JP4892817B2 - Insulating resin layer, insulating resin layer with carrier, and multilayer printed wiring board - Google Patents

Description

  The present invention relates to an insulating resin layer, an insulating resin layer with a carrier, and a multilayer printed wiring board.

As the capacity, speed, density, and miniaturization of electronic devices in recent years have progressed, a method of surface-mounting a component having a plurality of functions on a single package substrate is often used.
However, the method of mounting components on the surface of the package substrate is limited to making the area of the substrate smaller than the area of the component to be mounted because of the space in the two-dimensional direction. There was a limit.

  In view of this, a method has been devised in which each component is incorporated not only on the surface of the package substrate but also inside the substrate and arranged three-dimensionally to reduce the size and density of the package substrate.

  In a board with a built-in component, it is necessary to increase the signal propagation speed as the frequency of the component increases. To achieve this, a low dielectric constant, a low dielectric loss tangent, and a low water absorption rate are required. An insulating resin layer having such characteristics is required.

Such an object is achieved by the following present inventions (1) to (5).
(1) An insulating resin layer used for a multilayer printed wiring board, wherein the insulating resin layer includes a benzocyclobutene resin and / or a prepolymer thereof and an inorganic filler, and has a relative dielectric constant of 3.2 or less . A resin composition comprising a certain first layer and a second layer containing a cyanate resin and / or a prepolymer thereof and an inorganic filler and having a linear expansion coefficient of 40 ppm / ° C. or less , and forming the first layer The product contains 30 to 90% by weight of the benzocyclobutene resin and / or its prepolymer with respect to the total solid content in the resin composition forming the first layer, and the resin composition forming the second layer is comprises 10 to 50% by weight relative to the total solid content of the resin composition forming the second layer of the cyanate resin and / or a prepolymer thereof, and laminated on at least one layer respectively, wherein the benzocyclobutene resin Insulating resin layer, wherein the number-average molecular weight is 3000～1,000,000.
(2) The insulating resin layer according to (1), wherein the first layer has a water absorption rate of 0.8% by weight or less.
(3) An insulating resin layer with a carrier comprising the insulating resin layer according to (1) or (2) above and a carrier bonded to at least one surface thereof.
(4) A multilayer printed wiring board obtained by laminating the insulating resin layer according to (1) or (2) above on at least one surface of an inner layer circuit board, and heating and pressing.
(5) A multilayer printed wiring board obtained by laminating the insulating resin layer with a carrier as described in (3) above on at least one surface of an inner layer circuit board, and heating and pressing.

Mechanical strength such as low linear expansion and high tensile strength is required to prevent cracks generated during the cooling and heating cycle. In order to obtain these mechanical strengths, for example, there is a method using a resin composition highly filled with an inorganic filler (see, for example, Patent Document 2). When a resin composition highly filled with an inorganic filler is used, the linear expansion can be reduced and the tensile strength can be increased. Therefore, the stress during the cooling and heating cycle is relieved and the occurrence of cracks can be prevented.
However, when the resin is highly filled with an inorganic filler, the dielectric constant increases, which affects the signal propagation speed, which is important for high frequency applications.

Further, cyanate resin is used as a resin having a low linear expansion coefficient and excellent mechanical strength. The cyanate resin forms a triazine ring by its curing reaction. Since the triazine ring is rigid due to its skeletal structure, the volume change upon heating is small and the mechanical strength is excellent.
However, the triazine ring has a high water absorption rate due to the presence of a lone pair of electrons in the nitrogen atom in the ring, and also has a relative dielectric constant and dielectric loss tangent that are important in high frequency applications under acidic conditions, particularly high-temperature and high-humidity conditions. There is concern about deterioration.

  As described above, there is a need for an insulating resin layer material that can be used for a multilayer printed wiring board with built-in components and that has sufficient mechanical characteristics and dielectric characteristics in response to miniaturization and high density of package substrates. It was.

Japanese Patent Laid-Open No. 2000-21872 Japanese Patent Laid-Open No. 11-220262

  The present invention provides an insulating resin layer having high mechanical strength and excellent dielectric characteristics, an insulating resin layer with a carrier, and a multilayer printed wiring board using these.

Such an object is achieved by the present inventions (1) to ( 5 ) below.
(1) An insulating resin layer used for a multilayer printed wiring board, wherein the insulating resin layer includes a first layer containing a benzocyclobutene resin and / or a prepolymer thereof , a cyanate resin and / or the same consists of a second layer are those comprising a prepolymer, laminated on at least one layer respectively, the insulating resin layer has a number average molecular weight, wherein 3000～1,000,000 der Rukoto of the benzocyclobutene resin .
(2) The insulating resin layer according to (1), wherein the first layer has a water absorption rate of 0.8% by weight or less.
(3) An insulating resin layer with a carrier comprising the insulating resin layer according to (1) or (2 ) above and a carrier bonded to at least one surface thereof.
(4) A multilayer printed wiring board obtained by laminating the insulating resin layer according to (1) or (2 ) above on at least one surface of an inner layer circuit board, and heating and pressing.
(5) A multilayer printed wiring board obtained by laminating the insulating resin layer with a carrier as described in (3 ) above on at least one surface of an inner layer circuit board, and heating and pressing.

  The present invention relates to an insulating resin layer composed of at least one of a resin layer having excellent dielectric properties and a resin layer having excellent mechanical properties, an insulating resin layer with a carrier, and a multilayer printed wiring board using them. Thus, it is possible to manufacture a multilayer printed wiring board with improved mechanical strength around the component without impairing the dielectric characteristics around the high frequency circuit as compared with the conventional one.

Hereinafter, the insulating resin layer, the insulating resin layer with carrier, and the multilayer printed wiring board of the present invention will be described.
The insulating resin layer of the present invention comprises a first layer having a relative dielectric constant of 3.2 or less and a second layer having a linear expansion coefficient of 40 ppm or less, and each layer is laminated at least one layer. Features.
Moreover, the insulating resin layer with a carrier of the present invention is composed of the insulating resin layer of the present invention and a carrier bonded to at least one surface thereof.
The multilayer printed wiring board of the present invention is characterized in that the insulating resin layer of the present invention or the insulating resin layer with a carrier is laminated on at least one surface of the inner circuit board, and heated and pressed.

First, the insulating resin layer of the present invention will be described.
In the insulating resin layer of the present invention, the first layer has a relative dielectric constant of 3.2 or less. The water absorption rate of the first layer is not particularly limited, but is preferably 0.8% by weight or less. As a result, the relative permittivity and dielectric loss tangent, which are important in a high-frequency circuit, can be lowered even under high-temperature and high-humidity conditions, and a decrease in connection reliability can be suppressed.

Although it does not specifically limit as a resin composition which can form such a 1st layer, It is preferable that it contains a benzocyclobutene resin and / or its prepolymer.

  The benzocyclobutene resin used in the present invention is not particularly limited as long as it contains a cyclobutene skeleton. Among these, it is preferable to include a benzocyclobutene resin represented by the following general formula (I). Thereby, a glass transition temperature can be made high and the resin characteristic after hardening can be improved.

  Since the benzocyclobutene resin does not generate a functional group having a large polarizability such as a hydroxyl group by a curing reaction, the dielectric property is very excellent and the water absorption is low. Furthermore, since it has a rigid chemical structure, it has excellent heat resistance.

  Further, a B-staged benzocyclobutene resin having the above general formula (I) (prepolymer) is also preferably used for adjusting moldability and fluidity, and is included in the present invention. B-staging is usually performed by heating and melting a benzocyclobutene resin. Here, the B-staged benzocyclobutene resin is, for example, one having a number average molecular weight of 3000 to 1,000,000. The number average molecular weight can be measured using, for example, GPC.

  In the case where a benzocyclobutene resin is used in the resin composition forming the first layer, the content of the benzocyclobutene resin in the resin composition is not particularly limited, but it is 20 to the total solid content in the resin composition. 95 weight% is preferable, and 30 to 90 weight% is especially preferable. If the content is less than the above lower limit, the effect of improving the dielectric properties such as relative permittivity and dielectric loss tangent may not be sufficient, and if the content exceeds the upper limit, the mechanical strength may be lowered.

  In the insulating resin layer of the present invention, the second layer has a linear expansion coefficient of 40 ppm or less. Further, the tensile strength of the second layer is not particularly limited, but is preferably 80 MPa or more. As a result, the mechanical strain generated when a thermal cycle load is applied can be alleviated, and the thermal reliability can be improved by suppressing cracks generated in a resin near the metal such as a chip or a copper wiring.

  Although it does not specifically limit as a resin composition which can form such a 2nd layer, It is preferable that it contains cyanate resin and / or its prepolymer.

  The cyanate resin is not particularly limited, and may be a resin having a cyanate group. Among these, it is preferable to contain novolak cyanate resin represented by the following general formula (II). Thereby, a glass transition temperature can be made high and the mechanical strength and flame retardance after hardening can be improved more.

  The cyanate resin forms a triazine ring by a curing reaction, and is excellent in heat resistance due to its rigid skeleton structure, and has a small volume change during heat and excellent mechanical strength.

The number average molecular weight of the novolak cyanate resin represented by the general formula (II) is not particularly limited, but is preferably 250 to 900, and particularly preferably 300 to 600. When the number average molecular weight of the novolak-type cyanate resin is less than the above lower limit value, the mechanical strength may be lowered, and when the upper limit value is exceeded, the curing rate of the resin composition is high, and the storability may be lowered.
The novolac type cyanate resin can be obtained, for example, by reacting an arbitrary novolac type phenol resin with a halogenated cyanide compound such as cyanogen chloride or cyanogen bromide.

  When the cyanate resin is used in the resin composition forming the second layer, the content of the cyanate resin in the resin composition is not particularly limited, but is preferably 5 to 60% by weight of the total solid content in the resin composition, 10 to 50 weight% is especially preferable. If the content is less than the lower limit, the effect of improving the mechanical strength may be reduced. If the content exceeds the upper limit, the water absorption is increased, and the dielectric properties in the high frequency region may be reduced.

In the present invention, the relative dielectric constant, water absorption, linear expansion coefficient, and tensile strength are measured under the following conditions.
(1) Relative permittivity: Measured under the condition of A state according to JIS C 6481.
(2) Water absorption: Measured under the conditions of E-24 / 50 + D-24 / 23 according to JIS C 6481.
(3) Linear expansion coefficient: R10 ° C, measured between 35 ° C and 85 ° C.
(4) Tensile strength: in load mode, load full scale 20kgf, speed 5mm / min. It measured on condition of this.

  In the insulating resin layer of the present invention, each of the resin compositions forming the first layer and the second layer can contain a curing agent.

  Although it does not specifically limit as a hardening | curing agent used with the resin composition which forms a 1st layer, When using a benzocyclobutene resin, as a compound which has an effect | action equivalent to the hardening | curing agent or a hardening | curing agent, for example, triallyl Isocyanurate, polybutadiene rubber, compounds having an olefin functional group such as SBR, NBR, ABS, compounds having an acrylic functional group such as acrylate ester, compounds having a methacrylic functional group such as MMA, 1,2-bis (Azidobenzyl) A compound having an azide group such as ethylene can be mentioned.

  Further, the curing agent used in the resin composition for forming the second layer is not particularly limited, but when a cyanate resin is used, as the curing agent or a compound having an action equivalent to that of the curing agent, 2-phenyl Imidazole compounds such as -4-methyl-5-hydroxymethylimidazole, 2-phenyl-4-methylimidazole, 2-methylimidazole, 1-benzyl-2-methylimidazole, 2-phenyl-4,5-dihydrobank methylimidazole In addition, tris (acetylacetonato) cobalt (III), novolac type phenol resin and the like can be mentioned.

The blending amount of the curing agent is not particularly limited, but when a benzocyclobutene resin is used in the resin composition forming the first layer, it may be 0.1 to 5% by weight with respect to the benzocyclobutene resin. The amount is particularly preferably 1 to 4% by weight.
Moreover, when using cyanate resin with the resin composition which forms a 2nd layer, it is preferable to set it as 0.01 to 1 weight% with respect to cyanate resin, for example with an imidazole compound, Most preferably, it is 0.02 to 0 .8% by weight. Moreover, in a novolak-type phenol resin, it is preferable to set it as 1-10 weight% with respect to cyanate resin, Most preferably, it is 2-8 weight%.

In the resin composition forming the first layer, when the amount of the curing agent is less than the lower limit, when producing a multilayer printed wiring board, the flow at the time of heat and pressure molding becomes large, and the insulating resin layer Smoothness may be reduced. Moreover, when the said upper limit is exceeded, a shaping | molding defect may arise in a multilayer printed wiring board.
In the resin composition forming the second layer, if the blending amount of the curing agent is less than the above lower limit value, the flow at the time of heat and pressure molding increases, resulting in variations in the insulating layer thickness, or by heating. The multilayer printed wiring board may become slippery during pressure forming. Moreover, when the said upper limit is exceeded, a shaping | molding defect may arise in a multilayer printed wiring board.

In the resin composition forming the insulating resin layer of the present invention, an inorganic filler can be used for both the first layer and the second layer.
The inorganic filler used here is not particularly limited, but for example, nitrides such as aluminum nitride, boron nitride, and silicon nitride, talc, fired clay, unfired clay, mica, silicates such as glass, titanium oxide, Oxides such as alumina, silica and fused silica, carbonates such as calcium carbonate, magnesium carbonate and hydrotalcite, hydroxides such as aluminum hydroxide, magnesium hydroxide and calcium hydroxide, barium sulfate, calcium sulfate and calcium sulfite And borates such as zinc borate, barium metaborate, aluminum borate, calcium borate, sodium borate and the like.

Among these, silica with low thermal expansion and high insulation reliability is preferable. Furthermore, spherical silica is preferable, and spherical fused silica is particularly preferable. Thereby, the compounding quantity of the inorganic filler in a resin composition can be increased, and an insulating resin layer can be made especially low thermal expansion. Moreover, since the melt viscosity of the resin composition can be kept low by using spherical silica, it is possible to improve the moldability for filling the irregularities of the inner circuit board when manufacturing the multilayer printed wiring board.

  Although it does not specifically limit as a particle size of the said inorganic filler, It is preferable that an average particle diameter is 0.01-5 micrometers, More preferably, it is 0.2-2 micrometers. When the average particle size is less than the above lower limit, the viscosity may increase when a resin composition varnish is prepared. Moreover, when the said upper limit is exceeded, sedimentation etc. of an inorganic filler will occur easily in a resin composition varnish, and workability | operativity may fall in any case.

  In addition to the components described above, the resin composition used in the insulating resin layer of the present invention is not limited to the purpose of the present invention, but other thermosetting resins, thermoplastic resins, flame retardants, and curing accelerators. Agents, coupling agents, and other components can be added.

  The insulating resin layer of the present invention has a first layer and a second layer composed of such a resin composition. Thereby, at the time of manufacturing a multilayer printed wiring board, it is possible to achieve both the embedding property of the unevenness of the inner layer circuit and the mounted component, the maintenance of the insulating layer thickness, and smoothing.

  In the insulating sheet of the present invention, the thicknesses of the first layer and the second layer are not particularly limited, but the first layer is preferably 10 to 50 μm, and the second layer is preferably 10 to 100 μm. Moreover, although it does not specifically limit as thickness of the whole insulating sheet, It is preferable to set it as 20-100 micrometers.

The insulating resin layer of the present invention is composed of the first layer and the second layer described above, and one or more layers are laminated.
Although it does not specifically limit as a structure of the insulating resin layer of this invention, For example, the 1st layer and the 2nd layer can be joined one layer at a time, and it can be set as the insulating resin layer of this invention. Further, two or more of the first layer and / or the second layer may be bonded to form the insulating resin layer of the present invention.

Next, the insulating resin layer with a carrier of the present invention will be described.
The insulating resin layer with a carrier of the present invention is composed of the above-described insulating resin layer of the present invention and a carrier bonded to at least one surface thereof.

  The carrier is not particularly limited, but for example, a metal foil composed of copper or a copper alloy, aluminum or an aluminum alloy, a fluorine resin, a polyimide resin, a polybutylene terephthalate, or a polyester resin such as polyethylene terephthalate. Resin film and the like.

In the insulating resin layer with a carrier of the present invention, the positional relationship between the carrier and the insulating resin layer is not particularly limited. For example, the insulating resin layer is composed of one layer each of the first layer and the second layer. In the case where the first layer is formed, the first layer is preferably formed on the side to be bonded to the carrier. And it is preferable that a 2nd layer is formed in the opposite side to the side joined to the said carrier of a 1st layer.
Thereby, when manufacturing a multilayer printed wiring board using the insulating resin layer with a carrier of the present invention, the insulating resin layer side of the insulating resin layer with a carrier is bonded to the inner layer circuit board side or the inner layer circuit board side on which components are mounted. In this way, the insulating resin layer with a carrier is laminated, and this is heated and pressed to maintain and smooth the insulating layer thickness by the first layer, and the inner layer circuit and mounted components by the second layer, etc. It is possible to achieve both good embedding and unevenness.
In addition, it is also possible to use the first layer and / or the second layer to join the carrier using two or more layers to form the insulating resin layer with a carrier of the present invention.

Although it does not specifically limit as a manufacturing method of the insulating resin layer of this invention, and the insulating resin layer with a carrier, The resin composition which forms the said 1st layer and the 2nd layer is made into the resin varnish which melt | dissolved in the solvent, respectively, It can be formed by coating this on a carrier using a coating apparatus, or sequentially coating in a predetermined order. By using the resin composition in the form of a resin varnish, the coating property is improved, and an insulating resin layer having high smoothness and high thickness accuracy can be obtained.
For example, the first layer of resin varnish is coated on a carrier, dried at a predetermined temperature (for example, 80 to 200 ° C.), and the first layer is formed by substantially removing the solvent to form a film. After the formation, the second layer is formed by coating the resin varnish of the second layer and forming the film in the same manner. By such a method, an insulating resin layer with a carrier can be obtained. The obtained insulating resin layer with a carrier can be used as it is, or the carrier can be peeled off and used as an insulating resin layer.

The solvent used when preparing the resin varnishes of the first layer and the second layer is desirably good solubility in the resin composition, but a poor solvent is used as long as it does not have an adverse effect. It doesn't matter.
Examples of good solvents for benzocyclobutene resins include toluene, xylene, mesitylene, cyclohexanone, and examples of good solvents for cyanate resins include MEK, MIBK, and cyclohexanone.

Next, the multilayer printed wiring board of the present invention will be described.
The multilayer printed wiring board of the present invention can be obtained by heating and press-molding the insulating resin layer of the present invention obtained above or the insulating resin layer with carrier on one or both sides of the inner circuit board. it can.
The method for producing the multilayer printed wiring board of the present invention is not particularly limited. For example, in addition to the method of heating and press-molding by superposing an insulating resin layer composed of two types of layers on the inner circuit board in advance. The first layer and the second layer can also be produced by a method in which the first layer and the second layer are temporarily pressure-bonded to the inner layer circuit board by a method such as laminating one layer or two or more layers, followed by heating and pressing.

When the multilayer printed wiring board of the present invention is manufactured, the second layer is provided on the inner circuit board side or the inner circuit board side on which the components are mounted, and the first layer or the first layer is provided on the opposite side. It is preferable to stack the insulating resin layers so that a plurality of layers including them are positioned and to heat and press mold them.
Accordingly, the thickness of the insulating layer can be maintained and smoothed by the first layer, and the embedding property of the unevenness of the inner layer circuit or the component can be imparted by the second layer.
When manufacturing a multilayer printed wiring board, the temperature to heat is although it does not specifically limit, 140-240 degreeC is preferable. Moreover, although the pressure to pressurize is not specifically limited, 1-4 MPa is preferable.

The multilayer printed wiring board of the present invention uses the insulating resin layer of the present invention to alleviate mechanical distortion that occurs when a thermal cycle load is applied, and to generate cracks that occur in resins near the metal such as chips and copper wiring. By suppressing the thermal reliability, it is possible to improve the thermal reliability without impairing the high frequency characteristics.
As a result, the components can be built in the substrate, and the components can be three-dimensionally arranged, thereby making it possible to reduce the size and increase the density of the substrate.

  Hereinafter, although an example and a comparative example explain the present invention, the present invention is not limited to this.

[Example 1]
1. Preparation of resin varnish (1) Preparation of first layer resin varnish Divinylsiloxane-bisbenzocyclobutene (B-staged, number average molecular weight 140) as the benzocyclobutene resin with respect to the entire solid content of the resin composition , 000, 55% by weight of “Cycloten XUR” manufactured by Dow Chemical Co., Ltd., 5% by weight of epoxidized SBR resin (number average molecular weight 100,000, “Epofriend CT-310” manufactured by Daicel Chemical Industries, Ltd.) as a thermoplastic elastomer, As a curing agent, 2% by weight of 1,2-bis (azidobenzyl) ethylene is dissolved in mesitylene, and further, silica (“Ad-25T” “SO-25H”, average particle size 0.6 μm, maximum particle size) as an inorganic filler. 5 μm) 38% by weight is added and dispersed to prepare a resin varnish for the first layer so that the nonvolatile content concentration is 50% by weight. It was.

(2) Preparation of resin varnish for second layer 33% by weight of novolak cyanate resin (weight average molecular weight 560, “PT-60” manufactured by Lonza Japan) as a cyanate resin, based on the entire solid content of the resin composition , 10% by weight of novolak type cyanate resin (weight average molecular weight 380, “PT-30” manufactured by Lonza Japan), bisphenol F type phenoxy resin (weight average molecular weight 6,000, “Epicoat 4010P” manufactured by Japan Epoxy Resin) 15 % By weight, 2% by weight of novolak type phenolic resin (“HF-3” manufactured by Sumitomo Bakelite Co., Ltd.) dissolved in methyl ethyl ketone, and silica (“SO-25H” manufactured by Admatechs Co., Ltd.) with an average particle size of 0. (6 μm, maximum particle size 5 μm) is added and dispersed by adding 40% by weight to a non-volatile content of 50% by weight. A second layer varnish was prepared as described above.

2. Production of Insulating Resin Layer with Carrier A copper foil (thickness: 18 μm, manufactured by Furukawa Circuit Foil Co., Ltd.) was coated with the first layer resin varnish at a thickness of 40 μm, and the temperature was maintained at 170 ° C. for 10 minutes in a 150 ° C. drying oven. Were dried for 10 minutes in a drying oven to form a first layer having a thickness of 20 μm.
Subsequently, the second layer resin varnish was applied in the same manner at a thickness of 120 μm, dried in a drying furnace at 110 ° C. for 10 minutes, and dried in a drying furnace at 150 ° C. for 10 minutes, and a 60 μm thick first varnish was applied. By forming two layers, an insulating resin layer with a carrier having a total thickness of 80 μm of the insulating resin layer was produced.

3. Fabrication of multilayer printed wiring board Double-sided copper-clad multilayer printed wiring board having a copper foil thickness of 18 μm, line width and line width: L / S = 50/50 (size: length 4 cm, width 4 cm, thickness 0.6 mm) As described above, one chip (size: 5 mm long, 5 mm wide, 0.06 mm thick) is arranged on one side, and the insulating resin layer side of the insulating resin layer with the carrier is laminated on both sides, and 170 chips are formed. A multilayer printed wiring board was produced by heat-pressure bonding at 200 ° C. for 2 hours at 200 ° C. and thermosetting.

4). Preparation of Insulating Resin Layer with Carrier for Evaluation The first layer resin varnish was applied to a copper foil (thickness: 18 μm, manufactured by Furukawa Circuit Foil Co., Ltd.) at a thickness of 40 μm, and then dried in a drying oven at 150 ° C. for 10 minutes, 170 An insulating resin layer with a carrier for evaluation (first layer) having an insulating resin layer having a thickness of 20 μm was produced by drying in a drying oven at 0 ° C. for 10 minutes.
Similarly, a varnish for the second layer is applied to a copper foil (thickness 18 μm, manufactured by Furukawa Circuit Foil Co., Ltd.) at a thickness of 120 μm and dried in a drying furnace at 110 ° C. for 10 minutes and in a drying furnace at 150 ° C. for 10 minutes. Thus, an insulating resin layer with an evaluation carrier (second layer) having an insulating resin layer having a thickness of 60 μm was produced.

[Example 2]
1. Preparation of Resin Varnish A first layer resin varnish and a second layer resin varnish were prepared in the same manner as in Example 1 except that the blending ratio of the resin varnish was as follows.
As resin varnish for the first layer, 45% by weight of divinylsiloxane-bisbenzocyclobutene resin (cycloten XUR), 15% by weight of epoxidized SBR resin (Epofriend A1005), 1,2-bis (azidobenzyl) Ethylene was 2% by weight and silica (SO-25H) was 38% by weight.
As the resin varnish for the second layer, 30% by weight of novolak type cyanate resin (PT-60), 23% by weight of novolak type cyanate resin (PT-30), and 15% by weight of bisphenol F type phenoxy resin (Epicoat 4010P) The novolac type phenolic resin (HF-3) was 2% by weight and the silica (SO-25H) was 30% by weight.

2. Production of Insulating Resin Layer with Carrier The total thickness of the insulating resin layer is 80 μm in the same manner as in Example 1 except that the first layer resin varnish and the second layer resin varnish obtained above are used. An insulating resin layer with a carrier was prepared.

3. Production of multilayer printed wiring board A multilayer printed wiring board was produced in the same manner as in Example 1 except that the insulating resin layer with carrier obtained above was used.

4). Preparation of insulating resin layer with carrier for evaluation Insulating resin with carrier for evaluation in the same manner as in Example 1 except that the first layer resin varnish and the second layer resin varnish obtained above were used. Layers (first layer, second layer) were produced.

[Example 3]
1. Preparation of resin varnish In the same manner as in Example 1, a first layer resin varnish and a second layer resin varnish were prepared.

2. Preparation of Insulating Resin Layer with Carrier A copper foil (thickness: 18 μm, manufactured by Furukawa Circuit Foil Co., Ltd.) was coated with the first layer varnish at a thickness of 20 μm, and was dried at 150 ° C. for 10 minutes at 170 ° C. The film was dried in a drying furnace for 10 minutes to form a first layer having a thickness of 10 μm.
Subsequently, using the second layer varnish, the varnish was similarly applied at a thickness of 180 μm, dried in a drying furnace at 110 ° C. for 10 minutes, and dried in a drying furnace at 150 ° C. for 10 minutes, and a second 90 μm thick second. By forming this layer, an insulating resin layer with a carrier having a total thickness of 100 μm of the insulating resin layer was produced.

3. Production of multilayer printed wiring board A multilayer printed wiring board was produced in the same manner as in Example 1 except that the insulating resin layer with carrier obtained above was used.

4). Preparation of Insulating Resin Layer with Carrier for Evaluation The first layer resin varnish was applied to a copper foil (thickness 18 μm, manufactured by Furukawa Circuit Foil Co., Ltd.) at a thickness of 20 μm, and then dried in a drying oven at 150 ° C. for 10 minutes, 170 An insulating resin layer (first layer) with a carrier for evaluation having a thickness of 10 μm was produced by drying for 10 minutes in a drying oven at 1 ° C.
Similarly, a varnish for the second layer is applied to a copper foil (thickness: 18 μm, manufactured by Furukawa Circuit Foil Co., Ltd.) at a thickness of 180 μm and dried in a drying furnace at 110 ° C. for 10 minutes and in a drying furnace at 150 ° C. for 10 minutes. Thus, an insulating resin layer with an evaluation carrier (second layer) having a thickness of 90 μm was produced.

[Example 4]
1. Preparation of Resin Varnish A first layer resin varnish and a second layer resin varnish were prepared in the same manner as in Example 1 except that the blending ratio of the resin varnish was as follows.
As a resin varnish for the first layer, 65% by weight of divinylsiloxane-bisbenzocyclobutene resin (cycloten XUR), 5% by weight of epoxidized SBR resin (Epofriend A1005), 1,2-bis (azidobenzyl) Ethylene was 2 wt% and silica (SO-25H) was 28 wt%.
As the resin varnish for the second layer, 23% by weight of novolak type cyanate resin (PT-60), 10% by weight of novolak type cyanate resin (PT-30), and 25% by weight of bisphenol F type phenoxy resin (Epicoat 4010P) The novolak type phenol resin (HF-3) was 2% by weight and the silica (SO-25H) was 40% by weight.

2. Production of Insulating Resin Layer with Carrier The total thickness of the insulating resin layer is 80 μm in the same manner as in Example 1 except that the first layer resin varnish and the second layer resin varnish obtained above are used. An insulating resin layer with a carrier was prepared.

3. Production of multilayer printed wiring board A multilayer printed wiring board was produced in the same manner as in Example 1 except that the insulating resin layer with carrier obtained above was used.

4). Preparation of insulating resin layer with carrier for evaluation Insulating resin with carrier for evaluation in the same manner as in Example 1 except that the first layer resin varnish and the second layer resin varnish obtained above were used. Layers (first layer, second layer) were produced.

[Example 5]
1. Preparation of Resin Varnish A first layer resin varnish and a second layer resin varnish were prepared in the same manner as in Example 4.

2. Production of Insulating Resin Layer with Carrier The total thickness of the insulating resin layer was 100 μm in the same manner as in Example 3 except that the first layer resin varnish and the second layer resin varnish obtained above were used. An insulating resin layer with a carrier was prepared.

3. Production of multilayer printed wiring board A multilayer printed wiring board was produced in the same manner as in Example 1 except that the insulating resin layer with carrier obtained above was used.

4). Production of insulating resin layer with carrier for evaluation Insulating resin with carrier for evaluation in the same manner as in Example 3 except that the resin varnish for the first layer and the resin varnish for the second layer obtained above were used. Layers (first layer, second layer) were produced.

[Comparative Example 1]
1. Preparation of Resin Varnish The first layer resin varnish prepared in Example 1 was used.

2. Preparation of Insulating Resin Layer with Carrier A copper foil (thickness: 18 μm, manufactured by Furukawa Circuit Foil Co., Ltd.) was coated with the above resin varnish at a thickness of 160 μm, 10 minutes in a drying furnace at 150 ° C., 10 minutes in a drying furnace at 170 ° C. An insulating resin layer with a carrier with a thickness of 80 μm was prepared by drying for a minute and forming a resin layer with a thickness of 80 μm.

3. Production of multilayer printed wiring board A multilayer printed wiring board was produced in the same manner as in Example 1 except that the insulating resin layer with carrier obtained above was used.

4). Production of insulating resin layer with carrier for evaluation The insulating resin layer with carrier obtained above was used.

[Comparative Example 2]
1. Preparation of Resin Varnish The second layer resin varnish prepared in Example 1 was used.

2. Preparation of Insulating Resin Layer with Carrier A copper foil (thickness: 18 μm, manufactured by Furukawa Circuit Foil Co., Ltd.) was coated with the resin varnish at a thickness of 160 μm, 10 minutes in a 110 ° C. drying oven, 10 minutes in a 150 ° C. drying oven. An insulating resin layer with a carrier with a thickness of 80 μm was prepared by drying for a minute and forming a resin layer with a thickness of 80 μm.

3. Production of multilayer printed wiring board A multilayer printed wiring board was produced in the same manner as in Example 1 except that the insulating resin layer with carrier obtained above was used.

4). Production of insulating resin layer with carrier for evaluation The insulating resin layer with carrier obtained above was used.

[Evaluation]
Characteristic evaluation was performed using the multilayer printed wiring board obtained by the Example and the comparative example, and the insulating resin layer with the carrier for evaluation. The results are shown in Table 1.

Evaluation was performed by the following method.
1. Evaluation of Insulating Resin Layer (1) Relative Dielectric Constant: Measured under conditions of A state using JIS C 6481 in accordance with JIS C 6481 using an insulating resin layer with an evaluation carrier (first layer) and an insulating resin layer with a carrier.
(2) Water absorption: E-24 / 50 + D-24 / 23 in accordance with JIS C 6481 using an insulating resin layer with an evaluation carrier (first layer, second layer) and an insulating resin layer with a carrier. It measured on condition of this.
(3) Linear expansion coefficient: It measured between R10 degreeC and 35 degreeC-85 degreeC using the insulating resin layer (2nd layer) with a carrier for evaluation, and the insulating resin layer with a carrier.
(4) Tensile strength: Using an insulating resin layer with a carrier for evaluation (second layer) and an insulating resin layer with a carrier, a load full scale of 20 kgf and a speed of 5 mm / min. It measured on condition of this.

2. Evaluation of multilayer printed wiring board (1) Cooling cycle test The multilayer printed wiring board was immersed in a liquid bath at -65 ° C for 30 minutes and then immersed in a liquid bath at 125 ° C for 30 minutes. The presence or absence of cracks was confirmed by observing the cross section of the surrounding resin layer.
○: No crack occurrence ×: Crack occurrence

Examples 1 to 5 are insulating resin layers of the present invention comprising a first layer having a relative dielectric constant of 3.2 or less and a second layer having a linear expansion coefficient at room temperature of 40 ppm / ° C. or less. It had high mechanical strength and excellent dielectric properties. In addition, the multilayer printed wiring board of the present invention using this insulating resin layer has high reliability during heat, and an insulating resin layer having excellent thickness accuracy can be formed.
On the other hand, Comparative Example 1 was an insulating resin layer formed only from the first layer, but the mechanical strength was reduced and cracks were generated in the cooling / heating cycle test. Comparative Example 2 was an insulating resin layer formed only from the second layer, but the water absorption rate was reduced. And the multilayer printed wiring board using these became inferior in the characteristic of connection reliability.

The insulating resin layer of the present invention has high mechanical strength and excellent dielectric properties, and improves the mechanical strength around the components without impairing the dielectric properties around the high frequency circuit compared to the conventional one. A multilayer printed wiring board can be manufactured. Therefore, the insulating resin layer of the present invention can be suitably used for a multilayer printed wiring board having built-in components, corresponding to miniaturization and high density of the package substrate.
The multilayer printed wiring board of the present invention can be used particularly suitably for applications that require miniaturization, high density, and high performance, such as printed wiring boards for small information processing equipment.

Claims (5)

An insulating resin layer used for a multilayer printed wiring board, wherein the insulating resin layer includes a benzocyclobutene resin and / or a prepolymer thereof and an inorganic filler, and has a relative dielectric constant of 3.2 or less . And a second layer having a coefficient of linear expansion of 40 ppm / ° C. or less , comprising a cyanate resin and / or a prepolymer thereof and an inorganic filler, and the resin composition forming the first layer is: The resin composition containing 30 to 90% by weight of the benzocyclobutene resin and / or its prepolymer with respect to the total solid content in the resin composition forming the first layer, and forming the second layer is a cyanate resin and / or a prepolymer containing 10 to 50% by weight relative to the total solid content of the resin composition forming the second layer, and laminated on at least one layer each, the number of the benzocyclobutene resin Rights Insulating resin layer, wherein the molecular weight is 3000～1,000,000.
The insulating resin layer according to claim 1, wherein the first layer has a water absorption rate of 0.8% by weight or less. An insulating resin layer with a carrier comprising the insulating resin layer according to claim 1 and a carrier bonded to at least one surface thereof. A multilayer printed wiring board obtained by laminating the insulating resin layer according to claim 1 or 2 on at least one surface of an inner layer circuit board, and heating and pressing. A multilayer printed wiring board, wherein the insulating resin layer with a carrier according to claim 3 is laminated on at least one side of an inner layer circuit board, and heated and pressurized.