JP2008038066A - Prepreg, substrate and semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a prepreg compatible with thin-film formation and imparting both sides of its own with different applications, functions, performances or properties or the like, and to provide a substrate and a semiconductor device each having the prepreg. <P>SOLUTION: The prepreg comprises a sheet-like base material core layer, a first resin layer on one side of the core layer and a second resin layer on the other side of the core layer, to be used by forming a conductive layer on the first resin layer, wherein a first resin composition constituting the first resin layer and a second resin composition constituting the second resin layer differ from each other. The substrate is such as to be obtained by laminating the above-mentioned prepregs together. The semiconductor device is such as to have the above-mentioned substrate. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a prepreg, a substrate, and a semiconductor device.

  The circuit board is generally formed by laminating a plurality of prepregs obtained by impregnating a glass fiber base material with a thermosetting resin, and heating and pressurizing. And a prepreg is obtained by the method etc. which immerse a glass fiber base material etc. of thickness about 50-200 micrometers in the varnish of a thermosetting resin composition (for example, refer patent document 1).

  In some cases, the prepreg is required to have an embedding property for embedding a gap between circuit wirings on one surface and a plating adhesion property for forming a circuit on the other surface. However, the prepreg obtained by the conventional method of impregnating a glass fiber base material with a varnish of a thermosetting resin composition is formed of the same thermosetting resin composition on both sides. Therefore, a thermoplastic resin composition that satisfies both characteristics has been used.

  However, with recent downsizing and thinning of electronic parts and electronic devices, circuit boards and the like used therefor are required to be further downsized and thinned. In order to meet such demands, thinning of the prepreg constituting the circuit board has been studied. However, when the prepreg is thinned, it is difficult to satisfy both the embedding property and the plating adhesion. It was.

JP 2004-216784 A

An object of the present invention is to provide a prepreg that can cope with thinning and that can be provided with different uses, functions, performances, characteristics, and the like on both sides of the prepreg.
Moreover, the objective of this invention is providing the board | substrate and semiconductor device which have the said prepreg.

Such an object is achieved by the present invention described in the following (1) to (13).
(1) It has a core layer of a sheet-like base material, a first resin layer formed on one side of the core layer, and a second resin layer formed on the other side, on the first resin layer A prepreg used by forming a conductor layer, wherein the first resin composition constituting the first resin layer is different from the second resin composition constituting the second resin layer. Prepreg.
(2) The prepreg according to (1) above, wherein when a conductor layer is bonded to the first resin layer, a peel strength between the first resin layer and the conductor layer is 0.5 kg / cm or more.
(3) The prepreg as described in said (1) or (2) whose thickness of the 1st resin layer is 5-15 micrometers.
(4) The prepreg according to any one of (1) to (3), wherein the first resin composition includes a curable resin.
(5) The prepreg according to (4), wherein the curable resin includes a cyanate resin.
(6) The prepreg as described in (5) above, wherein the cyanate resin contains a novolac-type cyanate resin.
(7) The prepreg according to any one of (1) to (6), wherein the first resin composition further includes a curing agent.
(8) The prepreg according to (7), wherein the curing agent includes an imidazole compound.
(9) The prepreg according to any one of (1) to (8), wherein the first resin composition further includes a second resin of a different type from the curable resin.
(10) The prepreg according to (9), wherein the second resin includes a phenoxy resin.
(11) The prepreg according to any one of (1) to (10), wherein the thickness of the first resin layer is thinner than the thickness of the second resin layer.
(12) A substrate obtained by laminating the prepreg according to any one of (1) to (11) above.
(13) A semiconductor device comprising the substrate according to (12).

  According to the present invention, it is possible to obtain a prepreg which is excellent in moldability and plating adhesion, which are difficult to achieve with a thin material, and excellent in insulation reliability of a multilayer substrate and connection reliability as a semiconductor device. The prepreg of the present invention is suitably used for the production of multilayer substrates and semiconductor devices that are required to have higher density and thinner thickness.

Hereinafter, the prepreg, substrate and semiconductor device of the present invention will be described.
The prepreg of the present invention has a core layer of a sheet-like base material, a first resin layer formed on one side of the core layer, and a second resin layer formed on the other side, and the first resin A prepreg used by forming a conductor layer on a layer, wherein the first resin composition constituting the first resin layer is different from the second resin composition constituting the second resin layer. And
The substrate of the present invention is obtained by laminating the prepreg described above.
A semiconductor device according to the present invention includes the substrate described above.

First, a preferred embodiment of a prepreg will be described based on the drawings.
FIG. 1 is a cross-sectional view showing an example of the prepreg of the present invention.
The prepreg 10 has a core layer 11 of the sheet-like substrate 1, a first resin layer 2 formed on one side of the core layer 11, and a second resin layer 3 formed on the other side. The first resin composition constituting the first resin layer 2 and the second resin composition constituting the second resin layer 3 are different. As a result, it becomes possible to design a resin formulation according to the characteristics required for each layer, and as a result, it is possible to reduce the thickness of the entire prepreg while maintaining the characteristics required for each layer. . The prepreg 10 shown in FIG. 1 is used by forming a conductor layer on the first resin layer 2 (upper side in FIG. 1). Therefore, the first resin layer 2 is designed to have excellent adhesion with the conductor layer. Further, since the second resin layer 3 is required to have characteristics and the like different from those of the first resin layer 2, the second resin layer 3 is designed so as to satisfy it. Hereinafter, each layer will be described.

(Core layer)
The core layer 11 is mainly composed of the sheet-like substrate 1. The core layer 11 has a function of improving the strength of the prepreg 10.
The core layer 11 may be composed of the sheet-like substrate 1 alone, or the sheet-like substrate 1 may be impregnated with a part of the first resin layer 2 and the second resin layer 3 described above. .
Examples of such a sheet-like substrate 1 include glass fiber substrates such as glass woven fabrics and glass nonwoven fabrics, polyamide resin fibers, aromatic polyamide resin fibers, polyamide resin fibers such as wholly aromatic polyamide resin fibers, and polyester resin fibers. Synthetic fiber base materials composed of woven or non-woven fabrics mainly composed of polyester resin fibers such as aromatic polyester resin fibers and wholly aromatic polyester resin fibers, polyimide resin fibers and fluororesin fibers, kraft paper, cotton Examples thereof include fiber base materials such as organic fiber base materials such as linter paper, paper base materials mainly composed of linter and kraft pulp mixed paper, and resin films such as polyester and polyimide. Among these, a glass fiber base material is preferable. Thereby, the intensity | strength of the prepreg 10 can be improved. Moreover, the thermal expansion coefficient of the prepreg 10 can be reduced.

  As glass which comprises such a glass fiber base material, E glass, C glass, A glass, S glass, D glass, NE glass, T glass, H glass etc. are mentioned, for example. Among these, S glass or T glass is preferable. Thereby, the thermal expansion coefficient of a glass fiber base material can be made small, and, thereby, the thermal expansion coefficient of a prepreg can be made small.

  Although the thickness of a sheet-like base material (fiber base material) is not specifically limited, When obtaining a thin prepreg, 30 micrometers or less are preferable, especially 25 micrometers or less are preferable, and 10-20 micrometers is the most preferable. When the thickness of the sheet-like base material 1 is within the above range, the balance between the thinning of the substrate and the strength described later is excellent. Furthermore, it is excellent in processability and reliability of interlayer connection.

(First resin layer)
As shown in FIG. 1, the first resin layer 2 is formed on one side of the core layer 11 (upper side in FIG. 1).
The 1st resin layer 2 is comprised with the 1st resin composition, and is designed by the resin composition which is excellent in adhesiveness with a conductor layer.
The 1st resin composition excellent in adhesiveness with such a conductor layer contains (thermal) curable resin, a hardening adjuvant (for example, hardening agent, hardening accelerator, etc.), an inorganic filler, etc., for example.
In order to improve the adhesion with the conductor layer, a method using a curable resin excellent in the adhesion with the conductor layer, a curing aid for improving the adhesion with the conductor layer (for example, a curing agent, a curing accelerator, etc.) , A method using an acid-soluble material as an inorganic filler, a method using an inorganic filler and an organic filler in combination, and the like.
Examples of the curable resin having excellent adhesion to the conductor layer include urea (urea) resin, melamine resin, bismaleimide resin, polyurethane resin, resin having a benzoxazine ring, cyanate ester resin, bisphenol S type epoxy resin, bisphenol F. Type epoxy resin, copolymerized epoxy resin of bisphenol S and bisphenol F, and the like. Among these, a cyanate resin (including a prepolymer of cyanate resin) is particularly preferable. Thereby, the thermal expansion coefficient of the prepreg 10 can be made small. Furthermore, the electrical characteristics (low dielectric constant, low dielectric loss tangent) of the prepreg 10 are also excellent.

  The cyanate resin can be obtained by, for example, reacting a halogenated cyanide compound with a phenol and prepolymerizing it by a method such as heating as necessary. Specific examples include bisphenol type cyanate resins such as novolac type cyanate resin, bisphenol A type cyanate resin, bisphenol E type cyanate resin, and tetramethylbisphenol F type cyanate resin. Among these, novolac type cyanate resin is preferable. Thereby, the heat resistance improvement by a crosslinking density increase and flame retardance, such as a 1st resin composition, can be improved. This is because the novolac-type cyanate resin forms a triazine ring after the curing reaction. Furthermore, it is considered that novolak-type cyanate resin has a high benzene ring ratio due to its structure and is easily carbonized. Furthermore, even when the prepreg 10 is thinned (thickness of 35 μm or less), excellent rigidity can be imparted to the prepreg 10. In particular, since the rigidity during heating is excellent, the reliability when mounting a semiconductor element is also particularly excellent.

前記式（Ｉ）で示されるノボラック型シアネート樹脂の平均繰り返し単位ｎは、特に限定されないが、１〜１０が好ましく、特に２〜７が好ましい。平均繰り返し単位ｎが前記下限値未満であるとノボラック型シアネート樹脂は結晶化しやすくなり、汎用溶媒に対する溶解性が比較的低下するため、取り扱いが困難となる場合がある。また、プリプレグ１０を作製した場合にタック性が生じ、プリプレグ１０同士が接触したとき互いに付着したり、樹脂の転写が生じたりする場合がある。平均繰り返し単位ｎが前記上限値を超えると溶融粘度が高くなりすぎ、プリプレグの成形性が低下する場合がある。 As said novolak-type cyanate resin, what is shown, for example by Formula (I) can be used.

The average repeating unit n of the novolak cyanate resin represented by the formula (I) is not particularly limited, but is preferably 1 to 10, and particularly preferably 2 to 7. When the average repeating unit n is less than the lower limit, the novolak cyanate resin is easily crystallized, and the solubility in a general-purpose solvent is relatively lowered, which may make handling difficult. Further, when the prepreg 10 is manufactured, tackiness is generated, and when the prepregs 10 come into contact with each other, they may adhere to each other or transfer of the resin may occur. When the average repeating unit n exceeds the upper limit, the melt viscosity becomes too high, and the moldability of the prepreg may deteriorate.

  The weight average molecular weight of the cyanate resin or the like can be measured by, for example, GPC.

In addition, as said cyanate resin, what prepolymerized this can also be used. That is, the cyanate resin may be used alone, a cyanate resin having a different weight average molecular weight may be used in combination, or the cyanate resin and its prepolymer may be used in combination.
The prepolymer is usually obtained by, for example, trimerizing the cyanate resin by a heat reaction or the like, and is preferably used for adjusting the moldability and fluidity of the resin composition. .
Although it does not specifically limit as said prepolymer, For example, what has a trimerization rate of 20 to 50 weight% can be used. This trimerization rate can be determined using, for example, an infrared spectroscopic analyzer.

  Moreover, when using together the hardening agent or hardening accelerator which improves the adhesiveness mentioned later, other than the curable resin excellent in adhesiveness with the above-mentioned conductive property, for example, a phenol novolak resin, a cresol novolak resin, a bisphenol A novolak Novolak type phenolic resin such as resin, unmodified resol phenolic resin, phenolic resin such as oil-modified resol phenolic resin modified with tung oil, linseed oil, walnut oil, etc., bisphenol A epoxy resin, bisphenol F epoxy Bisphenol type epoxy resin such as resin, novolac epoxy resin, novolac type epoxy resin such as cresol novolac epoxy resin, epoxy resin such as biphenyl type epoxy resin, unsaturated polyester resin, diallyl phthalate resin, silicone resin Or the like can be used.

  Although content of the said curable resin is not specifically limited, 5 to 50 weight% of the whole said 1st resin composition is preferable, and 10 to 40 weight% is especially preferable. When the content is less than the lower limit, it may be difficult to form the prepreg 10, and when the content exceeds the upper limit, the strength of the prepreg 10 may be reduced.

  Examples of curing aids (such as curing agents and curing accelerators) that improve the adhesion to the conductor layer include tertiary amines such as triethylamine, tributylamine, diazabicyclo [2,2,2] octane, and 2-ethyl. -4-ethylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2,4-diamino-6 -[2'-Methylimidazolyl- (1 ')]-ethyl-s-triazine, 2,4-diamino-6- (2'-undecylimidazolyl) -ethyl-s-triazine, 2,4-diamino-6 -[2'-ethyl-4-methylimidazolyl- (1 ')]-ethyl-s-triazine, 1-benzyl-2-phenylimidazole, etc. Imidazole compounds. Among these, an imidazole compound having two or more functional groups selected from an aliphatic hydrocarbon group, an aromatic hydrocarbon group, a hydroxyalkyl group, and a cyanoalkyl group is preferable, and in particular, 2-phenyl-4, 5-dihydroxymethylimidazole is preferred. By using such an imidazole compound, the heat resistance of the resin composition can be improved, and low thermal expansion and low water absorption can be imparted to the resin layer formed from the resin composition.

  In addition, when a curable resin having excellent adhesion is used as the curable resin, in addition to the above-described curing aid for improving the adhesion, for example, zinc naphthenate, cobalt naphthenate, tin octylate, cobalt octylate, bis Organic metal salts such as acetylacetonate cobalt (II) and trisacetylacetonate cobalt (III), phenolic compounds such as phenol, bisphenol A and nonylphenol, organic acids such as acetic acid, benzoic acid, salicylic acid and paratoluenesulfonic acid Can be used.

  Although content of the said hardening adjuvant is not specifically limited, 0.01 to 3 weight% of the whole said 1st resin composition is preferable, and 0.1 to 1 weight% is especially preferable. If the content is less than the lower limit, the effect of promoting curing may not appear, and if the content exceeds the upper limit, the storability of the prepreg 10 may be reduced.

  In addition, it is preferable that the curable resin having excellent adhesion with the conductor layer and the curing aid for improving the adhesion with the conductor layer are used in combination because of the effect of improving the adhesion with the conductor layer. .

The first resin composition preferably contains an inorganic filler. Thereby, even if the prepreg 10 is thinned (thickness of 35 μm or less), it can be excellent in strength. Furthermore, it is possible to improve the low thermal expansion of the prepreg.
Examples of the inorganic filler include talc, alumina, glass, silica, mica, aluminum hydroxide, magnesium hydroxide and the like. Among these, silica is preferable, and fused silica (particularly spherical fused silica) is preferable in that it has excellent low thermal expansion. The shape is crushed and spherical, but in order to reduce the melt viscosity of the resin composition in order to ensure the impregnation of the fiber substrate 1, a method of use that suits the purpose, such as using spherical silica, is adopted. The

The average particle size of the inorganic filler is not particularly limited, but is preferably 0.01 to 5.0 μm, particularly preferably 0.2 to 2.0 μm. If the particle size of the inorganic filler is less than the lower limit value, the viscosity of the varnish increases, which may affect the workability when producing the prepreg 10. When the upper limit is exceeded, phenomena such as sedimentation of the inorganic filler may occur in the varnish. By setting the average particle diameter of the inorganic filler within the above range, the effect of using the inorganic filler is excellent in the balance between the two.
This average particle diameter can be measured, for example, by a particle size distribution meter (manufactured by HORIBA, LA-500).

Furthermore, spherical silica (especially spherical fused silica) having an average particle diameter of 5.0 μm or less is preferable, and spherical fused silica having an average particle diameter of 0.01 to 2.0 μm, most preferably 0.1 to 0.5 μm is particularly preferable. Thereby, the filling property of an inorganic filler can be improved. Further, a dense roughened state can be obtained, and high-density circuit formation is facilitated. Further, it is possible to form a circuit suitable for high-speed signal transmission.
The inorganic filler used in the first resin composition is not particularly limited, but it is preferable that the average particle diameter is smaller than the inorganic filler used in the second resin composition described later. Thereby, it becomes easy to form a dense roughened state.

Further, in order to improve the adhesion to the conductor layer, an acid-soluble inorganic filler may be used as the inorganic filler. Thereby, plating adhesion can be improved.
Examples of the acid-soluble inorganic filler include metal oxides such as calcium carbonate, zinc oxide, and iron oxide.

Moreover, in order to improve adhesiveness with a conductor layer, you may use together the said inorganic filler and organic filler.
Examples of the organic filler include resin fillers such as liquid crystal polymer and polyimide.

  Although content of the said inorganic filler is not specifically limited, 20 to 70 weight% of the whole said 1st resin composition is preferable, and 30 to 60 weight% is especially preferable. If the content of the inorganic filler is less than the lower limit, the effect of imparting low thermal expansion and low water absorption by the inorganic filler may be reduced. Moreover, when the said upper limit is exceeded, a moldability may fall by the fall of the fluidity | liquidity of a resin composition. By making content of the said inorganic filler in the said range, the effect by use of an inorganic filler will be excellent in both balance.

  When a cyanate resin (particularly a novolac-type cyanate resin) is used as the curable resin, it is preferable to use an epoxy resin (substantially free of halogen atoms). Examples of the epoxy resin include phenol novolac type epoxy resins, bisphenol type epoxy resins, naphthalene type epoxy resins, arylalkylene type epoxy resins and the like. Among these, aryl alkylene type epoxy resins are preferable. Thereby, moisture absorption solder heat resistance and a flame retardance can be improved.

  The arylalkylene-type epoxy resin refers to an epoxy resin having one or more arylalkylene groups in a repeating unit. For example, a xylylene type epoxy resin, a biphenyl dimethylene type epoxy resin, etc. are mentioned. Among these, a biphenyl dimethylene type epoxy resin is preferable. The biphenyl dimethylene type epoxy resin can be represented by, for example, the formula (II).

  The average repeating unit n of the biphenyl dimethylene type epoxy resin represented by the formula (II) is not particularly limited, but is preferably 1 to 10, and particularly preferably 2 to 5. When the average repeating unit n is less than the lower limit, the biphenyldimethylene type epoxy resin is easily crystallized, and the solubility in a general-purpose solvent is relatively lowered, which may make handling difficult. Moreover, when the average repeating unit n exceeds the upper limit, the fluidity of the resin is lowered, which may cause molding defects and the like.

  Although content of the said epoxy resin is not specifically limited, 1 to 55 weight% of the whole said 1st resin composition is preferable, and 2 to 40 weight% is especially preferable. If the content is less than the lower limit, the reactivity of the cyanate resin may decrease, or the moisture resistance of the product obtained may decrease, and if the content exceeds the upper limit, the heat resistance may decrease.

The weight average molecular weight of the epoxy resin is not particularly limited, but the weight average molecular weight is preferably 300 to 20,000, and particularly preferably 500 to 5,000. When the weight average molecular weight is less than the lower limit value, tackiness may occur in the prepreg 10, and when the upper limit value is exceeded, the impregnation property to the base material is lowered when the prepreg 10 is produced, and a uniform product cannot be obtained. There is a case.
The weight average molecular weight of the epoxy resin can be measured by GPC, for example.

In addition, a component (including a resin or the like) that improves the adhesion to the conductor layer may be added to the first resin composition. Examples thereof include a phenoxy resin, a polyvinyl alcohol-based resin, and a coupling agent that improves adhesion with the metal constituting the conductor layer.
Examples of the phenoxy resin include a phenoxy resin having a bisphenol skeleton, a phenoxy resin having a naphthalene skeleton, and a phenoxy resin having a biphenyl skeleton. A phenoxy resin having a structure having a plurality of these skeletons can also be used.

  Among these, a phenoxy resin having a biphenyl skeleton and a bisphenol S skeleton can be used. Thereby, the glass transition temperature can be increased due to the rigidity of the biphenyl skeleton, and the adhesion of the plated metal when the multilayer printed wiring board is manufactured can be improved by the bisphenol S skeleton.

  A phenoxy resin having a bisphenol A skeleton and a bisphenol F skeleton can also be used. Thereby, the adhesiveness to an inner-layer circuit board can further be improved at the time of manufacture of a multilayer printed wiring board.

  Further, the phenoxy resin having the biphenyl skeleton and the bisphenol S skeleton and the phenoxy resin having the bisphenol A skeleton and the bisphenol F skeleton are preferably used in combination. Thereby, these characteristics can be expressed with good balance.

  When the phenoxy resin (1) having the bisphenol A skeleton and the bisphenol F skeleton and the phenoxy resin (2) having the biphenyl skeleton and the bisphenol S skeleton are used in combination, the combination ratio (weight) is not particularly limited. For example, (1) :( 2) = 2: 8 to 9: 1 can be set.

  The molecular weight of the phenoxy resin is not particularly limited, but the weight average molecular weight is preferably 5,000 to 70,000, and particularly preferably 10,000 to 60,000. When the weight average molecular weight of the phenoxy resin is less than the lower limit, the effect of improving the film forming property may not be sufficient. On the other hand, if the upper limit value is exceeded, the solubility of the phenoxy resin may decrease. By making the weight average molecular weight of the phenoxy resin within the above range, it is possible to achieve an excellent balance of these characteristics.

  Although content of a phenoxy resin is not specifically limited, It is preferable that it is 1 to 40 weight% of the whole said resin composition, and 5 to 30 weight% is especially preferable. When the content of the phenoxy resin is less than the lower limit, the effect of improving the film forming property may not be sufficient. On the other hand, when the upper limit is exceeded, the content of the cyanate resin is relatively decreased, and thus the effect of imparting low thermal expansion may be reduced. By setting the content of the phenoxy resin within the above range, it is possible to achieve an excellent balance of these characteristics.

The first resin composition is not particularly limited, but it is preferable to use a coupling agent. The coupling agent uniformly fixes the curable resin and the inorganic filler to the sheet-like substrate 1 by improving the wettability of the interface between the curable resin and the inorganic filler, In particular, solder heat resistance after moisture absorption can be improved.
As the coupling agent, it is preferable to use one or more coupling agents selected from, for example, an epoxy silane coupling agent, a titanate coupling agent, an aminosilane coupling agent, and a silicone oil type coupling agent. . Thereby, especially the wettability of the interface of resin and an inorganic filler can be improved, and heat resistance can be improved more.
Although content of the said coupling agent is not specifically limited, It is preferable that it is 0.05-3 weight part with respect to 100 weight part of said inorganic fillers, and 0.1-2 weight part is especially preferable. If the content is less than the lower limit, the inorganic filler cannot be sufficiently coated, and thus the effect of improving the heat resistance may be reduced. If the content exceeds the upper limit, the reaction is affected, and the bending strength is reduced. There is a case. By making content of a coupling agent in the said range, the effect by use of a coupling agent is excellent in both balance.

  In addition to the components described above, the first resin composition may contain additives such as an antifoaming agent, a leveling agent, a pigment, and an antioxidant as necessary.

  Although the thickness of the 1st resin layer 2 comprised with such a 1st resin composition is not specifically limited, 3-15 micrometers is preferable and 5-10 micrometers is especially preferable. When the thickness is within the above range, the thickness of the entire prepreg can be particularly reduced.

  The surface roughness of the first resin layer 2 (after the roughening treatment) is not particularly limited, but is preferably 2 μm or less, particularly preferably 0.5 μm or less. Within the above range, the resist adhesion is particularly excellent even when a fine circuit is formed.

  Examples of the conductor layer formed on the first resin layer 2 include metal foils such as copper foil and aluminum foil, and plated copper. Among these, plated copper is preferable. Thereby, a fine circuit can be easily formed.

(Second resin layer)
As shown in FIG. 1, the second resin layer 3 is formed on the other surface side (lower side in FIG. 1) of the core layer 11. The second resin layer 3 is composed of a second resin composition different from the first resin composition, and is designed to have characteristics (for example, circuit embedding property) different from the first resin layer 2. Here, different resin compositions are different from each other in at least one of the types of resins and fillers constituting the respective resin compositions, the content of the resins and fillers, the molecular weight of the resins, and the like. I need it.
The second resin composition contains, for example, a (thermo) curable resin, a curing agent, a curing accelerator, a filler, and the like.

Examples of the curable resin include novolak type phenol resins such as phenol novolak resin, cresol novolak resin, bisphenol A novolak resin, unmodified resol phenol resin, oil-modified resol phenol resin modified with tung oil, linseed oil, walnut oil, and the like. Phenol resin such as resol type phenol resin, bisphenol type epoxy resin such as bisphenol A epoxy resin, bisphenol F epoxy resin, novolac type epoxy resin such as novolac epoxy resin and cresol novolac epoxy resin, epoxy resin such as biphenyl type epoxy resin , Resin having triazine ring such as urea (urea) resin, melamine resin, unsaturated polyester resin, bismaleimide resin, polyurethane resin, diallyl phthalate resin, silicone Fat, resin having a benzoxazine ring, cyanate resins.
Among these, cyanate resins (including prepolymers of cyanate resins) are particularly preferable. Thereby, the thermal expansion coefficient of the prepreg 10 can be made small. Furthermore, the electrical characteristics (low dielectric constant, low dielectric loss tangent) of the prepreg 10 are also excellent.

  The cyanate resin can be obtained by, for example, reacting a halogenated cyanide compound with a phenol and prepolymerizing it by a method such as heating as necessary. Specific examples include bisphenol type cyanate resins such as novolac type cyanate resin, bisphenol A type cyanate resin, bisphenol E type cyanate resin, and tetramethylbisphenol F type cyanate resin. Among these, novolac type cyanate resin is preferable. Thereby, the heat resistance improvement by a crosslinking density increase and the flame retardance of a 2nd resin composition etc. can be improved. This is because the novolac-type cyanate resin forms a triazine ring after the curing reaction. Furthermore, it is considered that novolak-type cyanate resin has a high benzene ring ratio due to its structure and is easily carbonized. Furthermore, even when the prepreg 10 is thinned (thickness of 35 μm or less), excellent rigidity can be imparted to the prepreg 10. In particular, since the rigidity during heating is excellent, the reliability when mounting a semiconductor element is also particularly excellent.

前記式（Ｉ）で示されるノボラック型シアネート樹脂の平均繰り返し単位ｎは、特に限定されないが、１〜１０が好ましく、特に２〜７が好ましい。平均繰り返し単位ｎが前記下限値未満であるとノボラック型シアネート樹脂は結晶化しやすくなり、汎用溶媒に対する溶解性が比較的低下するため、取り扱いが困難となる場合がある。また、平均繰り返し単位ｎが前記上限値を超えると溶融粘度が高くなりすぎ、プリプレグの成形性が低下する場合がある。 As said novolak-type cyanate resin, what is shown, for example by Formula (I) can be used.

The average repeating unit n of the novolak cyanate resin represented by the formula (I) is not particularly limited, but is preferably 1 to 10, and particularly preferably 2 to 7. When the average repeating unit n is less than the lower limit, the novolak cyanate resin is easily crystallized, and the solubility in a general-purpose solvent is relatively lowered, which may make handling difficult. Moreover, when average repeating unit n exceeds the said upper limit, melt viscosity will become high too much and the moldability of a prepreg may fall.

Although the weight average molecular weight of the cyanate resin is not particularly limited, a weight average molecular weight of 500 to 4,500 is preferable, and 600 to 3,000 is particularly preferable. When the prepreg 10 is produced when the weight average molecular weight is less than the lower limit, tackiness may occur, and when the prepregs 10 come into contact with each other, they may adhere to each other or transfer of the resin may occur. Further, when the weight average molecular weight exceeds the upper limit, the reaction becomes too fast, and when a substrate (particularly, a circuit substrate) is formed, molding defects may occur or the interlayer peel strength may be lowered.
The weight average molecular weight of the cyanate resin or the like can be measured by, for example, GPC.
Moreover, you may use together cyanate resin from which a weight average molecular weight differs as said cyanate resin. Thereby, the tack may be improved.

  Although content of the said curable resin is not specifically limited, 5 to 50 weight% of the whole said 2nd resin composition is preferable, and 20 to 40 weight% is especially preferable. When the content is less than the lower limit, it may be difficult to form the prepreg 10, and when the content exceeds the upper limit, the strength of the prepreg 10 may be reduced.

Moreover, it is preferable that the said 2nd resin composition contains an inorganic filler. Thereby, even if the prepreg 10 is thinned (thickness of 35 μm or less), it can be excellent in strength. Furthermore, it is possible to improve the low thermal expansion of the prepreg.
Examples of the inorganic filler include talc, alumina, glass, silica, mica, aluminum hydroxide, magnesium hydroxide and the like. Among these, silica is preferable, and fused silica (particularly spherical fused silica) is preferable in that it has excellent low thermal expansion. The shape is crushed and spherical, but in order to reduce the melt viscosity of the resin composition in order to ensure the impregnation of the fiber substrate 1, a method of use that suits the purpose, such as using spherical silica, is adopted. The

The average particle size of the inorganic filler is not particularly limited, but is preferably 0.01 to 5.0 μm, particularly preferably 0.2 to 2.0 μm. If the particle size of the inorganic filler is less than the lower limit value, the viscosity of the varnish increases, which may affect the workability when producing the prepreg 10. When the upper limit is exceeded, phenomena such as sedimentation of the inorganic filler may occur in the varnish.
This average particle diameter can be measured, for example, by a particle size distribution meter (manufactured by HORIBA, LA-500).

  Furthermore, spherical silica (especially spherical fused silica) having an average particle size of 5.0 μm or less is preferable, and spherical fused silica having an average particle size of 0.01 to 2.0 μm is particularly preferable. Thereby, the filling property of an inorganic filler can be improved.

  Although content of the said inorganic filler is not specifically limited, 40 to 80 weight% of the whole said 2nd resin composition is preferable, and 50 to 70 weight% is especially preferable. When the content is within the above range, particularly low thermal expansion and low water absorption can be achieved.

  When a cyanate resin (particularly a novolac-type cyanate resin) is used as the curable resin, it is preferable to use an epoxy resin (substantially free of halogen atoms). Examples of the epoxy resin include phenol novolac type epoxy resins, bisphenol type epoxy resins, naphthalene type epoxy resins, arylalkylene type epoxy resins and the like. Among these, aryl alkylene type epoxy resins are preferable. Thereby, moisture absorption solder heat resistance and a flame retardance can be improved.

  The arylalkylene-type epoxy resin refers to an epoxy resin having one or more arylalkylene groups in a repeating unit. For example, a xylylene type epoxy resin, a biphenyl dimethylene type epoxy resin, etc. are mentioned. Among these, a biphenyl dimethylene type epoxy resin is preferable. The biphenyl dimethylene type epoxy resin can be represented by, for example, the formula (II).

  The average repeating unit n of the biphenyl dimethylene type epoxy resin represented by the formula (II) is not particularly limited, but is preferably 1 to 10, and particularly preferably 2 to 5. When the average repeating unit n is less than the lower limit, the biphenyldimethylene type epoxy resin is easily crystallized, and the solubility in a general-purpose solvent is relatively lowered, which may make handling difficult. Moreover, when the average repeating unit n exceeds the upper limit, the fluidity of the resin is lowered, which may cause molding defects and the like.

  Although content of the said epoxy resin is not specifically limited, 1 to 55 weight% of the whole said 2nd resin composition is preferable, and 2 to 40 weight% is especially preferable. If the content is less than the lower limit, the reactivity of the cyanate resin may decrease, or the moisture resistance of the product obtained may decrease, and if the content exceeds the upper limit, the heat resistance may decrease.

The weight average molecular weight of the epoxy resin is not particularly limited, but a weight average molecular weight of 500 to 20,000 is preferable, and 800 to 15,000 is particularly preferable. When the weight average molecular weight is less than the lower limit value, tackiness may occur in the prepreg 10, and when the upper limit value is exceeded, the impregnation property to the base material is lowered when the prepreg 10 is produced, and a uniform product cannot be obtained. There is a case.
The weight average molecular weight of the epoxy resin can be measured by GPC, for example.

  When using cyanate resin (especially novolak-type cyanate resin) as said thermosetting resin, it is preferable to use a phenol resin. Examples of the phenol resin include novolak-type phenol resins, resol-type phenol resins, and arylalkylene-type phenol resins. Among these, arylalkylene type phenol resins are preferable. Thereby, moisture absorption solder heat resistance can be improved further.

前記式（III）で示されるビフェニルジメチレン型フェノール樹脂の繰り返し単位ｎは、特に限定されないが、１〜１２が好ましく、特に２〜８が好ましい。平均繰り返し単位ｎが前記下限値未満であると耐熱性が低下する場合がある。また、前記上限値を超えると他の樹脂との相溶性が低下し、作業性が低下する場合がある。 Examples of the aryl alkylene type phenol resin include a xylylene type phenol resin and a biphenyl dimethylene type phenol resin. The biphenyl dimethylene type phenol resin can be represented by, for example, the formula (III).

Although the repeating unit n of the biphenyl dimethylene type phenol resin represented by the formula (III) is not particularly limited, 1 to 12 is preferable, and 2 to 8 is particularly preferable. If the average repeating unit n is less than the lower limit, the heat resistance may be lowered. Moreover, when the said upper limit is exceeded, compatibility with other resin will fall and workability | operativity may fall.

  By combining the above-described cyanate resin (particularly novolac-type cyanate resin) and arylalkylene-type phenol resin, the crosslink density can be controlled and the adhesion between the metal and the resin can be improved.

  Although content of the said phenol resin is not specifically limited, 1 to 55 weight% of the whole said 2nd resin composition is preferable, and 5 to 40 weight% is especially preferable. If the content is less than the lower limit, the heat resistance may be reduced, and if the content exceeds the upper limit, the characteristics of low thermal expansion may be impaired.

The weight average molecular weight of the phenol resin is not particularly limited, but a weight average molecular weight of 400 to 18,000 is preferable, and 500 to 15,000 is particularly preferable. When the weight average molecular weight is less than the lower limit value, tackiness may occur in the prepreg 10, and when the upper limit value is exceeded, the impregnation property to the fiber base material 1 is reduced when the prepreg 10 is manufactured, and a uniform product is obtained. It may not be possible.
The weight average molecular weight of the phenol resin can be measured by, for example, GPC.

  Furthermore, the cyanate resin (especially novolac type cyanate resin), the phenol resin (arylalkylene type phenolic resin, particularly biphenyldimethylene type phenolic resin) and the epoxy resin (arylalkylene type epoxy resin, particularly biphenyldimethylene type epoxy resin). When a board (especially a circuit board) is produced using a combination with the above, particularly excellent dimensional stability can be obtained.

The second resin composition is not particularly limited, but it is preferable to use a coupling agent. The coupling agent uniformly fixes the curable resin and the inorganic filler to the sheet-like substrate 1 by improving the wettability of the interface between the curable resin and the inorganic filler, In particular, solder heat resistance after moisture absorption can be improved.
As the coupling agent, any commonly used one can be used. Specifically, an epoxy silane coupling agent, a cationic silane coupling agent, an aminosilane coupling agent, a titanate coupling agent, and a silicone oil type coupling. It is preferable to use one or more coupling agents selected from among the agents. Thereby, the wettability with the interface of an inorganic filler can be made high, and thereby heat resistance can be improved more.

  The addition amount of the coupling agent is not particularly limited because it depends on the surface area of the inorganic filler, but is preferably 0.05 to 3 parts by weight, particularly 0.1 to 2 parts by weight with respect to 100 parts by weight of the inorganic filler. Part is preferred. If the content is less than the lower limit, the inorganic filler cannot be sufficiently coated, and thus the effect of improving the heat resistance may be reduced. If the content exceeds the upper limit, the reaction is affected, and the bending strength is reduced. There is a case.

  A curing accelerator may be used in the second resin composition as necessary. A well-known thing can be used as said hardening accelerator. For example, organic metal salts such as zinc naphthenate, cobalt naphthenate, tin octylate, cobalt octylate, bisacetylacetonate cobalt (II), trisacetylacetonate cobalt (III), triethylamine, tributylamine, diazabicyclo [2,2 , 2] tertiary amines such as octane, 2-phenyl-4-methylimidazole, 2-ethyl-4-ethylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4-methyl-5-hydroxyimidazole Imidazoles such as 2-phenyl-4,5-dihydroxyimidazole, phenolic compounds such as phenol, bisphenol A, and nonylphenol, organic acids such as acetic acid, benzoic acid, salicylic acid, paratoluenesulfonic acid, and the like, or a mixture thereof. .

  Although content of the said hardening accelerator is not specifically limited, 0.05 to 5 weight% of the whole said 2nd resin composition is preferable, and 0.2 to 2 weight% is especially preferable. If the content is less than the lower limit, the effect of promoting curing may not appear, and if the content exceeds the upper limit, the storability of the prepreg 10 may be reduced.

In the first resin composition, a thermoplastic resin such as a phenoxy resin, a polyimide resin, a polyamideimide resin, a polyphenylene oxide resin, or a polyethersulfone resin may be used in combination.
Moreover, you may add additives other than the said components, such as a pigment and antioxidant, to the said 2nd resin composition as needed.

The thickness of the second resin layer 3 is not particularly limited because it depends on the thickness of the inner layer circuit to be joined, but the thickness of t2 represented by the following formula 1) is 0.1 to 5 μm. In particular, it is preferably 1 to 3 μm. When the thickness is within the above range, the embedding property of the inner layer circuit is particularly excellent, and the entire thickness can be reduced.
Formula 1) B = t1 × (1-S / 100) + t2
Here, the thickness of the second resin layer 3 is set to B [μm], the thickness of the inner layer circuit 4 is set to t1 [μm] and the remaining copper ratio is set to S, and the second resin layer starts from the upper end portion 41 of the inner layer circuit 4. 3 is t2 (FIG. 2).

  The thermal expansion coefficient in the plane (X, Y) direction of the second resin layer 3 is not particularly limited, but is preferably 20 ppm or less, and particularly preferably 5 to 16 ppm. When the thermal expansion coefficient is within the above range, the connection reliability and the mounting reliability of a semiconductor element and the like are particularly excellent.

  Next, such a prepreg 10 manufactures, for example, a carrier material 2a obtained by applying the first resin composition to the carrier film and a carrier material 3a obtained by applying the second resin composition to the carrier film, and these carrier materials 2a, After laminating 3a on the sheet-like substrate 1, the prepreg 10 in which the resin composition constituting each resin layer is different on both surfaces of the prepreg 10 can be obtained by peeling the carrier film.

Here, a method of manufacturing carrier materials 2a and 3a in which a resin composition is previously applied to a carrier film, laminating the carrier materials 2a and 3a on the sheet-like substrate 1, and then peeling the carrier film is shown in FIG. This will be specifically described with reference to FIG. FIG. 3 is a process diagram showing an example of a process for producing the prepreg of the present invention.
First, a carrier material 2a having the first resin layer 2 composed of the first resin composition as described above and a carrier material 3a having the second resin layer 3 composed of the second resin composition as described above. prepare.
The carrier materials 2a and 3a can be obtained by, for example, a method of applying a varnish of the first resin composition and the second resin composition to a carrier film.

  Next, using the vacuum laminating apparatus 8, the carrier materials 2 a and 3 a are overlapped from both surfaces of the sheet-like substrate 1 under reduced pressure, and are joined by the laminating roll 81. By joining under reduced pressure, even if there is an unfilled portion in the inside of the sheet-like base material 1 or in the joining portion between each carrier material 2a, 3a and the sheet-like base material 1, this is reduced by a reduced-pressure void or substantially It can be a vacuum void. Therefore, the finally obtained prepreg 10 does not generate voids and can be in a good molded state. This is because the decompression void or the vacuum void can be removed by a heat treatment described later. As another apparatus for joining the sheet-like substrate 1 and the carrier materials 2a and 3a under such a reduced pressure, for example, a vacuum box apparatus or the like can be used.

Next, after joining the sheet-like base material 1 and each carrier material 2a, 3a, it heat-processes with the hot air drying apparatus 9 at the temperature more than the melting temperature of the resin composition which comprises each carrier material 2a, 3a. Thereby, the decompression void etc. which have occurred in the joining process under the decompression can be erased.
The other heat treatment method can be carried out using, for example, an infrared heating device, a heating roll device, a flat platen hot platen press device, or the like.

According to the above-described method, the prepreg 10 can be easily obtained even when the sheet-like substrate 1 having a thickness of 25 μm or less is used. In a conventional prepreg manufacturing method (for example, a method in which a sheet-like base material is dipped into a resin varnish and dried using a normal coating apparatus), a resin material is supported on a sheet-like base material having a thickness of 30 μm or less. It was difficult to obtain a prepreg. That is, when a sheet-like substrate having a small thickness is immersed in a thermosetting resin and passed through a large number of transport rolls, or when adjusting the amount of resin material impregnated into the sheet-like substrate, the sheet-like substrate Stress may act on the sheet, and the sheet-like substrate may be opened (enlarged), or the sheet-like substrate may be cut off when taken off.
On the other hand, in the above-described method, the carrier materials 2a and 3a can be supported even on the sheet-like base material 1 having a thickness of 25 μm or less, thereby adding to the prepreg 10 having a normal thickness The prepreg 10 having a thickness of 35 μm or less can be easily obtained. Further, the thickness of the prepreg 10 after forming the substrate can be made 35 μm or less between the conductor circuit layers. If the thickness between the conductor circuit layers can be 35 μm or less, the thickness of the finally obtained substrate can be reduced.

  Moreover, as another method of obtaining such a prepreg 10, for example, it is immersed in a low-viscosity resin varnish on one side of the sheet-like substrate 1, dried to form the first resin layer 2, and another resin. The prepreg 10 can also be obtained by immersing in a varnish to form the second resin layer 3.

  In the prepreg 10 thus obtained, the sheet-like substrate 1 may be unevenly distributed with respect to the thickness direction of the prepreg 10 as shown in FIG. Thereby, the amount of resin can be adjusted according to a circuit pattern.

  Here, the state where the core layer 11 mainly composed of the sheet-like base material 1 is unevenly distributed in the thickness direction of the prepreg 10 will be described with reference to FIG. 4A and 4B are cross-sectional views schematically showing a state in which the core layer 11 is unevenly distributed with respect to the prepreg 10. As shown in FIGS. 4A and 4B, the center of the core layer 11 (sheet-like base material 1) is shifted from the center line AA in the thickness direction of the prepreg 10. Means. In FIG. 4A, the lower surface (lower side in FIG. 4) of the core layer 11 (sheet-like base material 1) almost coincides with the lower surface (lower side in FIG. 4) of the prepreg 10. It has become. In FIG.4 (b), the core layer 11 is arrange | positioned between the centerline AA and the lower surface (lower side in FIG. 4) of the prepreg 10. In FIG. The core layer 11 may partially overlap the center line AA.

The thermal expansion coefficient in the plane direction of such a prepreg 10 is not particularly limited, but is preferably 16 ppm or less, and particularly preferably 5 to 10 ppm. When the thermal expansion coefficient is within the above range, the crack resistance against repeated thermal shock can be improved.
The thermal expansion coefficient in the surface direction can be evaluated by increasing the temperature at 10 ° C./min using, for example, a TMA apparatus (manufactured by TA Instruments).

  The thickness of such a prepreg 10 is not particularly limited, but is preferably 20 to 80 μm, and more preferably 30 to 60 μm. When the thickness is within the above range, the thickness of the finally obtained substrate can be particularly reduced.

Next, the substrate and the semiconductor device will be described.
As shown in FIG. 5, the substrate 100 includes a core substrate 101, three layers of prepregs (10 a, 10 b, 10 c) provided on the upper side of the core substrate 101 (upper side in FIG. 5), and a lower side of the core substrate 101. 3 layers of prepregs (10d, 10e, 10f) provided on the side (lower side in FIG. 5). A predetermined circuit wiring portion 42 is formed between the core substrate 101 and the prepregs 10a and 10b and between the prepregs (10a and 10b, 10b and 10c, 10d and 10e, and 10e and 10f). A pad portion 5 is provided on the surfaces of the prepregs 10c and 10f. It is preferable to use the prepreg 10 having a thickness of 35 μm or less as described above for at least one (preferably all) of the prepregs 10a to 10f. Thereby, the thickness of the (circuit) substrate 100 can be reduced.
Each circuit wiring portion 42 is electrically connected through a filled via portion 6 provided so as to penetrate through the prepregs 10a to 10f.

Each of the prepregs 10a to 10f constituting the substrate 100 is provided on the side where the circuit wiring part 42 (conductor layer) is formed (the upper side in FIG. 5 of each prepreg 10a to 10c and the lower side in FIG. 5 of 10d to 10f). The first resin composition constituting the first resin layer 2 is different from the second resin composition constituting the second resin layer 3 on the opposite side. The 1st resin composition which comprises the 1st resin layer 2 has become a composition which improves adhesiveness with a conductor layer. Thereby, the 1st resin layer 2 is excellent in adhesiveness with a conductor layer. Further, the second resin composition constituting the second resin layer 3 has a composition that improves the embedding property of the circuit wiring part 42. Further, the second resin layer 3 has a composition that can achieve low thermal expansion.
Further, the thickness of the first resin layer 2 is set to a minimum thickness necessary for improving the adhesion to the conductor layer, and the thickness of the second resin layer 3 is set to a minimum thickness necessary for embedding the circuit wiring portion. The thickness of the substrate 100 can be reduced by adjusting so as to be.

  Further, the semiconductor device 200 can be obtained by mounting the semiconductor element 7 by connecting the bump 71 of the semiconductor element 7 and the pad portion 5 of the substrate 100 to the substrate 100 as shown in FIG. 5 (FIG. 6). . In such a semiconductor device 7, the thicknesses of the first resin layer 2 and the second resin layer 3 constituting the prepregs 10 a to 10 f constituting the substrate 100 can be adjusted to optimum thicknesses. Thus, the semiconductor device 200 having the minimum thickness necessary for the required characteristics can be obtained.

Although FIGS. 5 and 6 describe a six-layer substrate, the substrate of the present invention is not limited to this, and is also suitable for a multilayer substrate of three layers, four layers, five layers, or seven layers, eight layers, etc. Can be used.
Moreover, in the board | substrate 100 of this invention, the prepreg 10 from which the 1st resin composition which comprises the 1st resin layer 2 as mentioned above and the 2nd resin composition which comprises the 2nd resin layer 3 differ, and was used conventionally. You may use together with the prepreg currently made.

EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example and a comparative example, this invention is not limited to this. First, an example of a prepreg will be described.
(Example 1)
1. Preparation of first resin layer varnish Cyanate resin (Lonza Japan, Primaset PT-30, weight average molecular weight about 2,600) 24% by weight, biphenyldimethylene type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., NC-3000, epoxy equivalent 275) 24% by weight, phenoxy resin is a copolymer of bisphenol A type epoxy resin and bisphenol F type epoxy resin, and the terminal part is a phenoxy resin having an epoxy group (Japan epoxy resin) 11.8% by weight manufactured by the company, EP-4275, weight average molecular weight 60,000), 0.2 weight by weight of imidazole compound (manufactured by Shikoku Kasei Kogyo Co., Ltd., “2-phenyl-4,5-dihydroxymethylimidazole”) as a curing catalyst % Was dissolved in methyl ethyl ketone. Furthermore, spherical fused silica (manufactured by Admatechs, SO-25H, average particle size 0.5 μm) 39.8% by weight as an inorganic filler and epoxy silane type coupling agent (Nihon Unicar Co., Ltd., A-187) 0. 2% by weight was added and stirred for 60 minutes using a high-speed stirrer to prepare a resin varnish having a solid content of 60% by weight.

2. Preparation of varnish of second resin layer 15% by weight of novolak cyanate resin (Lonza Japan Co., Ltd., Primaset PT-30, weight average molecular weight of about 2,600) as thermosetting resin, biphenyldimethylene type epoxy resin as epoxy resin (Nippon Kayaku Co., Ltd., NC-3000, epoxy equivalent 275) 8.7% by weight, phenol resin biphenyldimethylene type phenol resin (Nippon Kayaku Co., Ltd., GPH-65, hydroxyl group equivalent 200) 6.3% by weight Was dissolved in methyl ethyl ketone. Further, 69.7% by weight of spherical fused silica (manufactured by Admatechs, SO-25H, average particle size 0.5 μm) as an inorganic filler and epoxysilane type coupling agent (manufactured by Nihon Unicar Co., Ltd., A-187) 0. 3 wt% was added, and the mixture was stirred for 60 minutes using a high-speed stirrer to prepare a varnish for the second resin layer having a solid content of 60 wt%.

3. Production of carrier material A polyethylene terephthalate film (manufactured by Mitsubishi Chemical Polyester Co., Ltd., SFB-38, thickness 38 μmm, width 480 mm) was used as a carrier film, and the above-mentioned first resin layer varnish was applied with a comma coater device, 170 ° C. The carrier material 2a (finally the first resin layer is finally formed) is formed by drying for 3 minutes using a drying apparatus, so that the resin layer having a thickness of 9 μm and a width of 410 mm is positioned at the center in the width direction of the carrier film. Obtained.
Further, the amount of the varnish of the second resin layer to be coated by the same method is adjusted so that the resin layer having a thickness of 14 μm and a width of 360 mm is positioned at the center in the width direction of the carrier film. 3a (finally formed second resin layer) was obtained.

4). Production of Prepreg A glass woven fabric (cross type # 1015, width 360 mm, thickness 15 μm, basis weight 17 g / m ² ) was used as a fiber base material, and a prepreg was produced by the vacuum laminating apparatus and hot air drying apparatus shown in FIG.
Specifically, each of the glass woven fabrics is superposed on each other so that the carrier material 2a and the carrier material 3a are located in the center in the width direction of the glass woven fabric, and a laminate roll at 80 ° C. under reduced pressure of 1330 Pa. Was used for bonding.
Here, in the inner region of the width direction dimension of the glass woven fabric, the resin layers of the carrier material 2a and the carrier material 3a are respectively bonded to both sides of the fiber cloth, and in the outer region of the width direction dimension of the glass woven fabric. The resin layers of the carrier material 2a and the carrier material 3a were joined together.
Next, the bonded material was heat-treated without applying pressure by passing it through a horizontal conveying type hot air drying device set at 120 ° C. for 2 minutes to obtain a thickness of 30 μm (first resin layer: 5 μm, A prepreg having a fiber base material of 15 μm and a second resin layer of 10 μm was obtained.

(Example 2)
The same procedure as in Example 1 was performed except that the following varnish was used as the first resin layer.
Without using cyanate resin as thermosetting resin, 24 wt% of biphenyldimethylene type epoxy resin (Nippon Kayaku Co., Ltd., NC-3000, epoxy equivalent 275) as epoxy resin, liquid bisphenol type epoxy resin (Dainippon Ink Co., Ltd.) Manufactured by 830S) and a copolymer of bisphenol S epoxy resin as a phenoxy resin and having a terminal phenoxy resin (manufactured by Japan Epoxy Resin, YX-8100, weight) 18 wt% of an average molecular weight of 30,000) and 0.2 wt% of an imidazole compound (“2-phenyl-4,5-dihydroxymethylimidazole” manufactured by Shikoku Kasei Kogyo Co., Ltd.) as a curing catalyst were dissolved in methyl ethyl ketone. Furthermore, spherical fused silica (manufactured by Admatechs, SO-25H, average particle size 0.5 μm) 39.8% by weight as an inorganic filler and epoxy silane type coupling agent (Nihon Unicar Co., Ltd., A-187) 0. 2% by weight was added and stirred for 60 minutes using a high-speed stirrer to prepare a resin varnish having a solid content of 60% by weight.
The thickness of the obtained prepreg was 30 μm (first resin layer: 5 μm, fiber substrate: 15 μm, second resin layer: 10 μm).

(Example 3)
The same procedure as in Example 1 was performed except that the following varnish was used as the second resin layer.
Biphenyldimethylene type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., NC-3000, epoxy equivalent 275) 17.5% by weight as a thermosetting resin, biphenyldimethylene type phenol resin (manufactured by Nippon Kayaku Co., Ltd.) as a phenol resin , GPH-65, hydroxyl group equivalent 200) 12% by weight, imidazole (manufactured by Shikoku Kasei Co., Ltd., 2P4MHZ) 0.5% by weight and an epoxysilane coupling agent (Nihon Unicar Co., Ltd., A-187) as a coupling agent, 0.3 part by weight with respect to 100 parts by weight of inorganic filler to be described later is dissolved in methyl ethyl ketone at room temperature, and spherical fused silica SFP-10X (manufactured by Denki Kagaku Kogyo Co., Ltd., average particle size 0.3 μm) 20 weight as inorganic filler. % And 50% by weight of spherical fused silica SO-32R (manufactured by Admatechs, average particle size 1.5 μm) The mixture was stirred for 10 minutes using a high-speed stirrer to prepare a varnish for the second resin layer.
The thickness of the obtained prepreg was 30 μm (first resin layer: 5 μm, fiber substrate: 15 μm, second resin layer: 10 μm).

Example 4
The thickness of the resin layer of the carrier material 2a and the carrier material 3a was the same as that of Example 1 except that the thickness was 14 μm (carrier material 1) and 14 μm (carrier material 2), respectively. The thickness of the obtained prepreg was 35 μm (first resin layer: 10 μm, fiber substrate: 15 μm, second resin layer: 10 μm).

(Example 5)
The same procedure as in Example 1 was conducted except that the fiber base material and the carrier materials 2a and 3a were changed as follows.
A glass woven fabric (cross type # 1037, thickness 24 μm, basis weight 24 g / m ² ) was used as the fiber base material. The thickness of the obtained prepreg was 40 μm (first resin layer: 5 μm, fiber substrate: 24 μm, second resin layer: 11 μm). The thicknesses of the resin layers of the carrier material 2a and the carrier material 3a were 12 μm (carrier material 2a) and 18 μm (carrier material 3a), respectively.

(Example 6) Example using thick fiber base material The same procedure as in Example 1 was conducted except that the fiber base material and carrier materials 2a and 3a were as follows.
A glass woven fabric (cross type # 1080, thickness 42 μm, basis weight 48 g / m ² ) was used as the fiber base material. The thicknesses of the resin layers of the carrier material 2a and the carrier material 3a were 20 μm (carrier material 2a) and 22 μm (carrier material 3a), respectively. The thickness of the obtained prepreg was 60 μm (first resin layer: 8 μm, fiber substrate: 42 μm, second resin layer: 10 μm).

(Comparative Example 1)
1. Adjustment of resin layer varnish Cyanate resin (manufactured by Lonza Japan, Primaset PT-30, weight average molecular weight of about 2,600) 24% by weight as thermosetting resin, biphenyldimethylene type epoxy resin (Nippon Kayaku) as epoxy resin NC-3000, epoxy equivalent 275) 24% by weight, a phenoxy resin, a copolymer of a bisphenol A type epoxy resin and a bisphenol F type epoxy resin, and a terminal part having an epoxy group ( Made by Japan Epoxy Resin Co., Ltd. EP-4275, weight average molecular weight 60,000 11.8% by weight, imidazole compound as a curing catalyst (Shikoku Kasei Kogyo Co., Ltd. “2-phenyl-4,5-dihydroxymethylimidazole”) 0 2% by weight was dissolved in methyl ethyl ketone. Furthermore, spherical fused silica (manufactured by Admatechs, SO-25H, average particle size 0.5 μm) 39.8% by weight as an inorganic filler and epoxy silane type coupling agent (Nihon Unicar Co., Ltd., A-187) 0. 2% by weight was added and stirred for 60 minutes using a high-speed stirrer to prepare a resin varnish having a solid content of 60% by weight.

2. Manufacture of carrier material A polyethylene terephthalate film (manufactured by Mitsubishi Chemical Polyester Co., Ltd., SFB-38, thickness 38 μmm, width 480 mm) is used as a carrier film. The substrate was dried for 3 minutes, and a carrier layer 2a (finally formed with the first resin layer) was obtained by forming a resin layer having a thickness of 9 μm and a width of 410 mm so as to be positioned at the center in the width direction of the carrier film. .
Further, by adjusting the amount of varnish of the resin layer to be applied by the same method, a resin layer having a thickness of 14 μm and a width of 360 mm is formed so as to be positioned at the center in the width direction of the carrier film, and the carrier material 3a ( Finally, a second resin layer was formed). The resin compositions constituting the first resin layer and the second resin layer were the same.

3. Production of Prepreg Using a glass woven fabric (cross type # 1015, width 360 mm, thickness 15 μm, basis weight 17 g / m ² ) as a fiber substrate, a prepreg was produced by a vacuum laminating apparatus and a hot air drying apparatus shown in FIG.
Specifically, each of the glass woven fabrics is superposed on each other so that the carrier material 2a and the carrier material 3a are located in the center in the width direction of the glass woven fabric, and a laminate roll at 80 ° C. under reduced pressure of 1330 Pa. Was used for bonding.
Here, in the inner region of the width direction dimension of the glass woven fabric, the resin layers of the carrier material 2a and the carrier material 3a are respectively bonded to both sides of the fiber cloth, and in the outer region of the width direction dimension of the glass woven fabric. The resin layers of the carrier material 2a and the carrier material 3a were joined together.
Next, the bonded material was heat-treated without applying pressure by passing it through a horizontal conveying type hot air drying device set at 120 ° C. for 2 minutes to obtain a thickness of 30 μm (first resin layer: 5 μm, A prepreg having a fiber base material of 15 μm and a second resin layer of 10 μm was obtained.
(Comparative Example 2)
It was made to be the same as that of the comparative example 1 except having used the following as a thermosetting resin.
15% by weight of novolak cyanate resin (Lonza Japan, Primaset PT-30, weight average molecular weight of about 2,600) as thermosetting resin, biphenyldimethylene type epoxy resin (Nippon Kayaku, NC) as epoxy resin -3000, epoxy equivalent 275) 8.7% by weight, and 6.3% by weight of biphenyl dimethylene type phenolic resin (manufactured by Nippon Kayaku Co., Ltd., GPH-65, hydroxyl equivalent 200) as phenolic resin was dissolved in methyl ethyl ketone. Further, 69.7% by weight of spherical fused silica (manufactured by Admatechs, SO-25H, average particle size 0.5 μm) as an inorganic filler and epoxysilane type coupling agent (manufactured by Nihon Unicar Co., Ltd., A-187) 0. 3 wt% was added, and the mixture was stirred for 60 minutes using a high-speed stirrer to prepare a resin varnish having a solid content of 60 wt%.

(Comparative Example 3)
It was made to be the same as that of the comparative example 1 except having used the following as a thermosetting resin.
As a thermosetting resin, 100 parts by weight of an epoxy resin (Japan Epoxy Resin, EP-5048), 2 parts by weight of a curing agent (dicyandiamide) and 0.1 part by weight of a curing accelerator (2-ethyl-4-methylimidazole) A resin varnish was obtained by dissolving in 100 parts by weight of methyl cellosolve.

  Next, fabrication of a substrate (multilayer substrate) and a semiconductor device using the prepregs obtained in the respective examples and comparative examples will be described.

  A prepreg obtained in each example and comparative example is stacked on a core substrate having a comb-shaped pattern with a conductor spacing of 50 μm on the surface, a circuit thickness of 12 μm and a residual copper ratio of 50%, and a copper foil is further stacked on the outermost layer. Then, heating and pressure molding (3 MPa, 200 ° C., 90 minutes) were performed to obtain a multilayer substrate. Then, after forming a circuit on the outermost copper foil (thickness 12 μm), a semiconductor element was mounted to obtain a semiconductor device.

The following evaluation was performed on the substrate (multilayer substrate) and the semiconductor device obtained in each example and comparative example. The evaluation contents are shown together with the items. The obtained results are shown in Table 1.
1. Interlayer thickness Interlayer thickness (from the upper part of the inner layer circuit to the lower part of the outer layer circuit) was measured from the cross section of the obtained substrate (multilayer substrate).
2. Th2 Thickness t2 thickness (thickness from the upper end portion 41 of the inner layer circuit 4 to the upper end portion 31 of the second resin layer 3) was measured from the cross section of the obtained substrate (multilayer substrate). In addition, the difference from the design value is shown.
3. Formability The cross section of the obtained substrate comb pattern portion was observed with a microscope to evaluate the moldability of the resin layer. Each code is as follows.
○: All samples were excellent in moldability.
Δ: Part of circuit wiring contact with glass woven fabric.
X: The resin layer is not sufficiently embedded, and there are voids and the like.
4). Plating adhesion of first resin layer Adhesion was evaluated by plating copper peel strength.
○: 0.6 kN / m or more ×: Less than 0.6 kN / m Insulation reliability After making a four-layer printed wiring board for insulation reliability test having a comb pattern with a conductor spacing of 50 μm on the inner and outer layers, and measuring these insulation resistances with an automatic super insulation resistance meter (manufactured by ADVANTEST) In a PCT-130 ° C / 85% atmosphere, a DC voltage of 50 V was applied, and the insulation resistance after 96 hours was measured. The applied voltage at the time of measurement was 100 V for 1 minute, and an insulation resistance of 1 × 10 ⁹ Ω or higher was regarded as acceptable.
6). Connection reliability (temperature cycle (TC) test)
Ten daisy chain type evaluation semiconductor devices for connecting a semiconductor element and a substrate through 300 bumps were produced.
After confirming the continuity of the semiconductor device for evaluation described above, a temperature cycle (TC) test was performed in which one cycle was 10 minutes at -50 ° C and 10 minutes at 125 ° C. The number of defective disconnections after 1000 cycles of the TC test was evaluated.

  As is clear from Table 1, the multilayer substrates and semiconductor devices of Examples 1 to 6 were excellent in moldability and plating adhesion, which are difficult to achieve with a thin material. In addition, since the thermosetting resin having excellent moldability and low thermal expansion was disposed in the second insulating layer, a prepreg having excellent insulation reliability of the multilayer substrate and connection reliability as a semiconductor device could be obtained.

FIG. 1 is a cross-sectional view schematically showing an example of the prepreg of the present invention. FIG. 2 is a cross-sectional view schematically showing an example of the prepreg of the present invention. FIG. 3 is a process diagram showing an example of a process for producing the prepreg of the present invention. FIG. 4 is a cross-sectional view schematically showing a state in which the fiber base material is unevenly distributed in the thickness direction of the prepreg. FIG. 5 is a cross-sectional view showing an example of the substrate of the present invention. FIG. 6 is a cross-sectional view showing an example of a semiconductor device of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sheet-like base material 11 Core layer 2 1st resin layer 2a Carrier material 3 2nd resin layer 3a Carrier material 31 Upper end part of 2nd resin layer 4 Inner layer circuit 41 Upper end part of inner layer circuit 42 Circuit wiring part 5 Pad part 6 Filled via Part 7 Semiconductor element 71 Bump 8 Vacuum laminating device 81 Laminating roll 9 Hot air drying device 10 Prepreg 10a Prepreg 10b Prepreg 10c Prepreg 10d Prepreg 10e Prepreg 10f Prepreg 100 Substrate 101 Core substrate 200 Semiconductor device

Claims (13)

A core layer of a sheet-like substrate; a first resin layer formed on one side of the core layer; and a second resin layer formed on the other side; and a conductor layer on the first resin layer A prepreg formed and used,
A prepreg characterized in that a first resin composition constituting the first resin layer and a second resin composition constituting the second resin layer are different.   The prepreg according to claim 1, wherein when a conductor layer is bonded to the first resin layer, a peel strength between the first resin layer and the conductor layer is 0.5 kg / cm or more.   The prepreg according to claim 1 or 2, wherein the first resin layer has a thickness of 5 to 15 µm.   The prepreg according to any one of claims 1 to 3, wherein the first resin composition contains a curable resin.   The prepreg according to claim 4, wherein the curable resin contains a cyanate resin.   The prepreg according to claim 5, wherein the cyanate resin includes a novolac-type cyanate resin.   The prepreg according to any one of claims 1 to 6, wherein the first resin composition further contains a curing agent.   The prepreg according to claim 7, wherein the curing agent contains an imidazole compound.   The prepreg according to any one of claims 1 to 8, wherein the first resin composition further includes a second resin of a different type from the curable resin.   The prepreg according to claim 9, wherein the second resin contains a phenoxy resin.   The prepreg according to any one of claims 1 to 10, wherein a thickness of the first resin layer is thinner than a thickness of the second resin layer.   A substrate obtained by laminating the prepreg according to claim 1.   A semiconductor device comprising the substrate according to claim 12.

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