JP2010087013A - Method for manufacturing inter-layer insulating sheet, built-up multilayer substrate, and circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inter-layer insulating sheet for a built-up multilayer substrate that provides fine processability in a B stage, a built-up multilayer substrate using the inter-layer insulating sheet, and a method for manufacturing the insulating sheet and the multilayer substrate. <P>SOLUTION: According to the inter-layer insulating sheet for the built-up multilayer substrate, the built-up multilayer substrate using the inter-layer insulating sheet, and the method for manufacturing the insulating sheet and the multilayer substrate, a thermocuring resin composition includes essential elements of (A) an epoxy resin, (B) an epoxy resin curing agent, (C) a curing accelerator, (D) a polymeric epoxy resin and/or a phenoxy resin having a molecular weight of 10,000 or more, and (E) an inorganic filler. The epoxy resin (A) and/or the epoxy resin curing agent (B) contain a biphenyl skeleton and/or a naphthalene skeleton and also contains a liquid epoxy resin and/or a liquid curing agent for an epoxy resin of 1.5 to 25 wt.%. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a buildup type multilayer substrate interlayer insulation sheet, a buildup type multilayer substrate, and a method for producing a circuit board, and the interlayer insulation sheet is particularly preferably used for a buildup type multilayer printed wiring board.

As electronic devices become lighter, thinner, and more compact, the substrate density is increasing. Along with this, the use of build-up substrates capable of higher density is also increasing. In order to further reduce the thickness of build-up substrates that repeatedly laminate insulating layers and conductive layers and increase the efficiency of laser processing, the study of substrates that use films as the substrate instead of conventional fiber substrates has also been promoted. (For example, Patent Document 1).
However, the epoxy resin often used for printed wiring boards is poor in flexibility, and therefore, when applied to an insulating film that is thin and bends easily, a phenomenon that the resin breaks and peels off from the base material easily occurs. This phenomenon is particularly remarkable in the B stage in a semi-cured state, and often becomes a big problem in manufacturing operations.
As a means for solving this, a method of blending a flexible component such as rubber (elastomer) is generally performed, but when a rubber component is blended, the heat resistance, flame retardancy, and dimensional stability of the resin composition There is also a problem in that various characteristics such as property and electrical characteristics are degraded (for example, Patent Document 2). In particular, regarding flame retardancy, there is a movement to limit the use of halogen-based flame retardants due to environmental problems in recent years, so the difficulty of ensuring flame retardancy of resin compositions has increased, and as a result, rubber components It is also expected that the addition blending makes it difficult to maintain the property balance of the entire resin composition.
On the other hand, as an interlayer adhesive sheet (insulating sheet) using an epoxy resin, one using an alkoxy group-containing silane-modified epoxy resin by modifying glycidol, which is an epoxy compound having a hydroxyl group, has been proposed (for example, Patent Documents). 3, 4). However, since an epoxy compound having a hydroxyl group is used, the stability is not sufficient.
Patent Documents 5 and 6 disclose interlayer insulating materials using a thermosetting resin composition made of an epoxy resin containing 50 to 100% by weight or 20 to 70% by weight of a liquid epoxy resin. However, it is not a technique for improving flame retardancy without using a flame retardant.

JP 2008-78292 A JP 2004-59777 A JP 2002-212262 A JP 2003-48955 A JP 2007-224242 A JP 2008-37957 A

  The subject of this invention is providing the interlayer insulation sheet for buildup type | mold multilayer substrates with which the flame retardance and the physical property balance of the whole resin composition were taken.

As a result of repeating sincerity studies to achieve the above object, the present inventors have blended a specific amount of a liquid epoxy resin or a liquid curing agent, so that flame retardancy, mechanical properties, heat resistance, etc. It was found that an interlayer insulation sheet for a build-up type multilayer substrate and a build-up type multilayer substrate using the same can be obtained, and the present invention has been completed.
That is, the present invention is an interlayer insulating sheet provided with an adhesive layer made of a thermosetting resin composition containing an inorganic filler on one or both sides of the following (1) insulating film, wherein the thermosetting resin composition is ,
(A) epoxy resin,
(B) a curing agent for epoxy resin,
(C) a curing accelerator,
(D) a high molecular weight epoxy resin having a molecular weight of 10,000 or more and / or a phenoxy resin,
(E) An inorganic filler is an essential component, and (A) an epoxy resin or / and (B) a curing agent for an epoxy resin contains a biphenyl skeleton or / and a naphthalene skeleton, and a liquid epoxy resin or / and an epoxy An interlayer insulation sheet for a build-up type multilayer board, comprising 1.5 to 25% by mass of a liquid curing agent for resin;
(2) The interlayer insulation sheet for buildup type multilayer substrates according to the above (1), wherein the thermosetting resin composition contains spherical silica as an inorganic filler (E),
(3) The interlayer insulating sheet for a buildup type multilayer substrate according to the above (1) or (2), wherein the insulating film is a polyimide film having a thickness of 25 μm or less,
(4) The interlayer insulation sheet for a buildup type multilayer substrate according to any one of (1) to (3), wherein a dimensional shrinkage ratio after curing of the interlayer adhesive sheet is 0.1% or less,
(5) A through hole provided in the interlayer insulation sheet for buildup type multilayer substrate according to any one of (1) to (4), a conductive paste filled in the through hole, and electrically Build-up type multilayer board characterized by having wiring to connect,
(6) A hole is formed in the adhesive sheet for a build-up type multilayer substrate according to any one of the above (1) to (4) provided with an adhesive layer on both sides, and this hole is filled with a conductive paste. A method of manufacturing a circuit board, characterized in that the surface is laminated on the circuit side of the inner layer board on which the circuit is formed on one side or both sides, and multilayered,
(7) A hole is formed in the interlayer insulation sheet for build-up type multilayer substrate according to any one of the above (1) to (4), which is provided with an adhesive layer on both sides, and this hole is filled with a conductive paste. A method of manufacturing a circuit board, wherein one surface is bonded to the circuit side of the inner layer substrate on which the circuit is formed on one side, and the other surface is superimposed on the copper foil, and then the circuit is formed on the copper foil to form a multilayer. ,
(8) The insulating sheet for a build-up type multilayer substrate according to any one of (1) to (4) above is overlaid on an inner layer substrate on which a circuit is formed with conductive protrusions provided by conductive paste or metal. A method of manufacturing a circuit board, comprising: pasting a protrusion, attaching a copper foil to a side of the build-up type multilayer board insulating sheet through which the protrusion has penetrated and projecting, and keeping both layers conductive. ,
(9) The build-up type multilayer substrate insulating sheet according to any one of (1) to (4) above is overlaid on a copper foil provided with conductive protrusions by a conductive paste or metal. A method of manufacturing a circuit board, characterized in that after being penetrated, the build-up type multilayer board insulating sheet is laminated with copper foil on the side through which the protrusion penetrates and protruding, and multilayered while keeping both layers conductive. It is to provide.

  According to the present invention, resin peeling from the base film is suppressed without adding a rubber component, and B stage (in the present invention, B stage refers to a state in which the thermosetting resin composition is semi-cured). An interlayer insulation sheet for a buildup type multilayer substrate having a good balance between the handleability and physical properties of the substrate can be obtained, and by using the interlayer insulation sheet, a buildup type multilayer substrate can be obtained.

Hereinafter, the present invention will be described in detail.
A thermosetting resin composition used for an interlayer insulating sheet for a buildup type multilayer substrate of the present invention (hereinafter sometimes simply referred to as an interlayer insulating sheet) contains an inorganic filler as an essential component, and is a liquid epoxy resin Or / and a liquid curing agent is contained as an essential component. In the present invention, the liquid state means a state in which fluidity can be confirmed with the naked eye at 25 ° C., and the liquid state includes a semi-solid state.
The semi-solid state refers to a waxy state or a state in which liquid and crystals are mixed at 25 ° C.

The epoxy resin of component (A) used in the present invention includes an epoxy resin having a molecular weight of less than 10,000 and having two or more epoxy groups in one molecule.
The molecular weights referred to in the present invention are all weight average molecular weights measured by GPC.
Specific examples include bisphenol A type epoxy resins, bisphenol F type epoxy resins, biphenyl type epoxy resins, novolac type epoxy resins, and alicyclic epoxy resins, which can be used alone or in combination of two or more. .
In particular, an epoxy resin containing a biphenyl skeleton, a naphthalene skeleton, or the like is used as an essential component for improving the flame retardancy and dimensional stability of the resin composition.
In addition, there is no resin cracking or peeling from the film, and from the viewpoint of improving the handleability at the B stage, etc., in the thermosetting resin composition in the present invention, at least a part of the epoxy resin of the component (A) At least a part of the liquid epoxy resin and / or the epoxy curing agent (B), which will be described in detail later, must contain the liquid curing agent as an essential component.
Among the epoxy resins of component (A), as the liquid epoxy resin, naphthalene type liquid epoxy resin (for example, Dainippon Ink, HP4032, epoxy equivalent 152), bisphenol A type liquid epoxy resin [for example, Japan Epoxy Resin Co., Ltd. Manufactured by iER828, epoxy equivalent 190, manufactured by Tohto Kasei Co., Ltd., trade name “Epototo YD-128”, epoxy equivalent 190], bisphenol F type epoxy liquid resin [eg, Dainippon Ink, trade name “Epicron 830”, epoxy Equivalent 180] and the like.
Furthermore, an epoxy compound having one epoxy group in one molecule (reactive diluent such as phenyl glycidyl ether) may be added within a range not impairing the object of the present invention.

The epoxy resin curing agent (B) used in the present invention can be used without particular limitation as long as it is a compound usually used in epoxy resin curing agents. For example, examples of the amine curing agent include dicyandiamide and aromatic diamine. Examples of the phenol curing agent include phenol novolac resin, cresol novolac resin, bisphenol A novolak resin, triazine modified novolak resin, imide modified novolac resin, , Biphenyl skeleton-containing novolak resins, naphthol-based polyfunctional curing agents, and the like, which can be used alone or in combination of two or more.
In particular, a novolac-based curing agent containing a biphenyl skeleton, a naphthalene skeleton, or the like can be preferably used for improving the flame retardancy and dimensional stability of the resin composition. In order to improve the handleability at the B stage, a liquid novolac resin such as an imide-modified liquid novolak resin, or a liquid curing agent such as a liquid aromatic diamine must be used as an essential component together with the liquid epoxy resin or alone. Don't be.

  As the curing accelerator of the component (C) used in the present invention, any compound that is usually used as a curing accelerator for epoxy resins can be used without particular limitation. For example, imidazoles such as 2-methylimidazole, 2-phenylimidazole, 2-ethyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 2-heptadecylimidazole; boron trifluoride monoethylamine complex, etc. Boron trifluoride amine complex; organic phosphines such as triphenylphosphine, methyldiphenylphosphine, triphenylphosphine, diphenylphosphine, phenylphosphine; triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, tris (dimethylaminomethyl) ) Tertiary amines such as phenol; tetraphenylphosphonium / tetraphenylborate, tetraphenylborate, N-methylmorpholine / tetraphenylborate Such as tetraphenyl boron salts and the like. These can be used alone or in admixture of two or more.

The component (D) used in the present invention is a high molecular weight epoxy resin and / or a phenoxy resin, but as a high molecular weight epoxy resin having a molecular weight of 10,000 or more, both are made by Japan Epoxy Resin Co., Ltd. and jER1256 (bisphenol A type epoxy resin). , Molecular weight of about 500,000), jER YX8100BH30 (bisphenol A type epoxy resin, molecular weight 38,000, resin solid content 30% by weight), jER YX6954 (bisphenol A type epoxy resin, molecular weight 39,000), etc. Can be used alone or in combination of two or more.
Examples of the phenoxy resin having a molecular weight of 10,000 or more include FX280AXM40 (phenoxy resin manufactured by Toto Kasei Co., Ltd., Mw = about 45,000, resin solid content 40% by weight), YP-50S [bisphenol A type phenoxy resin manufactured by Toto Kasei Co., Ltd., Mw = 50000] etc., and these can be used alone or in combination of two or more. In particular, a material having a high Tg such as jER YX8100 can be preferably used for improving the heat resistance of the resin composition.
When both high molecular weight epoxy resin and phenoxy resin are used as the component (D), the ratio of the former / the latter may be arbitrary.

As the inorganic filler of the component (E) used in the present invention, any compound that is generally used as a filler for an insulating material can be used without particular limitation. Specific examples include silica (spherical silica, crushed silica), alumina, aluminum hydroxide, magnesium hydroxide, and the like. These can be used alone or in combination of two or more. In particular, spherical silica can be preferably used because dimensional stability can be improved by high filling. In order to cope with the recent increase in the density of printed circuit boards, the dimensional stability of the material is an important characteristic.
In particular, in a build-up type multilayer printed wiring board that performs laser drilling for interlayer connection in a semi-cured state, it is considered that the connection reliability of the substrate can be improved by reducing the dimensional shrinkage ratio before and after curing. Specifically, by suppressing the dimensional shrinkage ratio after curing to 0.1% or less, the connection reliability of the substrate can be improved.

The resin composition containing the components (A) to (E) contains the liquid epoxy resin and / or the curing agent described above in an amount of 1.5 to 25% by mass, preferably 2 to 18% by mass, based on the total amount of the resin composition. Thus, it is possible to obtain an interlayer insulating sheet having good handleability on the B stage.
By setting the liquid epoxy resin and / or curing agent to 1.5% by mass or more, an improvement effect is sufficiently exerted against resin cracking at the B stage of the interlayer insulating sheet and resin peeling from the insulating film. Moreover, when using a release film, it prevents that troubles, such as insufficient adhesion of a release film, become easy to generate | occur | produce.
By setting it to 25% by mass or less, the tackiness at the B stage becomes too strong, and the handling property is lowered, and the occurrence of the problem that the melt viscosity of the resin is extremely lowered is prevented, and Prevents deterioration of processability of edge fusion and laser through-holes. Further, when the conductive paste is filled into the through hole using a squeegee or the like, the filling portion is prevented from being dented and connection reliability is lowered.

The blending ratio of the above components (A) to (E) in the thermosetting resin composition to be the adhesive layer in the interlayer insulating sheet of the present invention is as follows [total amount of components (A) to (E) Is 100% by mass].
(A) component: 17-70 mass%, Preferably, 10-40 mass%
Component (B): 0.5 to 35% by mass, preferably 0.5 to 20% by mass
[However, in the component (B), the blending amount of the resin component that does not become a cured resin component such as dicyandiamide or aromatic diamine is 0.5 to 10% by mass, preferably 0.5 to 5% by mass. ]
Component (C): 0.01 to 5% by mass, preferably 0.01 to 1% by mass
Component (D): 5 to 40% by mass (as solid content 30% by mass), preferably 5 to 20% by mass
(E) component: 20 to 80% by mass, preferably 50 to 70% by mass
When the component (A) is in the above range, heat resistance and dimensional stability are ensured, and when the component (B) is in the above range, heat resistance and dimensional stability are ensured. Moreover, by making (C) component into the said range, heat resistance is ensured, By making (D) component into the said range, the handleability in B stage is ensured, and (E) component is made into the said range. By doing so, dimensional stability and handleability at the B stage are ensured.

In the resin composition containing (A) to (E) as components, if necessary, as a component (F), a flame retardant such as a phenoxyphosphazene oligomer, a coupling agent, an antifoaming agent, a leveling agent, Additives such as pigments, dyes, and plasticizers can be added. In particular, when flame retardancy is required, it is necessary to add a flame retardant, and in terms of environmental friendliness, it is necessary to use a flame retardant containing no halogen.
Insulating films used for the interlayer insulating sheet of the present invention are generally substrates such as Kapton (made by Toray DuPont, trade name), Upilex (made by Ube Industries, trade name), and Apical (made by Kaneka, trade name). The polyimide film currently used as a material can be used. In particular, materials having low heat shrinkage such as Kapton EN, Upilex S, and Apical NPI can be preferably used for improving dimensional stability.

The interlayer insulation sheet for a build-up type multilayer substrate of the present invention has a solid content of 30 by diluting the components (A) to (E) and other components added as necessary with an organic solvent.
-80% by mass of varnish, applied to one or both sides of an insulating film such as the above-mentioned polyimide film, dried to make the thermosetting resin composition semi-cured to the B stage state. be able to.
For the application of the varnish, conventionally known methods such as spin coating method, spray coating method, bar coating method, knife coating method, roll coating method, blade coating method, die coating method, and gravure coating method can be applied.
Organic solvents that can be used include ketones such as methyl ethyl ketone and methyl isobutyl ketone, esters such as methyl cellosolve, ethyl acetate, butyl acetate and propylene glycol monoacetate, alcohols such as propanol and butanol, toluene and xylene. And aromatic amides such as dimethylformamide. These can be used alone, or can be used as a mixture of two or more.

In addition, after apply | coating the said varnish on the single side | surface or both surfaces of an insulating film, after drying and removing a solvent to make a semi-hardened insulating sheet, a release paper and a release film are applied to a thermosetting resin composition application surface with a heating roll. A mold release material may be provided, and at this time, an interlayer insulation sheet for a buildup type multilayer substrate with a mold release material can be obtained by pressure bonding at a linear pressure of about 2 to 200 N / cm and a temperature of about 60 to 150 ° C. .
In order to further cure the obtained interlayer insulation sheet for a build-up type multilayer substrate with a release material, it is processed at a temperature of about 30 to 200 ° C. and a heating time of about 1 minute to 150 hours, and is heated and aged to build up. The amount of resin flow (resin flow) at the time of hot pressing during molding can be appropriately adjusted. Appropriate melt viscosity (measured with a flow tester CFT-100D manufactured by Shimadzu Corporation) at a temperature of 2 ° C./minute, a die length of 10 mm, and a die hole diameter of 1.0 mm under a measurement condition of 300 to 3000 Pa. By adjusting to s etc., good connection reliability can be obtained even in a build-up board of a type that performs interlayer connection with a conductive paste.

  At this time, the total thickness of the insulating film and the adhesive layer is preferably 5 μm to 55 μm, and more preferably 10 μm to 45 μm. If it is thinner than 5 μm, the adhesive strength is remarkably lowered and the embedding property of the circuit may be hindered. If it is thicker than 55 μm, the cost is increased, and the current situation where space saving and fine patterning are required is not suitable. .

  In drying after applying the thermosetting resin composition to the insulating film, a temperature of 80 to 180 ° C. is preferable. The reason for this is that if this heat drying is insufficient, the organic solvent component of the resin composition remains and voids are generated after build-up molding, and the reliability such as adhesion and solder heat resistance is reduced. If it is excessively heat-dried, the B-stage state of the surface of the resin composition will proceed, resulting in a decrease in pot life, unevenness in the adhesion with the metal foil or insulating film after build-up molding, and the result This is because unevenness of strength and weakness occurs in the peel strength, solder heat resistance, and dielectric characteristics of the metal foil.

Next, the build-up type interlayer insulating sheet for a multilayer substrate is built up as a build-up material to a core material. In the case of a build-up material for a double-sided adhesive layer, a conductive layer can be formed by laminating metal foil or the like. By laminating metal foils to form a pressure-receiving body, and heating and pressing the pressure-receiving body, the thermosetting resin composition of the build-up material can be cured to obtain a multilayer laminate.
The thickness of the metal foil used in the present invention is preferably 3 to 35 μm, and more preferably 5 to 18 μm. If the thickness of the metal foil is less than 3 μm, the mechanical properties of the metal foil are deteriorated, so that the working efficiency is remarkably reduced. If the thickness is more than 18 μm, it becomes difficult to sharpen the metal edge during etching, and a fineness of 100 μm or less is difficult. In pattern circuit fabrication, it becomes extremely difficult to adjust to a target circuit pitch.

As the metal foil, copper foil, aluminum foil or the like can be used. However, in consideration of subsequent processes such as circuit formation, copper foil is preferable, and the types of copper foil used here are rolled copper foil, electrolytic A copper foil etc. are mentioned, These can be used suitably according to a use.
As a method for forming the conductive layer, the conductive layer can also be obtained by a known thin film forming method such as sputtering, vacuum deposition, electroless plating, and electrolytic plating.
In addition, the above pressurization is performed for joining the metal foil and the buildup material and adjusting the thickness, and the pressurization conditions can be selected as necessary, but the crosslinking in the thermosetting resin composition. Since the reaction depends mainly on the reaction characteristics of the curing agent, the heating temperature and the heating time are selected according to the type of the curing agent. For example, in the above-mentioned thermosetting resin composition, generally, the temperature is 150 to 300 ° C., the pressure is 2.5 to 5.9 MPa (25 to 60 kg / cm ² ), and the time is about 10 to 180 minutes.
The ultra-thin multilayer substrate of the present invention uses a double-sided metal foil-clad laminate as the core material (inner layer substrate). First, a circuit forming process such as a subtractive method is applied to the double-sided metal foil-clad laminate. By applying, a circuit pattern on both sides is formed. In addition, what laminated | stacked metal foil on both surfaces of the interlayer insulation sheet for buildup type multilayer substrates of this invention can also be used as a core material (inner layer board | substrate) at this time.

  Next, in order to make a multilayer, the interlayer insulation sheet for the buildup type multilayer substrate of the present invention is bonded to both surfaces of the inner layer substrate on which the circuit pattern is formed, and the interlayer insulation sheet for the buildup type multilayer substrate is punched. A build-up layer is formed by forming a circuit on the surface of the interlayer insulating sheet for the up-type multilayer substrate. More specifically, after stacking a metal foil such as a copper foil on the surface of the inner layer substrate on which the circuit pattern is formed via the interlayer insulating sheet for a build-up type multilayer substrate, the layers are integrated and laminated by heating and pressing. After forming the build-up layer in this way, the circuit pattern is formed on the metal foil of the build-up layer by performing the same circuit forming process as described above, and for connecting a plurality of circuit patterns. A via hole (plating through hole) for signal transmission may be formed to connect the layers. The build-up layer may be formed only on one side of the laminated board on which a circuit pattern is formed as necessary.

In addition, as a method for producing a circuit board by multilayering, the following method can be used, and an interlayer insulating sheet for a build-up type multilayer board according to the present invention having a dimensional shrinkage of 0.1% or less is used. In this case, it is particularly preferable to use multilayering by the following two methods because it is suitable for achieving fine patterning.
One of the methods is a method in which a resin sheet having a hole is filled with a conductive paste and then multilayered. Specifically, a known method (for example, a laser drilling method such as a carbon dioxide laser or a UV-YAG laser, drilling by a drill, etc.) is formed on an interlayer insulating sheet for a build-up type multilayer substrate having adhesive layers on both sides. Holes), and through holes are formed as via holes. After filling the holes with conductive paste, this is laminated to the circuit side of the circuit board on which the circuit is formed on one or both sides. Drill a hole in the interlayer insulation sheet for build-up type multilayer boards provided with an adhesive layer, fill the hole with a conductive paste, and paste this together with a circuit board with a circuit formed on one side, and copper foil on the other side After the layers are stacked, a circuit is formed on the copper foil and multilayered, whereby a build-up type circuit board can be manufactured (hole filling method).
At this time, the above operation may be performed while the release film is stuck on both surfaces of the build-up type multilayer substrate interlayer insulating sheet, and as a method of filling the hole with the conductive paste, known printing, What is necessary is just to perform by methods, such as die coating.

  Also, as another method, the interlayer insulating sheet for the build-up type multilayer substrate of the present invention is overlaid on the inner layer substrate formed with a circuit provided with conductive protrusions by conductive paste or metal, and the protrusions are penetrated, A copper foil is laminated on the side where the protrusion penetrates through the interlayer insulation sheet for build-up type multilayer substrate, and it is made multilayer while taking conduction between both layers, or conductive protrusion is provided by conductive paste or metal The metal foil and the interlayer insulation sheet for build-up type multilayer substrates with through holes are aligned and overlapped to penetrate the protrusions, and then the protrusions penetrate the interlayer insulation sheet for build-up type multilayer substrates. A circuit board can be manufactured by laminating copper foil on the protruding side and forming multiple layers while maintaining conduction between both layers (bump method).

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not limited to these Examples. In the following examples and comparative examples, “part” represents “part by mass”.

[Preparation Example 1]
NC-3000 (trade name, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent 285) as a polyfunctional epoxy resin containing a biphenyl skeleton, and jER828 (trade name, manufactured by Japan Epoxy Resin Co., Ltd., epoxy equivalent 190) as a bisphenol A type liquid epoxy resin. 4 parts, 1.1 parts of dicyandiamide as a curing agent for epoxy resin, 0.04 part of 2-ethyl-4-methylimidazole as a curing accelerator, YX8100BH30 as a high molecular weight epoxy resin (trade name, molecular weight 38000, manufactured by Japan Epoxy Resin Co., Ltd.) Resin solid content 30%) 39 parts, spherical silica FB-3SDC (trade name, manufactured by Denki Kagaku Kogyo Co., Ltd., average particle size 3 um) 60 parts as inorganic filler, and epoxy silane coupling agent TSL8350 (manufactured by GE Toshiba Silicone) as other components Product name) 0.6 copies, one more Other ingredients as phenoxyphosphazene oligomer (melting point 100 ° C.) 7.5 parts, and the addition of 40 parts of methyl ethyl ketone and methyl cellosolve 40 parts to prepare a resin solid content of 50% by weight of the epoxy resin varnish as the organic solvent. In addition, the phenoxyphosphazene oligomer is mix | blended in order to improve a flame retardance.

[Preparation Examples 2 to 8]
Except having changed into the compounding ratio shown in Table 1, it carried out similarly to the preparation example 1, and prepared the epoxy resin varnish of 50 mass% of resin solid content.

[Comparative Preparation Examples 1 to 3]
Except having changed into the compounding ratio shown in Table 1, it carried out similarly to the preparation example 1, and prepared the epoxy resin varnish of 50 mass% of resin solid content.

[Examples 1-8 and Comparative Examples 1-3]
The epoxy resin varnishes prepared in Preparation Examples 1 to 8 and Comparative Preparation Examples 1 to 3 were dried on both sides of polyimide film Kapton 100EN (trade name, thickness 25 um, manufactured by Toray DuPont), and the thickness after drying was 10 um. It was applied and dried with a roll coater so that a semi-cured interlayer insulating sheet was obtained. This interlayer insulating sheet was evaluated for resin cracking and tackiness.
The carboxy-containing acrylonitrile butadiene rubber (trade name: Nipol 1072) used in Comparative Example 3 is manufactured by Nippon Zeon.
Next, a release film was laminated on the front and back of the interlayer insulating sheet under the conditions of 90 ° C. and 0.5 MPa to prepare an interlayer insulating sheet for a buildup type multilayer substrate. The adhesion after lamination of the interlayer insulating sheet, edge fusion, and processability of the laser through hole were evaluated.
This interlayer insulating sheet was press-cured under the conditions of 180 ° C., 4 MPa, and 60 minutes, and the characteristics of the glass transition temperature, flame resistance, and dimensional shrinkage of the cured product were evaluated.
The above evaluation results are shown in Table 1.

Measurement items were evaluated as follows.
(1) Resin cracking The semi-cured interlayer insulation sheet before press curing was bent to a self-diameter and evaluated according to the following criteria.
○: No cracking or peeling from the film △: No peeling from the film but abnormal appearance ×: Cracking or peeling from the film occurred (2) Tackiness of the semi-cured interlayer insulation sheet before press curing The state at room temperature was evaluated according to the following criteria.
○: No tack ×: With tack (3) Adhesiveness after lamination After leaving at 23 ° C. and 50% RH for 1 hour, the release film was peeled off by hand and evaluated according to the following criteria.
○: The resin layer does not cohesively break during peeling.
X: The resin layer cohesively breaks at the time of peeling.
(4) Edge fusion 10 layers of interlayer insulation sheet are cut into 5cm square, 1kg weight is placed, 1kg weight is placed and stored for 1 week in an atmosphere of 30 ° C and 80%, and end fusion is evaluated according to the following criteria. did.
○: Fusion is not confirmed.
X: Fusion can be confirmed.
(5) Workability of laser through hole Irradiation with a carbon dioxide laser is performed on the interlayer insulating sheet to provide a 0.2 mm diameter through hole, and the surface shape of the incident side and the through side is observed with a microscope. evaluated.
○: Resin bulge around the through hole cannot be confirmed.
Δ: Resin swell can be confirmed.
X: The release film is lifted or peeled off.
(6) Glass transition point Glass transition temperature was measured by DMA method using DMS6000 (product name) manufactured by Seiko Instruments Inc. The measurement conditions were a chuck distance of 20 mm, a frequency of 1 Hz, a measurement temperature range of 20 to 300 ° C., and a temperature increase rate of 5.0 ° C./min.
(7) Flame retardancy A flammability test was conducted by the UL-94 combustion test method.
(8) Dimensional Shrinkage A semi-cured interlayer insulating sheet was marked, and the position of this mark was measured before and after press curing.

  The interlayer insulating sheet of the present invention based on a film is free from resin cracking at the B stage, has good handleability, and does not contain a rubber component. Therefore, Tg, flame retardancy, dimensional stability, etc. Since the balance of various properties is excellent, it can be used for build-up type multilayer printed wiring boards.

Claims (9)

An interlayer insulating sheet provided with an adhesive layer made of a thermosetting resin composition containing an inorganic filler on one or both sides of an insulating film, wherein the thermosetting resin composition is
(A) epoxy resin,
(B) a curing agent for epoxy resin,
(C) a curing accelerator,
(D) a high molecular weight epoxy resin having a molecular weight of 10,000 or more and / or a phenoxy resin,
(E) An inorganic filler is an essential component, and (A) an epoxy resin or / and (B) a curing agent for an epoxy resin contains a biphenyl skeleton or / and a naphthalene skeleton, and a liquid epoxy resin or / and an epoxy An interlayer insulating sheet for a buildup type multilayer board, comprising 1.5 to 25% by mass of a liquid curing agent for resin.   The interlayer insulation sheet for buildup type multilayer substrates according to claim 1, wherein the thermosetting resin composition contains (E) spherical silica as an inorganic filler.   The interlayer insulation sheet for buildup type multilayer substrates according to claim 1 or 2, wherein the insulation film is a polyimide film having a thickness of 25 µm or less.   The interlayer insulation sheet for buildup type multilayer substrates according to any one of claims 1 to 3, wherein a dimensional shrinkage ratio after curing of the interlayer adhesive sheet is 0.1% or less.   5. A through-hole provided in the interlayer insulation sheet for build-up type multilayer substrate according to claim 1, a conductive paste filled in the through-hole, and a wiring that is electrically connected. Build-up type multilayer board characterized by that.   A build-up type multilayer substrate adhesive sheet according to any one of claims 1 to 4, wherein an adhesive layer is provided on both sides, and the hole is filled with a conductive paste. A method of manufacturing a circuit board, comprising: laminating multiple layers on the circuit side of an inner layer board on which circuits are formed on both sides.   5. The build-up type multilayer substrate interlayer insulating sheet according to claim 1, wherein an adhesive layer is provided on both sides, and a hole is filled with a conductive paste. A method of manufacturing a circuit board, comprising: laminating the inner layer board on which the circuit is formed on the circuit side, and superposing the other surface on the copper foil, forming a circuit on the copper foil, and forming a multilayer.   A build-up type multilayer substrate insulating sheet according to any one of claims 1 to 4 is superimposed on an inner layer substrate formed with a circuit provided with conductive protrusions by a conductive paste or metal, and the protrusions are penetrated. A method of manufacturing a circuit board, comprising: laminating a copper foil on a side of a protrusion through which a protrusion penetrates the insulating sheet for a build-up type multilayer board, and taking both layers into conduction.   The copper foil provided with conductive protrusions by conductive paste or metal is overlapped with the build-up type multilayer substrate insulating sheet according to any one of claims 1 to 4, and then the protrusions are penetrated. A method of manufacturing a circuit board, comprising: laminating copper foil on a side of a buildup type multilayer board insulating sheet through which a protrusion penetrates and projecting, and making the both layers conductive.