JPH07202433A - Multilayer printed wiring board and production thereof - Google Patents

Abstract

PURPOSE:To enhance smoothness and reliability in connection by coating an inner layer circuit board with a liquid filler composed of a solventless photosensitive resin composition and laminating a film-like adhesive thereon to form a resin insulating layer. CONSTITUTION:A through hole 7 is made through a double-sided copper clad laminate and then an inner layer substrate 1 having inner layer conductor circuits on the opposite sides is produced. The inner layer substrate 1 is immersed into a liquid tiller to fill the through hole 7 therewith and an adhesive dry film is laminated thus forming a composite resin insulating layer, comprising a tiller layer 2 and an adhesive film applied layer 3, on the opposite sides of the inner layer substrate 1. The substrate formed with the resin insulating layer is then exposed using a mask for forming a via hole and developed thus forming a via hole 8 in the resin insulating layer. The resist film is hot pressed and heat treated to form a resist layer 5. It is further subjected to electroless copper plating thus producing a printed wiring board having a conductor pattern 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a multilayer printed wiring board and a multilayer printed wiring board manufactured under this method, and more particularly to a through hole, a via hole or a conductor circuit between inner layers. By excluding foreign matter and air bubbles from getting into the gap caused by the step, and by filling the liquid filler densely, the smoothness is excellent,
And, we propose the technology to manufacture the multilayer printed wiring board with high connection reliability.

[0002]

2. Description of the Related Art A multilayer printed wiring board has conductor circuits and resin insulation layers that are alternately laminated, and circuits of the inner and outer layers are
These are connected and conducted by through holes or via holes. Therefore, in general, this multilayer printed wiring board inevitably has microscopic unevenness caused by through holes, via holes, or steps between circuits,
There is a problem that the so-called smoothness is poor.

Conventionally, in order to overcome such problems,
Before forming the resin insulating layer, a method of previously filling the through hole, the via hole or the step between the circuits with the resin by a so-called dipping method of immersing the inner layer circuit board in the resin liquid has been adopted.

[0004]

However, in the above-mentioned prior art, the inside of the hole of the through hole or the via hole,
Alternatively, there is a fatal defect that dust or air bubbles are apt to cause residual adhesion at the step between circuits. Moreover, there is a drawback in that the surface irregularities resulting from this become more severe, making it difficult to control the film thickness of the resin insulating layer. Moreover, this conventional technique has a drawback that it is extremely difficult to control the film formation such as the viscosity and amount of the resin liquid.
Therefore, there is a drawback that reliability such as film thickness accuracy of the resin insulating layer is deteriorated, and eventually the reliability and productivity of the printed wiring board are deteriorated.

An object of the present invention is to eliminate the above-mentioned problems of the prior art, and in particular, to prevent foreign matters from entering into the gaps caused by through holes, via holes, or steps between conductor circuits provided in the inner layer circuit. It is an object of the present invention to provide a technique for advantageously manufacturing a multilayer printed wiring board having excellent smoothness and high connection reliability by densely filling a liquid filler by eliminating inclusion and entrainment of bubbles.

[0006]

As a result of intensive studies aimed at achieving the above object, the inventor has come up with the present invention having the following contents. That is, a method for manufacturing a multilayer printed wiring board according to the present invention is a method for manufacturing a multilayer printed wiring board, which comprises a plurality of conductor circuits electrically insulated by a resin insulating layer, the inner layer circuit having a through hole or a via hole. On the plate, a liquid filler composed of a solventless photosensitive resin composition is supplied and adhered, and a film-like adhesive is superposed on the upper layer thereof, followed by pressing and laminating under reduced pressure, thereby the filler. A method for manufacturing a multilayer printed wiring board, which comprises forming a resin insulating layer composed of a composite layer of a layer and an adhesive layer.

Further, the present invention is a more preferable embodiment by the following method. That is,
As the solventless photosensitive resin composition, it is desirable to use a mixture of a photosensitive resin and a thermosetting resin, and it is desirable to use a composition containing an inorganic filler. Furthermore, the above-mentioned adhesive exhibits a property that a hardened heat-resistant resin fine powder that is soluble in an acid or an oxidant is hardly soluble in an acid or an oxidant when it is hardened. It is preferable to use an adhesive that is dispersed in an uncured heat-resistant resin matrix.

The multilayer printed wiring board of the present invention obtained by such a manufacturing method is a multilayer printed wiring board in which a plurality of layers of conductor circuits are electrically insulated by a resin insulating layer. A composite of a filler layer made of a photosensitive resin composition filled in a gap formed by a through hole, a via hole, or a step between conductor circuits provided in an inner layer circuit board, and an adhesive layer covering the upper layer thereof. It is a multilayer printed wiring board characterized by comprising layers.

Here, the above-mentioned photosensitive resin composition is preferably a mixture of a photosensitive resin and a thermosetting resin, and preferably contains an inorganic filler. Further, the adhesive layer has a characteristic that a hardened heat-resistant resin fine powder that is soluble in an acid or an oxidizing agent is hardly soluble in an acid or an oxidizing agent when the hardening treatment is performed. It is preferable to use an adhesive which is dispersed in the uncured heat-resistant resin matrix shown.

[0010]

The feature of the present invention is that the inner layer circuit board is mainly laminated with a liquid filler made of a photosensitive resin composition and a film-like adhesive under reduced pressure, thereby mainly exerting an effect of filling uneven steps. That is, the resin insulating layer is composed of a composite layer of a filler layer made of a photosensitive resin composition and an adhesive layer covering the upper layer, which mainly exhibits an effect of preventing foreign matter from entering. As a result, it is possible to eliminate the mixing of foreign matter and the entrainment of air bubbles in the gap caused by the through hole, the via hole provided in the inner layer circuit, or the step between the conductor circuits, and to densely fill the liquid filler. It is possible to advantageously manufacture a multilayer printed wiring board having excellent smoothness and high connection reliability.

That is, according to the present invention: By using the liquid filler, it is possible to smoothly fill the through holes, the via holes provided in the inner layer circuit or the gaps (dents) caused by the step between the conductor circuits, and at the same time, by using the vacuum laminator, Since the insulating layer can be continuously formed, a multilayer printed wiring board excellent in smoothness and productivity can be manufactured at low cost. ． By covering the upper layer of the filler layer with a film-like adhesive, it is possible to prevent dust and foreign matter from entering, and improve the reliability of the resin insulating layer. Moreover, by using a film-like adhesive, it is possible to form a resin insulating layer having excellent smoothness, easy film thickness control, and excellent film thickness accuracy. ． By laminating under reduced pressure, inclusion of bubbles can be prevented.

The method for producing the multilayer printed wiring board of the present invention will be described below. First of all, in manufacturing,
An inner layer circuit board provided with through holes or via holes as required is manufactured by a conventional method. Here, as the substrate used for the inner layer circuit board, for example, a plastic substrate, a ceramic substrate, a metal substrate, a film substrate or the like can be used. For example, a glass epoxy substrate, a glass polyimide substrate, an alumina substrate, a low temperature fired ceramic substrate, an aluminum nitride substrate, an aluminum substrate, an iron substrate and a polyimide film substrate.

Next, a liquid filler composed of a solventless photosensitive resin composition is supplied and adhered onto the inner layer circuit board produced as described above, and then a film-like adhesive is applied onto the liquid filler. The agents are overlaid, and the films are laminated under reduced pressure while pressing the films from both sides of the substrate to scrape them. By the work in this step, the resin insulating layer including the composite layer of the filler layer and the adhesive layer is formed. Here, there are various methods as shown in FIGS. 1 to 4, for example, as a method of depositing a liquid filler on a substrate, superposing an adhesive film and laminating it under reduced pressure. FIG. 1 is a diagram showing a method of immersing a substrate in a liquid filler to deposit the liquid filler on the entire surface of the substrate, feed the substrate to a vacuum laminator, and laminate the adhesive film. FIG. 2 is a diagram showing a method of applying a liquid filler on a substrate with a roll coater or the like to adhere the liquid filler to the entire surface of the substrate and feeding the substrate to a vacuum laminator to laminate an adhesive film. Is. Figure 3
It is a figure which shows the method of making a liquid filler adhere to the edge part of both surfaces of a board | substrate using a chemical dropper, etc., and sending this board edge part to a vacuum laminator first, and laminating an adhesive film. FIG. 4 shows the liquid filler is supplied to the roll kiss portion of the rolling roll of the vacuum laminator by jetting or the like, and the substrate is fed to the roll kiss portion to supply the liquid filler to the substrate and laminate the adhesive film. It is a figure which shows the method of performing simultaneously.

In the present invention, as the liquid filler,
The reason why the solventless photosensitive resin composition is used is that in a composition containing a solvent, the solvent is volatilized and the viscosity is changed in a low pressure state. The photosensitive resin composition is preferably a mixture of a photosensitive resin and a thermosetting resin. The reason for this is that when a composition containing only a photosensitive resin is used, exposure light does not reach the resin filled in the through hole or the via hole, resulting in insufficient photo-curing. Further, this photosensitive resin composition preferably contains an inorganic filler such as silica, alumina, zirconia or talc. This is because curing shrinkage is reduced.

In the present invention, the film adhesive is pressed from both sides sandwiching the substrate and laminating under reduced pressure while scratching, but it is desirable to carry out the lamination under the following conditions. ． Degree of vacuum: 2-3 torr. Roll pressure: 3kgf / cm ² . Roll temperature: 80 ℃. Transport speed: 2m / sec

The next step is a treatment for roughening the surface of the resin insulating layer provided on the substrate as described above. In order to facilitate the roughening of the surface of the resin insulating layer, in the present invention, when forming the resin insulating layer, the adhesive layer covering the filler layer is soluble in an acid or an oxidizing agent. A film of a heat-resistant resin fine powder that has been cured, and is dispersed in an uncured heat-resistant resin matrix that has the property of being sparingly soluble in acid or oxidant when cured. It is preferable to use an adhesive. The surface roughening treatment of the resin insulation layer including the adhesive layer is performed by immersing the substrate on which the resin insulation layer is formed in a solution of an acid or an oxidant, or spraying the substrate with an acid or an oxidant solution. Thus, at least a part of the heat resistant fine powder dispersed on the surface of the adhesive layer forming the resin insulating layer can be dissolved and removed. By such a treatment, the surface of the resin insulating layer becomes a roughened surface suitable for plating. Here, the oxidizing agent for roughening the adhesive layer is preferably chromic acid, chromate salt, permanganate, ozone or the like, and the acid is preferably hydrochloric acid, sulfuric acid, organic acid or the like. For the purpose of effectively dissolving and removing the heat-resistant resin fine powder, the surface portion of the adhesive layer is lightly roughened in advance, for example, by polishing with a fine powder abrasive or liquid honing. That is extremely effective.

Then, for example, electroless plating is applied to the surface of the roughened resin insulation layer to form a necessary conductor pattern, and the above-mentioned steps are repeated as necessary to obtain a desired multilayer printed wiring. Get the board. As this electroless plating, for example, electroless copper plating, electroless nickel plating, electroless tin plating, electroless gold plating and electroless silver plating can be applied, and especially electroless copper plating, electroless nickel plating and electroless plating It is preferable to use at least one method of gold plating. In addition,
In the manufacturing method of the present invention, different types of electroless plating or electroplating may be performed on the electroless plating, or solder may be coated.

In the method of the present invention, the conductor circuit described above can also be formed by various methods that have been carried out for known printed wiring boards. For example,
A method of etching a circuit after applying electroless plating to the substrate or a method of directly forming a circuit when applying electroless plating may be applied.

The multilayer printed wiring board of the present invention manufactured under the manufacturing method of the present invention as described above will be described. The multilayer printed wiring board of the present invention is a multilayer printed wiring board in which a plurality of layers of conductor circuits are electrically insulated by a resin insulating layer, and the resin insulating layer is provided with through holes and vias provided in the inner layer circuit board. A hole or a gap formed by a step between conductor circuits is formed in a composite layer including a filler layer made of a photosensitive resin composition and an adhesive layer covering the upper layer of the photosensitive resin composition. And a double-sided through-hole printed wiring board formed by forming a conductor circuit via a resin insulating layer on both sides of the substrate and through holes, and
There is a build-up multilayer wiring board in which a conductor circuit is formed in multiple layers on a substrate on which a conductor layer is formed with an interlayer insulating layer (resin insulating layer) having via holes.

[0020]

【Example】

(Example 1) (1) 35 parts by weight of a flame-retardant epoxy resin (made by oiled shell) softened and liquefied at 85 ° C., 30 parts by weight of bisphenol A type epoxy resin (made by oiled shell) and a curing agent 35 parts by weight of acid anhydride type curing agent (manufactured by ThreeBond) and 0.5% of imidazole type curing agent (manufactured by Shikoku Kasei) as a curing accelerator
The mixture of parts by weight was kneaded with a three-roll mill to prepare a liquid filler having a solid content of 100%. According to JIS-K7117, the viscosity of this filler was measured with a digital viscometer manufactured by Tokyo Keiki Co., Ltd. at 20 ° C. for 60 seconds.
It was 3.1 Pa · s at 0 Pa · s and 60 rpm, and its SVI value (thixotropic property) was 2.2. (2) After forming a through hole with a diameter of 0.2 mm on the double-sided copper clad laminate with a drill and applying an active catalyst to the entire surface to activate it,
Electroless plating was performed according to a conventional method to deposit copper on the inner wall of the through hole to form a through hole 7. (3) Inner layer substrate 1 having inner layer conductor circuits 4 on the front and back by a normal subtractive method after forming through holes 7.
Was created (see Fig. 5 (a)). (4) Immerse the inner layer substrate 1 prepared in (3) above in the liquid filler prepared in (1) above to deposit resin on the entire surface to fill the through holes 7, and then to apply simultaneous double-sided vacuum. An adhesive dry film was laminated using a laminator (manufactured by Hitachi Chemical Co., Ltd.) to form a composite resin insulating layer composed of the filler layer 2 and the adhesive film sticking layer 3 on both surfaces of the inner layer substrate 1 (Fig. 5 (b )). Here, as the dry film, an adhesive having a composition prepared by the following will be used. The laminating condition at this time is that the roller is rubber-like and the pressure of the roll is 3 kg / cm ² , The roll temperature is 50 ℃, the transfer speed is 2m / min, and the low pressure condition (2
~ 3 torr). ． Cresol novolac type epoxy resin (molecular weight: approx.
65 vol% 50% acrylate of 4000, epoxy equivalent: 220, melting point: 90-95 ℃, bisphenol A type epoxy resin (molecular weight: about 900, epoxy equivalent: 450, melting point: 60-
75 ° C) 16 vol%, dipentaerythritol hexaacrylate (molecular weight: about 300) 3 vol% and neopentyl glycol modified trimethylolpropane diacrylate (molecular weight: about 300) 3 vol%, ethylene glycol monobutyl ether acetate (BCA) To prepare a resin solution. ． Epoxy resin fine powder (particle size 0.5 μm) 5.5 vol%
The solvent was added to and dispersed by ultrasonic vibration to obtain a suspension. ． The resin solution prepared above was added to the suspension prepared above in 5 batches, and each time the resin solution was added, it was passed through a sand mill filled with zirconia balls of 2 mmφ and mixed. ． In the resin liquid prepared above, 5.1 vol% of epoxy resin fine powder (particle size 5.5 μm), Teflon fine particles (manufactured by Daikin Industries, Ltd., PTFE: particle size 5 μm) 5 vol%, Veszophenone 5 vol%, Michler's ketone 1 vol% and imidazole 6% of a system hardening accelerator was added and mixed by a sand mill. ． After adding 1 vol% of an acrylic leveling agent to the resin liquid prepared above, they were mixed with a homodisper stirrer to obtain a photosensitive resin solution having a solid content concentration of 65%. ． The photosensitive resin solution obtained above was applied onto a mud-treated 15 μm thick polypropylene film using a doctor blade, and then dried in a hot air circulation oven at 80 ° C. for 5 minutes to obtain a thickness of Is 40 μm and residual solvent ratio is 1.5 wt
% Sheet-like adhesive was obtained. (5) The substrate on which the resin insulation layer was formed in (4) above was exposed with a double-sided simultaneous exposure machine (manufactured by Hitec) through a mask for forming via holes at an exposure amount of 300 mj, and then Etana IR (Asahi Kasei ) For 60 seconds to form a via hole 8 in the resin insulating layer. Further, this resin insulation layer was irradiated with ultraviolet rays (UV cured) and then heat treated to form a resin insulation layer having a via hole 8 (thickness 40 μm) (see FIG. 5C). (6) Immerse the substrate on which the adhesive layer was formed in an aqueous solution of chromic anhydride 800 g / l adjusted to 70 ° C (the ratio of Cr ^{3+ to} the total Cr was 0.50% at this time) for 20 minutes, Surface roughening was performed. The obtained surface has a surface roughness R _Z = 12 μm and R _a = 2.0.
was μm. (7) After roughening the surface, wash with water and wash with sodium sulfite 40
It was immersed in a 0 g / l aqueous solution at room temperature for 20 minutes to neutralize Cr ⁶⁺ . After washing with water, wash with hot water at 70 ° C for 20 minutes, then with water,
It was dried at 80 ° C for 10 minutes. (8) The substrate was degreased by a conventional method, subjected to hydrophilic treatment with a surfactant, acid-treated and then provided with a Pd Sn colloid catalyst, and then acid-treated again to remove unnecessary Sn. At this time, the amount of Pd adsorbed on the surface was 5 μg / cm ² . (9) After applying the catalyst, heat treatment was performed at 120 ° C. for 40 minutes to fix the catalyst nuclei on the surface. (10) Preheat the substrate to 80 ℃ and apply the resist film (dry film resist) prepared by the following method to 100 ℃
After that, thermocompression bonding was performed, and thereafter, exposure, development, UV curing, and heat treatment were performed by a conventional method to form a resist layer. As the developing solution, 1,1,1-trichloroethane was used. ． Cresol novolac type epoxy resin (molecular weight about 40
65 vol% of 50% acrylate with 00, epoxy equivalent 220, melting point 90-95 ° C, bisphenol A type epoxy resin (molecular weight about 900, epoxy equivalent 450, melting point 60-75 ° C) 16 vol
%, Dipentaerythritol hexaacrylate (molecular weight about 300) 3 vol% and neopentyl glycol modified trimethylolpropane diacrylate (molecular weight about 300)
) 3 vol% was dissolved in BCA to prepare a resin liquid. ． 5% by volume of benzophenone,
1 vol% of Michler's ketone and 6 vol% of imidazole curing accelerator were added and mixed in a sand mill. ． Acrylic leveling agent 1 to the resin liquid created in
After adding vol%, the mixture was mixed with a homodisper stirrer to obtain a photosensitive resin solution having a solid content concentration of 65 wt%. ． After coating the photosensitive resin solution obtained in above with a mud-treated polypropylene film with a thickness of 15 μm using a doctor blade, it is dried in a hot air circulation oven at 80 ° C. for 5 minutes to give a thickness of 40 μm. A sheet resist film with a residual solvent ratio of 1.5 wt% was obtained. (11) After activating the catalyst by acid treatment, it is shown in Table 1 by a conventional method.
A printed wiring board was manufactured by immersing in an electroless copper plating solution having the composition shown in 11 hours for electroless copper plating with a plating film thickness of 25 μm (see FIG. 5 (e)). At this time, the step difference between the resist and the conductor pattern formed by the plating film was 5 μm.

[0021]

[Table 1]

Example 2 A multilayer printed wiring board consisting of 4 layers was manufactured in the same manner as in Example 1 except that the liquid filler was applied by a roll coater (manufactured by Dainippon Screen) and laminated under reduced pressure. . The coating conditions used at this time were a coating roll for medium and high viscosity resist (manufactured by Dainippon Screen), a gap between the coating roll and the doctor bar of 0.4 mm, and a gap between the coating roll and the backup roll of 1.4 mm.
And the transport speed was 200 mm / s.

Example 3 A multilayer printed wiring board consisting of four layers was manufactured in the same manner as in Example 1 except that a liquid filler was attached to the tip of the substrate using a chemical dropper and laminated under reduced pressure. did.

Example 4 The liquid filler is supplied to the roll kiss portion of the rolling roll of the vacuum laminator, and the substrate is fed to this roll kiss portion, whereby the liquid filler is supplied to the substrate and lamination under reduced pressure is performed. A multilayer printed wiring board consisting of four layers was manufactured in the same manner as in Example 1 except that the above steps were performed simultaneously.

(Comparative Example 1) The inner layer substrate was dipped in a tank containing a liquid filler and then taken out. Then, the excess filler on the inner layer substrate was removed by a squeegee, and the inner layer through hole was filled with the liquid. A multilayer printed wiring board was produced in the same manner as in Example 1 except that the filler was filled.

With respect to the multilayer printed wiring board manufactured in this manner, whether foreign matter is mixed in or air bubbles are trapped in the gaps caused by through holes, via holes, or steps between conductor circuits, the smoothness of the resin insulation layer, and the connection reliability are ensured. The sex was evaluated. The results are shown in Table 2. As is clear from the results shown in Table 2, the multilayer printed wiring board according to the present invention was found to be superior to the prior art in any of the items.

[0027]

[Table 2]

A method for evaluating the presence or absence of the inclusion of foreign matter or the inclusion of bubbles, the smoothness of the resin insulation layer, and the connection reliability will be described. (1) Presence of foreign matter The number of foreign matter having a size of 10 μm or more within 30 mm □ in the central part of the substrate was measured and evaluated. (Number of samples N = 5) (2) Presence / absence of air bubbles After filling the φ0.2 mm through hole (N = 30) with resin,
The through-hole portion was cut, and the presence or absence of 10 μm or more in the cross-section inside the through-hole was examined. (3) Smoothness of Resin Insulation Layer After forming the resin insulation layer, the resin insulation layer was cut and the cross section thereof was observed with a microscope to evaluate the unevenness of the surface of the resin insulation layer (sample number N = 5). (4) Connection reliability of the resin insulation layer After forming the resin insulation layer and cutting it, and observing the cross section with a microscope, the interlayer adhesion between the filling filler and the resin insulation layer can be separated, lifted, and Evaluation was made based on the presence or absence (number of samples N = 5).

[0029]

As described above, according to the present invention, foreign matter is mixed into a gap formed by a through hole, a via hole provided in an inner layer circuit or a step between conductor circuits,
The inclusion of air bubbles can be eliminated and the liquid filler can be densely filled, and a multilayer printed wiring board having excellent smoothness and high connection reliability can be advantageously manufactured.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a technique for forming a resin insulating layer according to the present invention.

FIG. 2 is a diagram showing another embodiment of a technique for forming a resin insulating layer according to the present invention.

FIG. 3 is a diagram showing another embodiment of the resin insulating layer forming technique according to the present invention.

FIG. 4 is a diagram showing another embodiment of the technique for forming a resin insulating layer according to the present invention.

FIG. 5 is a manufacturing process diagram showing an embodiment of the present invention.

[Explanation of symbols]

 1 Inner Layer Substrate 2 Filler Layer 3 Adhesive Layer 4 Inner Layer Conductor Circuit 5 Resist 6 Conductor Circuit 7 Through Hole 8 Via Hole

Claims (8)

[Claims] 1. A method for manufacturing a multilayer printed wiring board comprising a plurality of conductor circuits electrically insulated by a resin insulation layer, wherein a solventless photosensitive resin is provided on an inner layer circuit board having through holes or via holes. A composite layer of a filler layer and an adhesive layer is obtained by supplying and adhering a liquid filler composed of the composition, superposing a film-like adhesive on the upper layer, and pressing and laminating under pressure reduction. A method for manufacturing a multilayer printed wiring board, which comprises forming a resin insulating layer made of 2. The method according to claim 1, wherein the solventless photosensitive resin composition uses a mixture of a photosensitive resin and a thermosetting resin. 3. The method according to claim 1, wherein the solventless photosensitive resin composition contains an inorganic filler. 4. The above-mentioned adhesive becomes insoluble in an acid or an oxidant when a cured heat-resistant resin fine powder which is soluble in an acid or an oxidant is hardened. The manufacturing method according to claim 1, wherein an adhesive is used which is dispersed in an uncured heat-resistant resin matrix exhibiting characteristics. 5. A multilayer printed wiring board comprising a plurality of conductor circuits electrically insulated by a resin insulation layer,
This resin insulation layer is filled with a filler layer made of a photosensitive resin composition, which is filled in a gap formed by a through hole, a via hole, or a step between conductor circuits provided in an inner layer circuit board, and an upper layer thereof. A multi-layer printed wiring board comprising a composite layer including an adhesive layer. 6. The photosensitive resin composition according to claim 5, wherein the photosensitive resin composition is a mixture of a photosensitive resin and a thermosetting resin.
The multilayer printed wiring board according to. 7. The multilayer printed wiring board according to claim 5, wherein the photosensitive resin composition contains an inorganic filler. 8. The adhesive layer is made of a cured heat-resistant resin fine powder that is soluble in an acid or an oxidizing agent and is hardly soluble in an acid or an oxidizing agent when subjected to a curing treatment. The multilayer printed wiring board according to claim 5, comprising an adhesive dispersed in an uncured heat-resistant resin matrix exhibiting the following characteristics.