JP2001036252A - Multilayer printed wiring board and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the embedding properties of an inner layer circuit of an insulating material satisfactory by overlapping a plurality of alternately laminating materials, such as film-like wiring boards and a fusible film for interlayer connection, on upon another, and integrating these overlapped materials through fusion. SOLUTION: A film-like insulator 1, made of a thermoplastic resin composition having a prescribed composition and heat characteristics has through-holes 2 formed by a laser beam for machining, in a manner of passing through both surfaces of the insulator 1. The holes 2 are filled with a conductive paste 3 to form a fusible film 4 for interlayer connection of a laminated electrical circuit. Furthermore, sheets of conductor foil are fused onto both surfaces of the film 4 using a vacuum heat press, and unwanted portions of the conductor foil are then removed to form conductive circuits 5. A plurality of sheets of laminated materials selected from among boards 6 and 7 and the film 4 are overlapped for lamination and integration by fusion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a multilayer printed wiring board and a method for manufacturing the same, and more particularly, to a multilayer printed wiring board having an insulating layer made of a thermoplastic resin and a method for manufacturing the same.

[0002]

2. Description of the Related Art In order to respond to recent demands for smaller, lighter, faster, and more sophisticated electronic devices, the degree of integration of semiconductors mounted on printed wiring boards has increased, the number of pins has increased, and the spacing between semiconductors ( Pitch) has decreased, and the demand for higher functionality in multilayer printed wiring boards has been increasing day by day.

The multilayer printed wiring board used in such a situation is made of a resin multilayer board using a prepreg in which fibers such as epoxy resin are impregnated as an insulating material, and is formed on a copper-clad laminate. In order to enable connection between the layers of the electric circuit, a through hole having a hole diameter of about 0.3 to 1.2 mm called a via hole (plated through hole in which no component is inserted) or a through hole is provided in the layer thickness direction. Things.

[0004] The formation density of through-holes in a multilayer printed wiring board has been increasing in accordance with the demand for higher functionality as described above.
Forming through-holes by drilling in order to cope with a high wiring density of, for example, 50 to 150 μm in wiring pitch has been an obstacle to a demand for a higher density circuit of a multilayer printed wiring board. In order to cope with such a problem, a multilayer printed wiring board having a build-up layer in which a through hole such as a via hole having a microscopic hole diameter (microscopic via hole) has been developed.

[0005] A multilayer printed wiring board having a build-up layer is a resin film with a copper foil in which a small-diameter via hole is formed by laser processing or etching using a normal wiring board in which a required number of through holes are formed in advance as a base (substrate). (Build-up layer) is stacked on the base and bonded and integrated, or all layers are formed by laminating build-up layers in which via holes of small diameter are formed.

As shown in FIGS. 2 (a), 2 (b) and 2 (c), a multilayer printed wiring board in which all six layers are formed by build-up layers, first impregnates a non-woven fabric with an epoxy resin. A prepared hole 11 penetrating both sides is formed in the prepreg by laser processing, a conductive paste 12 is filled in the prepared prepreg by a printing method, laminated with a copper foil by a vacuum hot press, and the prepreg and the conductive paste are cured.

[0007] Next, a circuit pattern 13 is formed by etching the copper foil, so that a double-sided wiring board 14 is formed as a core layer, and a prepreg 15 in which a pilot hole 11 is separately formed and a conductive paste 12 is filled. And copper foil 16
Are aligned on both surfaces of the core layer, and are again subjected to hot pressing and patterning (forming a circuit pattern by etching) to obtain a four-layer substrate 17 as shown in FIG. To manufacture.

Then, as shown in FIG. 2C, after the copper foil on the surface of the four-layer substrate 17 is etched to form circuit patterns 13 on both sides, hot pressing and patterning of the prepreg 18 and the copper foil 19 are further performed. By repeating the above steps, a six-layer printed wiring board was manufactured. By the way,
An eight-layer printed wiring board can also be manufactured by adding two layers to the six-layer wiring board by repeating the steps of hot pressing and patterning the prepreg and copper foil.

[0009]

However, in the conventional multilayer printed wiring board having the above-mentioned contents, it is not easy to secure the adhesion state between the core layer and the build-up layer on which the printed wiring is formed, and the circuit pattern is not micron-sized. In the case of high-density wiring formed at a unit wiring pitch, the insulating material may not be completely filled between the wirings, and there is a problem that the so-called “embeddability of the inner layer circuit” of the insulating material is likely to deteriorate. Such a problem is related to the production of a product having non-uniform characteristics such as insulation properties, and leads to a decrease in product yield (reduction in production efficiency) due to the reliability of the printed wiring board and the occurrence of defective products. Also.

As described above, since the embedding property of an inner layer circuit having a high wiring density with an insulating material is uncertain, materials for a multilayer printed wiring board exceeding four layers are collectively laminated and integrated reliably by heat fusion. As a result, it has not been possible to manufacture products with high insulation reliability. In addition, if a liquid insulating material is used, the problem of the embedding of the inner layer circuit is considerably improved, but the coating and drying process of the insulating material takes a long time, and the thin substrate is easily deformed in the drying process. Various problems also occur. Therefore, an object of the invention relating to a multilayer printed wiring board is to solve the above-mentioned problems, and to increase the wiring density of a multilayer printed wiring board laminated and integrated using a heat-fusible film-like insulator. It is an object of the present invention to provide a semiconductor device in which wiring is reliably embedded with an insulating material even when an internal circuit is provided.

Another object of the present invention relating to a method of manufacturing a multilayer printed wiring board is to improve a manufacturing method by build-up of a multilayer printed wiring board using a film-like insulator so that the embedding property of an inner layer circuit of an insulating material is good. An efficient manufacturing method that has high insulation reliability of circuits with a high wiring density and that can be laminated and integrated by a single heat-sealing process in a single heating / pressing step when multiple layers of laminated materials are stacked. It is to provide.

[0012]

Means for Solving the Problems To solve the above problems, the present invention mainly comprises a styrene resin composition having a syndiotactic structure and a thermoplastic resin compatible with the styrene resin composition. As a component, a film-like insulator having a content of the styrene-based resin composition of 35% by weight or more, a double-sided through-hole is formed in the film-like insulator, and a conductive paste is filled in the through-hole. A heat-fusible film for interlayer connection of a laminated electric circuit is formed, a conductor foil is heat-sealed on one or both surfaces of the heat-fusible film for interlayer connection, and a circuit is formed to provide a film-shaped wiring board. A multilayer printed wiring board was obtained by alternately stacking a plurality of laminated materials composed of a film-shaped wiring board and the heat-fusible film for interlayer connection and integrating them by heat-sealing.

The thermoplastic resin forming the film-like insulator in the multilayer printed wiring board has a crystal melting peak temperature of 260 ° C. or higher when measured by differential scanning calorimetry, and a heat of crystal melting. The multilayer printed wiring board was a thermoplastic resin composition in which the relationship between ΔHm and the amount of crystallization heat Hc generated by crystallization during the temperature rise satisfied the relationship represented by the following formula (I).

Formula (I): [(ΔHm−ΔHc) / ΔHm] ≦ 0.4 Alternatively, the thermoplastic resin forming the film-like wiring board in the multilayer printed wiring board has a heat of crystal fusion ΔHm.
The multilayer printed wiring board is a thermoplastic resin composition in which the relationship between the temperature and the amount of heat of crystallization ΔHc generated by crystallization during the temperature rise satisfies the relationship represented by the following formula (II).

Formula (II): [(ΔHm−ΔHc) / ΔHm] ≦ 0.6 Alternatively, the thermoplastic resin forming the multilayer printed wiring board in the multilayer printed wiring board has a heat of crystal fusion ΔHm.
Thus, the multilayer printed wiring board was a thermoplastic resin composition in which the relationship between the temperature and the amount of heat of crystallization ΔHc generated by crystallization during temperature rise satisfied the relationship represented by the following formula (III).

Formula (III): [(ΔHm−ΔHc) / ΔHm] ≧ 0.7 Further, in order to solve the problem relating to the above-described manufacturing method,
In the present invention, a styrene-based resin composition having a syndiotactic structure and a thermoplastic resin compatible with the styrene-based resin composition as main components, and the content of the styrene-based resin composition is 35% by weight or more. Having a crystal melting peak temperature of 260 ° C. or higher measured when the temperature is raised by differential scanning calorimetry, and a heat of crystal fusion ΔHm and a heat of crystallization generated by crystallization during the temperature rise. Δ
A film-like insulator is formed from a thermoplastic resin composition whose relationship with Hc satisfies the relationship represented by the following formula (I), a double-sided through-hole is formed in the film-like insulator, and a conductive material is formed in the through-hole. The paste is filled to form a heat-fusible film for interlayer connection of a laminated electric circuit, and a conductive foil is laminated on one or both surfaces of the heat-fusible film for interlayer connection. After heat-sealing so as to satisfy the relationship shown in II), a circuit is formed on the conductive foil to provide a film-like wiring board, and a laminate comprising the film-like wiring board and the heat-fusible film for interlayer connection is provided. This is a method for manufacturing a multilayer printed wiring board, in which a plurality of materials are alternately stacked, and the thermoplastic resin composition constituting each layer is heat-sealed so as to satisfy a relationship represented by the following formula (III). .

Formula (I): [(ΔHm−ΔHc) / ΔHm] ≦ 0.4 Formula (II): [(ΔHm−ΔHc) / ΔHm] ≦ 0.6 Formula (III): [(ΔHm−ΔHc) /ΔHm]≧0.7 The multilayer printed wiring board of the present invention configured as described above comprises a styrene resin composition having a syndiotactic structure, and a thermoplastic resin compatible with the styrene resin composition. , And sufficiently satisfies the adhesiveness with a conductor foil, heat resistance, mechanical strength, and electrical insulation required for an insulating material for printed circuit boards.

The heat-fusible film for interlayer connection of the laminated electric circuit is formed of the above-mentioned insulating thermoplastic resin material, and the opening of the double-sided through-hole is electrically connected by the conductive paste in the double-sided through-hole. As a contact point, a portion of an electric circuit arranged and formed on one side or both sides of the film is conducted in a layer thickness direction. The thermoplastic resin forming such a film-like insulator or a film-like wiring board has a crystal melting peak temperature of 260 ° C. or more and a heat of crystal melting ΔHm.
And the amount of heat of crystallization ΔHc generated by crystallization during the temperature rise satisfies the relationship represented by the above formula (I) or (II), so that the progress of crystallization is adjusted to an appropriate range. It exhibits excellent adhesive strength by thermal fusion at a relatively low temperature of, for example, less than 250 ° C.
Therefore, multi-layer printed wiring boards having more than four build-up layers can be integrally laminated by heating and pressing. When a conductor foil whose surface is roughened is used as the conductor foil, the adhesive strength is further increased.

Further, the thermoplastic resin composition satisfying the relations represented by the formulas (I) and (II) has a reduced elastic modulus in a bonding temperature region with the conductive foil, and is therefore filled in fine wiring pitches. . Therefore, the embedding property of the inner layer circuit of the multilayer printed wiring board using the heat-fusible film for interlayer connection and the film-like insulator, that is, the insulating property is improved. The method for producing a multilayer printed wiring board according to the present invention is characterized in that a plurality of laminated materials composed of a film-shaped wiring substrate and the heat-fusible film for interlayer connection are alternately laminated, and the heat of crystal fusion of the thermoplastic resin composition constituting each layer is increased. The relationship between ΔHm and the amount of heat of crystallization ΔHc generated by crystallization during heating is expressed by the above formula (III).
Is heat-sealed so as to satisfy the relationship shown by. By doing so, the thermoplastic resin composition after the heat fusion has an insulative property having solder heat resistance to withstand 260 ° C. since the crystallinity of the styrene resin having a syndiotactic structure is appropriately advanced. As a result, the conductive circuit formed by etching the conductive foil is firmly adhered to the film-like insulator, and delamination hardly occurs.

In the above method for producing a multilayer printed wiring board, when a conductor foil is laminated on one side or both sides of a heat-fusible film for interlayer connection and heat-sealed, a crystal of the thermoplastic resin composition after heat-sealing is used. In the method of performing heat fusion so that the relationship between the heat of fusion ΔHm and the heat of crystallization ΔHc generated by crystallization during temperature rise satisfies the relationship represented by the above formula (II), the film-like wiring is again formed after the heat fusion. Even when a plurality of laminated materials composed of a substrate and the heat-fusible film for interlayer connection are alternately stacked, and the heat-sealing is performed by heating and pressing all at once, the thermoplastic resin has an elastic modulus in a bonding temperature region with the conductive foil. Therefore, an appropriate low-viscosity resin is surely filled even in a fine wiring pitch, and a good product having very high embedding property of the inner layer circuit, that is, extremely high insulation reliability can be manufactured. In addition, since the film-like insulator and the conductor foil are bonded by heat without interposing an adhesive such as epoxy resin between the layers, heat resistance,
Various properties such as chemical resistance and electrical properties are not affected by the properties of the adhesive, and the excellent properties of the insulating layer can be fully utilized. Also, since there is no step of applying and drying an adhesive or other liquid laminated material during the manufacturing process, a method of manufacturing a multilayer printed wiring board with high manufacturing efficiency can be achieved.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a multilayer wiring board and a method of manufacturing the same according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 (a1) and (b) or FIG.
) And (b) show two production processes, respectively. The multilayer printed wiring board according to the present invention is obtained by laser processing a film-shaped insulator 1 made of a thermoplastic resin composition having a predetermined composition and thermal characteristics. Holes 2 are formed on both sides of the laminated electric circuit, and a conductive paste 3 is filled in the holes 2 to form a heat-fusible film 4 for interlayer connection of a laminated electric circuit. A conductive foil is heat-sealed on both sides (a1 in FIG. 1) or one side (a2 in FIG. 1) of the film 4 by a vacuum hot press machine, and a conductive circuit 5 is formed by a subtractive method except for unnecessary portions of the conductive foil. Then, a plurality of laminated materials selected from the obtained film-shaped wiring boards 6 and 7 and the heat-fusible film 4 for interlayer connection are laminated, and laminated and integrated by heat fusion.

FIG. 1B shows a multilayer printed wiring board in which conductive circuits 5 are formed in four layers by solid lines.
1) and (b) in FIG.
It is also possible to manufacture a multilayer printed wiring board having multiple layers or more layers. In addition, in order to manufacture a film-shaped insulator, a styrene-based resin having a syndiotactic structure and a thermoplastic resin compatible with the styrene-based resin composition are blended, and a predetermined resin represented by the formula (I) is mixed. Is prepared.

Formula (I): [(ΔHm−ΔHc) / ΔHm] ≦ 0.4 When the conductive foil is thermally fused to the film-like insulator, the glass transition point (Tg) of the thermoplastic resin composition is as follows: Is higher than the crystal melting peak temperature (Tc), that is, a conductor which is heated to a predetermined temperature range in which the amorphousness is maintained, and the thermoplastic resin composition preferably maintains the properties represented by the formula (II). A film-like substrate to which the foil is thermally fused is produced.

Formula (II): [(ΔHm−ΔHc) / ΔHm] ≦ 0.6 As a method of forming a conductive circuit on the conductive foil, a well-known subtractive method can be employed, but an additive method can also be employed. . Incidentally, as a specific example of the subtractive method, a dry film made of an ultraviolet curable resin is laminated on a copper foil, and then a pattern film formed with a cutout mold of a conductive circuit is exposed to ultraviolet light in a state where the pattern film is in close contact with the dry film. Exposure, then remove the pattern film and uncured dry film, perform etching with a ferric chloride solution to remove the copper foil in unnecessary portions of the conductive circuit, and then immerse in a sodium hydroxide solution The remaining dry film on the copper foil is removed to form a conductive circuit. When a plurality of laminated materials comprising a film-shaped wiring board and the heat-fusible film for interlayer connection are laminated and heat-sealed collectively, the heat of crystal fusion ΔHm of the thermoplastic resin composition constituting each layer increases. Thermal fusion is performed so that the relationship with the heat of crystallization ΔHc generated by crystallization during warming satisfies the relationship represented by the formula (III).

Formula (III): [(ΔHm−ΔHc) / ΔHm] ≧ 0.7 In this manner, the thermoplastic resin composition is heated to a temperature near the crystal melting peak temperature (Tc) (for example, 230 to 250 ° C.). As a result, reliable heat fusion becomes possible and crystallization of the thermoplastic resin composition proceeds, so that a multilayer printed wiring board having excellent solder heat resistance can be manufactured.

In the present invention, the styrene resin having a syndiotactic structure, which is the first component constituting the film-like insulator, has a stereochemical structure having a syndiotactic structure, that is, a main chain formed from CC bonds. Against
It has a three-dimensional structure in which phenyl groups and substituted phenyl groups, which are side chains, are alternately located in opposite directions. The content of the styrene resin is preferably 35% by weight or more and 35 to 70% by weight of the film-like insulator, and 35% by weight.
If it is less than 70% by weight, the solder heat resistance tends to be poor, and if it exceeds 70% by weight, the adhesion to the conductor foil tends to be poor.

The thermoplastic resin compatible with the styrene resin as the second component constituting the film-shaped insulator may be any resin that can be uniformly dispersed at the time of melt molding. And polystyrene-based, polyester-based, polyamide-based, polyphenylene ether-based, and polyphenylene sulfide-based resins, but are not limited thereto. In the present invention, a modified polyphenylene ether (modified PPE) is preferably used. The content of the thermoplastic resin compatible with the styrene resin is preferably in the range of 30 to 65% by weight of the film-like insulator, and if it is less than 30% by weight, the adhesiveness to the conductor foil tends to be poor. If it exceeds 65% by weight, the solder heat resistance tends to be poor.

The film-like insulator may further contain a rubber-like elastic body for the purpose of improving mechanical strength in addition to the above-mentioned components. As the rubber-like elastic body, a styrene-butadiene block copolymer ( SBR), hydrogenated styrene-butadiene block copolymer (SEB), styrene-
Examples include butadiene-styrene block copolymer (SBS) and hydrogenated styrene-butadiene-styrene block copolymer (SEBS), but are not limited thereto. In the present invention, SEBS is preferably used among the rubbery elastic bodies. The rubber-like elastic body is preferably contained in the range of 10 to 20% by weight of the film-like insulator, and if less than 10% by weight, the effect of improving the strength is small, and if it exceeds 20% by weight, the heat resistance tends to decrease. is there.

The thermal characteristics of the film-like insulator, which is an important controlling factor in the present invention, are as follows. The relationship between the heat of crystal fusion ΔHm and the heat of crystallization ΔHc generated by crystallization during heating is expressed by the following formula (I). It is to satisfy the relationship shown.

The thermal characteristic represented by the formula (I): [(ΔHm−ΔHc) / ΔHm] ≦ 0.4 (ΔHm−ΔHc) / ΔHm is expressed by JI
The measured values of two heats of transition appearing on the DSC curve when the temperature is raised by differential scanning calorimetry according to S K 7121 and JIS K 7122, the heat of crystal fusion ΔHm (J / g) and the heat of crystallization ΔHc (J / g) Is calculated from the value of

The value of the formula (ΔHm−ΔHc) / ΔHm also depends on the type and molecular weight of the raw material polymer and the compounding ratio of the composition, but greatly affects the molding and processing conditions of the film-shaped insulator. I do. That is, when the film is formed into a film, the raw material polymer is melted and then cooled immediately, whereby the value of the above formula can be reduced.
Further, these numerical values can be controlled by adjusting the heat history in each step. The heat history here refers to the temperature of the film-shaped insulator and the time during which the temperature has been reached, and the higher the temperature, the larger the numerical value tends to be. Regarding the thermal characteristics of the conductor foil and the film-like insulator before thermal fusion, it is preferable that the value represented by the above formula (I) is as small as possible. 0.
If it exceeds 4, the crystallinity is already high, and the crystallization further proceeds during the heat-sealing for multi-layering, and the adhesive strength is undesirably reduced. The relationship represented by the above formula (II) is based on the measurement after heat bonding in a copper-clad laminate in which a conductor foil is heat-bonded to at least one surface of a film-like insulator in a process of manufacturing a multilayer printed wiring board. It is.

When the value represented by the formula (II) exceeds 0.6, the crystallinity is already high, and the crystallization is further advanced during the heat-sealing for multilayering, whereby the adhesive strength is reduced. Further, it is necessary to perform heat fusion with the conductor foil at a high temperature, which is not preferable in terms of manufacturing efficiency. Then, the thermal characteristics of the film-like insulator after thermal bonding after multilayering satisfy the relationship of the following formula (III). Formula (III): [(ΔHm−ΔHc) / ΔHm] ≧ 0.7 Because, when the value of the above formula (III) is as low as less than 0.7, crystallization of the insulating layer is insufficient, and This is because heat resistance (usually 260 ° C.) cannot be maintained.

The film-like insulator used in the present invention usually has a thickness of 25 to 300 μm, and its production method is, for example, a known film-forming method such as an extrusion casting method using a T-die or a calendering method. What is necessary is just to employ | adopt and it is not necessary to employ | adopt a manufacturing method especially limited. In addition, it is preferable to employ the extrusion casting method using a T-die from the viewpoint of film forming property and stable productivity. The molding temperature of the extrusion casting method is appropriately adjusted depending on the flow characteristics and film forming characteristics of the composition, but is generally from the melting point of the composition to 430 ° C. or less.

The resin composition constituting the film-shaped insulator used in the present invention may contain other resins and other additives to such an extent that the effects of the present invention are not impaired. Examples include a heat stabilizer, an ultraviolet absorber, a light stabilizer, a colorant, a lubricant, a flame retardant, and an inorganic filler.
Further, the surface of the film-shaped insulator may be subjected to embossing or corona treatment for improving the handling properties and the like. As the conductive foil used in the present invention, for example, copper, gold,
8 ~ thick like silver, aluminum, nickel, tin etc.
A metal foil of about 70 μm is used. Among them, the metal foil to be applied is particularly preferably a copper foil whose surface has been subjected to a chemical conversion treatment such as a black oxidation treatment. It is preferable to use a conductive foil whose contact surface (overlapping surface) with the film-shaped insulator has been chemically or mechanically roughened in advance in order to enhance the adhesive effect. Specific examples of the conductor foil subjected to the surface roughening treatment include a roughened copper foil that has been electrochemically treated when producing an electrolytic copper foil.

When the conductor foil is superimposed on one or both surfaces of the film-shaped insulator and heat-sealed under heating and pressing conditions, for example, a hot pressing method or a heat laminating roll method, a method combining these, or other well-known methods Can be adopted. Here, in the case of multilayering, the layer thickness of the insulator on the film is 2 times the total thickness of the conductor foil.
It is desirable that the number be twice or more. If it is less than twice, the resin embedding property into the conductor circuit portion tends to be insufficient at the time of multilayering.

[0037]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the production methods of Production Examples 1 to 3 of the film insulator satisfying the conditions of the film insulation of the present invention and the production methods of Reference Examples 1 and 2 and the physical properties thereof will be described below. .

[Production Example 1 of Film Insulator] A sterene resin having a syndiotactic structure (Zarek, manufactured by Idemitsu Petrochemical Co., Ltd.) (abbreviated as SPS in the following text or in Tables 1 and 2). 60% by weight and modified PPE
(Mitsubishi Engineering Plastics: Iupies) 40% by weight was dry blended. This mixed composition was extruded to produce a film insulator having a thickness of 25 μm.

[Production Example 2 of Film Insulator] A film insulation was produced in the same manner as in Production Example 1 except that the mixing ratio of the mixed composition was 40% by weight of SPS and 60% by weight of modified PPE. did.

[Production Example 3 of Film Insulator] Production Example 1
In, the mixture ratio of the mixed composition is SPS 30% by weight,
A film-like insulator was produced in the same manner except that the modified PPE was 70% by weight.

[Reference Examples 1 and 2 of Film Insulator] Except that in Preparation Example 1, the mixture ratio of the mixed composition was 100% by weight of SPS (Reference Example 1) or 100% by weight of modified PPE (Reference Example 2). Manufactured the respective film-shaped insulators in the same manner.

In order to examine the physical properties of the film-like insulators obtained in the above Production Examples and Reference Examples, the following items (1) and (2) were measured or calculated from the measured values. These results are summarized in Table 1.

(1) Glass transition temperature (° C.), crystallization temperature (° C.), crystal melting peak temperature (° C.) JIS K712
According to 1, a 10 mg sample was used, and the above-mentioned respective temperatures when the heating rate was increased at a rate of 10 ° C./min using Perkin Elmer: DSC-7 were determined from thermograms.

(2) (ΔHm−ΔHc) / ΔHm According to JIS K7122, 10 mg of a sample was used, and the heating rate was set to 1 using DSC-7 manufactured by PerkinElmer.
The heat of crystal fusion ΔHm (J / g) and the heat of crystallization ΔHc (J / g) were determined from the thermogram when the temperature was raised at 0 ° C./min, and the value of the above equation was calculated.

[0045]

[Table 1]

Example 1 Thickness 25 obtained in Production Example 1
Inner via with laser on μm film insulator
Making holes for holes and using a screen printing machine
The hole was filled with a conductive paste. This conductive page
After thoroughly drying the strike, apply it on both sides of the film insulator.
Electrochemically roughened copper foil with a thickness of 12 μm
And pressing at 760 mmHg in a vacuum atmosphere at a pressing temperature of 2
00 ° C, press pressure 30kg / cm ^Two, Press time 10
For 2 minutes to produce a double-sided copper-clad laminate. Production
For the film-like insulator of the double-sided copper-clad laminate,
(2) The measurement test of (ΔHm−ΔHc) / ΔHm
The results are shown in Table 2. In addition,
The double-sided copper-clad laminate obtained by the method (3) described later.
The adhesive strength was examined, and the results are shown in Table 2.

A circuit pattern was formed on the obtained double-sided copper-clad laminate by a subtractive method, and two wiring boards were formed by etching a conductive circuit. The thickness 2 obtained in Production Example 1 between the two wiring boards
Stacked in a state shown in FIG. 1 (a1) with a 5 μm film-shaped insulator interposed therebetween, and under a vacuum atmosphere at 760 mmHg, a press temperature of 220 ° C., a press pressure of 30 kg / cm ² , and a press time of 20 minutes by a pin lamination method. Then, a multilayer printed wiring board having four layers was manufactured. With respect to the obtained multilayer printed wiring board, the above (2) (ΔHm−ΔH
c) In addition to conducting a measurement test of / ΔHm, the adhesive strength between the copper foil circuit and the film-like insulator at room temperature is checked by the following test method (3), and the presence or absence of delamination is checked by a scanning electron microscope (described below). (Method (5)), and the solder heat resistance was examined by the following test method (4). The results are shown in Table 2.

(3) Adhesive strength The peel strength of the copper foil of the FPC blank was measured in accordance with the normal peel strength of JIS C6481, and the average value was shown in kgf / cm.

(4) Solder heat resistance According to the normal solder heat resistance of JIS C6481,
After floating in a solder bath at 60 ° C. for 10 seconds with the copper foil side of the test piece in contact with the solder bath, take out from the bath and allow it to cool to room temperature, and visually observe the presence or absence of swelling or peeling,
The quality was evaluated.

(5) The multilayer printed wiring board is embedded in epoxy resin, a sample for section observation is prepared by a precision cutting machine, and the cut surface is observed by a scanning electron microscope (SEM). The presence or absence of delamination with the conductive circuit made of foil was evaluated.

[0051]

[Table 2]

Example 2 In Example 1, using Production Example 2 as a film-like insulator, the press temperature for producing a double-sided copper-clad laminate was 225 ° C., and the heat for producing a four-layer substrate was A four-layer printed wiring board was prepared in the same manner as in Example 1 except that the pressing conditions were changed to a temperature of 240 ° C. and a breath time to 30 minutes, and the evaluations of tests (3) to (5) were evaluated in Table 2.
Also described in the inside.

Example 3 In Example 1, five circuit boards were formed in which a circuit pattern was formed from a double-sided copper-clad laminate, and a conductive circuit was formed by etching. A 10-layer multilayer printed wiring board was manufactured in the same manner as in Example 1, except that the obtained film-shaped insulators were stacked and stacked and heat-sealed at once by a pin lamination method.

Comparative Example 1 A four-layer multilayer printed wiring board was produced in the same manner as in Example 1, except that the pressing temperature for producing the double-sided copper-clad laminate was 215 ° C. Table 2 also shows the evaluations of tests (3) to (5) for this.

Comparative Example 2 The procedure of Example 2 was repeated except that the pressing temperature of the four-layered multilayer printed wiring board was changed to 230 ° C. and the pressing time was changed to 10 minutes.
A multi-layer printed wiring board was prepared and tested (3) to (5).
Are also shown in Table 2.

[Comparative Example 3] In Example 1, the production temperature was changed to 240 ° C and the press time was changed to 20 minutes in the production of the double-sided copper-clad laminate using Production Example 3 as the film-like insulator. Except for the above, a four-layer multilayer printed wiring board was produced in the same manner as in Example 1, and tests (3) to
The evaluation of (5) is also shown in Table 2.

As is clear from the results in Table 2, the adhesive strength of the double-sided copper-clad laminate of Example 1 was 0.7 kgf / 10
cm, which is (ΔHm−ΔHc) / ΔH
The value of m was also an appropriate value of 0.31. The value of (ΔHm−ΔHc) / ΔHm at the time of laminating the four-layered multilayer printed wiring board is also an appropriate value of 0.96, and the adhesive strength is 1.5 kgf /
It was a good value of 10 cm. In the results of the solder heat resistance test, no swelling or peeling was observed on the substrate, and no delamination was observed at all by SEM observation of the four-layered multilayer printed wiring board, and the resin wrapped around the circuit pattern (filling). Amount) was good, and generation of voids was not observed at all.

The adhesive strength of the double-sided copper-clad laminate of Example 2 was also a good value of 1.3 kgf / 10 cm, the results of the solder heat resistance test were good, and the SEM after four-layer heat fusion was performed.
No delamination was observed at all, and the resin wrapping around the circuit pattern was good.

Also in Example 3, the adhesive strength was a good value, and the results of the solder heat resistance test showed that no swelling or peeling was observed on the substrate, and the SEM of the 10-layer multilayer printed wiring board was not observed.
No delamination was observed at all, and the wraparound (filling amount) of the resin in the vicinity of the circuit pattern was good, and no generation of voids was observed. Compared with the conventional method of manufacturing a build-up type multilayer printed wiring board, the number of steps is considerably smaller, and the number of manufacturing days and manufacturing cost can be reduced. Furthermore, since the quality of the substrate can be determined at the stage of the double-sided copper-clad laminate before the multilayer press, the yield is greatly improved. On the other hand, the four-layer printed wiring board of Comparative Example 1
The adhesion between the layers was insufficient, and the solder heat resistance was poor, with swelling and peeling observed.

The four-layer printed wiring board of Comparative Example 2
Although there was adhesion between the layers, the solder heat resistance was poor. In Comparative Example 3, the adhesive strength between the copper foil and the film of the double-sided copper-clad laminate was a low value of 0.2 kgf / 10 cm,
The circuit peeled off in the etching step.

[0061]

As described above, the multilayer printed wiring board of the present invention comprises a styrene resin composition having a predetermined syndiotactic structure and a thermoplastic resin compatible with the styrene resin composition. A predetermined amount is blended to form a film-like insulator with a crystalline thermoplastic resin composition having a predetermined thermal property, and the film-like insulator is used to form a heat-fusible film for interlayer connection of a laminated electric circuit. Since a film-like wiring board with a circuit formed on it is formed, and a plurality of these are laminated and integrated by heat fusion, the thermoplastic resin composition of each layer exhibits excellent adhesive strength when melted by heating. Even in a multilayer printed wiring board having more than four layers, there is no delamination between layers, and the thermoplastic resin composition exhibits the required solder heat resistance due to the heat resistance.

The thermoplastic resin composition that satisfies the relationship represented by the formula (I) has a reduced elastic modulus in a bonding temperature region with the conductive foil, so that even when the layers are thermally fused, fine wiring pitches can be obtained. A multilayer printed wiring board with good insulation properties of an inner layer circuit formed with a high wiring density filled with an insulating material. The method for manufacturing a multilayer printed wiring board of the present invention is a method for manufacturing a multilayer printed wiring board using a film-like insulator made of a crystalline thermoplastic resin having predetermined thermal characteristics. The embedding property for the inner layer circuit is improved, and the circuit with high insulation reliability can be manufactured.Furthermore, when the laminated material is laminated in multiple layers, it can be laminated and integrated by heat fusion in a single heating and pressurizing process. There is an advantage that it is a good manufacturing method.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a manufacturing process of a multilayer printed wiring board.

FIG. 2 is a schematic view showing a manufacturing process of a conventional multilayer printed wiring board.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Film-shaped insulator 2 Holes 3, 12 Conductive paste 4 Heat-fusible film for interlayer connection 5 Conductive circuit 6, 7 Film-shaped wiring board 11 Preparatory hole 13 Circuit pattern 14 Double-sided wiring board 15, 18 Pre-preg 16, 19 Copper foil 17 4-layer board

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5E346 AA06 AA12 AA15 AA26 AA43 BB01 CC08 CC31 DD02 DD12 DD32 EE02 EE06 EE08 EE19 FF18 FF35 GG02 GG15 GG27 GG28 HH11 HH18

Claims (7)

[Claims] 1. A styrenic resin composition having a syndiotactic structure, and a thermoplastic resin compatible with the styrenic resin composition as a main component, wherein the content of the styrenic resin composition is 35% by weight. The above-mentioned film-shaped insulator, a heat-fusible film for interlayer connection of a laminated electric circuit is formed by forming a double-sided through hole in the film-shaped insulator and filling a conductive paste in the through-hole, A film-like wiring board is provided by heat-sealing a conductor foil on one or both surfaces of the interlayer-bonding heat-fusible film and forming a circuit, and comprises the film-like wiring board and the interlayer-bonding heat-fusible film. A multilayer printed wiring board in which a plurality of laminated materials are alternately stacked and integrated by heat fusion. 2. The multilayer printed wiring board according to claim 1, wherein the conductor foil is a surface-roughened conductor foil. 3. The thermoplastic resin forming the film-like insulator has a crystal melting peak temperature measured at 260 ° C. or higher when heated by differential scanning calorimetry, and has a crystal melting heat amount ΔHm and Heat of crystallization Δ generated by crystallization
The multilayer printed wiring board according to any one of claims 1 to 2, wherein the thermoplastic resin composition has a relationship with Hc satisfying a relationship represented by the following formula (I). Formula (I): [(ΔHm−ΔHc) / ΔHm] ≦ 0.4 4. The relationship between the heat of crystal fusion ΔHm and the heat of crystallization ΔHc generated by crystallization during temperature rise of the thermoplastic resin forming the film-like wiring board is represented by the following formula (II). The multilayer printed wiring board according to claim 1, which is a thermoplastic resin composition that satisfies the conditions. Formula (II): [(ΔHm−ΔHc) / ΔHm] ≦ 0.6 5. The relationship between the heat of crystal fusion ΔHm of the thermoplastic resin forming the multilayer printed wiring board and the heat of crystallization ΔHc generated by crystallization during heating is represented by the following formula (III).
The multilayer printed wiring board according to any one of claims 1 to 2, wherein the thermoplastic resin composition satisfies the following relationship. Formula (III): [(ΔHm−ΔHc) / ΔHm] ≧ 0.7 6. A styrenic resin composition having a syndiotactic structure, and a thermoplastic resin compatible with the styrenic resin composition as a main component, wherein the content of the styrenic resin composition is 35% by weight. The above film insulator, having a crystal melting peak temperature of 260 ° C. or more measured when the temperature is raised by differential scanning calorimetry, and a crystal melting heat ΔHm and crystallization caused by crystallization during the temperature rise. Calorie Δ
A film-like insulator is formed from a thermoplastic resin composition whose relationship with Hc satisfies the relationship represented by the following formula (I), a double-sided through-hole is formed in the film-like insulator, and a conductive material is formed in the through-hole. The paste is filled to form a heat-fusible film for interlayer connection of a laminated electric circuit, and a conductive foil is laminated on one or both surfaces of the heat-fusible film for interlayer connection. After heat-sealing so as to satisfy the relationship shown in II), a circuit is formed on the conductive foil to provide a film-like wiring board, and a laminate comprising the film-like wiring board and the heat-fusible film for interlayer connection is provided. A method of manufacturing a multilayer printed wiring board, comprising a plurality of materials alternately stacked and heat-sealed so that a thermoplastic resin composition constituting each layer satisfies a relationship represented by the following formula (III). Formula (I): [(ΔHm−ΔHc) / ΔHm] ≦ 0.4 Formula (II): [(ΔHm−ΔHc) / ΔHm] ≦ 0.6 Formula (III): [(ΔHm−ΔHc) / ΔHm] ≧ 0.7 7. The method for producing a multilayer printed wiring board according to claim 6, wherein the conductor foil to be laminated on one or both surfaces of the heat-fusible film for interlayer connection is a conductor foil having a roughened surface.