layer. , Claim 2 Method for manufacturing a printed wiring board according.