JP5552969B2 - Prepreg, substrate and semiconductor device - Google Patents

Description

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

  In recent years, in order to reduce the size and thickness of electronic components and electronic devices, it has been required to reduce the size and thickness of circuit boards used therefor. In order to meet this requirement, a circuit board having a multilayer structure is used and each layer is thinned.

  A circuit board having a multilayer structure is manufactured using, for example, two prepregs (a first prepreg and a second prepreg). In general, in order to thin the circuit board having such a configuration, a wiring portion is formed on one surface of the first prepreg, and the wiring portion is laminated on the first prepreg. Embedding on the other side is performed.

  In this case, high adhesion for forming the wiring portion is required on one surface side of the first prepreg, and high embedding property for embedding the wiring portion is required on the other surface side of the second prepreg. Is done. As a prepreg having such characteristics, for example, Patent Document 1 discloses a prepreg in which two resin layers made of different resin compositions are formed on both sides of a fiber base material.

  At present, such prepregs are improved for the purpose of further improving mechanical strength and durability.

International Publication No. 2007/063960 Pamphlet

  An object of the present invention is to provide a prepreg that can impart different uses, functions, performances, characteristics, etc. to both sides of the prepreg, and has excellent mechanical strength and durability, a substrate including the prepreg, and such a substrate. An object of the present invention is to provide a semiconductor device manufactured using the same.

Such an object is achieved by the present inventions (1) to (9) below.
(1) a flat fiber substrate;
A first resin layer located on one side of the fiber substrate and composed of a first resin composition;
A second resin layer that is located on the other surface side of the fiber base material and is composed of a second resin composition having a composition different from that of the first resin composition;
The first resin layer has a first impregnation portion impregnated with the first resin composition in a part of the fiber base in the thickness direction;
The second resin layer is more flexible than the first resin layer, and the second resin layer is not impregnated with the first resin composition , and the second resin layer is not impregnated with the second resin layer. A second impregnation portion impregnated with the resin composition;
In the fiber substrate, the first impregnation part and the second impregnation part are in contact with each other,
When the average thickness of the first impregnated portion is t _a1 [μm] and the average thickness of the second impregnated portion is t _b1 [μm], the relationship t _a1 > t _b1 is satisfied. Characteristic prepreg.

  (2) The prepreg according to (1) above, wherein an interface between the first impregnation part and the second impregnation part is uneven.

(3) The second resin layer is higher in flexibility than the first resin layer,
The average thickness of the portion of the first resin layer excluding the first impregnation portion is t _a2 [μm], and the average thickness of the portion of the second resin layer excluding the second impregnation portion is t The prepreg according to the above (1) or (2) , which satisfies a relationship of 1.2 × t _a2 <t _b2 when _b2 [μm].

(4) the first resin composition and the second resin composition, respectively, comprising a curable resin, the kind of the curable resin, the content, at least one of the molecular weight but different from the (1) thru | or the prepreg in any one of (3) .

(5) the fiber base material, prepreg according to any one of Ru (1) to a glass fiber substrate der (4).

(6) A substrate comprising a laminate formed by laminating a plurality of the prepregs according to any one of (1) to (5 ) above .

(7) The substrate according to (6) , further including a fiber base material between the adjacent prepregs.

(8) The substrate according to (6) or (7) , further including a metal layer on at least one surface of the laminate.

(9) The substrate according to any one of (6) to (8 ) above ,
A semiconductor device comprising: a semiconductor element mounted on the substrate.

  According to this invention, since the 1st resin composition which comprises the 1st resin layer, and the 2nd resin composition which comprises the 2nd resin layer are mutually different compositions, both surfaces of a prepreg In this case, a first resin layer and a second resin layer having different uses, functions, performances, and characteristics are formed.

  Moreover, according to this invention, a fiber base material can be protected by the 1st resin layer and the 2nd resin layer. Thereby, for example, even when an external impact is applied to the prepreg, the fiber base material itself is prevented from being destroyed, and thus the effect of improving the mechanical strength of the prepreg by the fiber base material is reliably exhibited.

  Moreover, since the 1st impregnation part of a 1st resin layer and the 2nd impregnation part of a 2nd resin layer closely_contact | adhere, it can prevent more reliably that each resin layer peels from a fiber base material, respectively. Can do. Thereby, the durability of the prepreg can be improved.

  Moreover, a board | substrate provided with the prepreg of the above structures is obtained, and also the semiconductor device manufactured using the said board | substrate is obtained.

It is sectional drawing which shows embodiment of the prepreg of this invention. It is sectional drawing which shows embodiment of the board | substrate of this invention. It is sectional drawing which shows embodiment of the semiconductor device of this invention.

  Hereinafter, preferred embodiments of a prepreg, a substrate, and a semiconductor device of the present invention will be described with reference to the accompanying drawings.

  1 is a cross-sectional view showing an embodiment of a prepreg of the present invention, FIG. 2 is a cross-sectional view showing an embodiment of a substrate of the present invention, and FIG. 3 is a cross-sectional view showing an embodiment of a semiconductor device of the present invention. .

<Prepreg>
First, the prepreg of the present invention will be described.

  In the following description, the upper side in FIG. 1 (the same applies to the following drawings) is described as “upper”, and the lower side is described as “lower”. Further, FIG. 1 (same in the following drawings) is greatly exaggerated in the thickness direction (vertical direction in the drawing).

A prepreg 1 shown in FIG. 1 includes a flat fiber substrate 2, a first resin layer 3 positioned on one surface (upper surface) side of the fiber substrate 2, and the other surface (lower surface) of the fiber substrate 2. ) Side second resin layer 4.
The fiber base material 2 has a function of improving the mechanical strength of the prepreg 1.

  Examples of the fiber substrate 2 include glass fiber substrates such as glass woven fabric and glass nonwoven fabric, polyamide resin fibers, aromatic polyamide resin fibers, polyamide resin fibers such as wholly aromatic polyamide resin fibers, polyester resin fibers, Synthetic fiber substrate, kraft paper, cotton linter composed of woven or non-woven fabric mainly composed of aromatic polyester resin fiber, polyester resin fiber such as wholly aromatic polyester resin fiber, polyimide resin fiber, fluororesin fiber, etc. Examples thereof include fiber base materials such as organic fiber base materials such as paper fiber base materials mainly composed of paper, mixed paper of linter and kraft pulp, and the like.

  Among these, it is preferable that the fiber base material 2 is a glass fiber base material. By using such a glass fiber substrate, the mechanical strength of the prepreg 1 can be further improved. In addition, there is an effect that the thermal expansion coefficient of the prepreg 1 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, it is preferable that glass is S glass or T glass. Thereby, the thermal expansion coefficient of a glass fiber base material can be made comparatively small, and for this reason, the prepreg 1 can be made as small as possible in the thermal expansion coefficient.

  Although the average thickness of the fiber base material 2 is not specifically limited, It is preferable that it is 150 micrometers or less, It is more preferable that it is 100 micrometers or less, It is further more preferable that it is about 10-50 micrometers. By using the fiber substrate 2 having such a thickness, the mechanical strength of the prepreg 1 can be ensured and the thickness thereof can be reduced. Furthermore, workability when performing processing such as drilling on the prepreg 1 can be improved. Moreover, in the state which made the prepreg 1 the board | substrate 10, the workability at the time of processing the through-hole (through hole) by mechanical drill or laser irradiation with respect to the said board | substrate 10 can also be improved. Furthermore, it is possible to improve the insulation reliability at a narrow pitch where the distance between pitches between the through holes is 70 μm or less.

  A first resin layer 3 is provided on one surface side of the fiber base 2, and a second resin layer 4 is provided on the other surface side. The first resin layer 3 is composed of a first resin composition, while the second resin layer 4 is composed of a second resin composition having a composition different from that of the first resin composition. ing.

  With this configuration, the composition of the resin composition can be appropriately set according to the characteristics required for each resin layer.

  In this embodiment, in order to form a wiring part (conductor pattern) on the 1st resin layer 3, the 1st resin composition is set to the composition which is excellent in adhesiveness with a metal. Moreover, in order to embed the wiring part of another prepreg 1 or another fiber base material in the second resin layer 4 reliably, the second resin layer 4 is composed of the first resin layer 3. The composition is set such that the flexibility (softness) is higher. Each such resin composition will be described in detail later.

  As shown in FIG. 1, in the present invention, a part of the fiber base 2 in the thickness direction is impregnated with the first resin composition (hereinafter, this part is referred to as “first impregnation part 31”), and the fiber The remaining portion of the substrate 2 that is not impregnated with the first resin composition is impregnated with the second resin composition (hereinafter, this portion is referred to as “second impregnation portion 41”). Thereby, the first impregnation part 31 which is a part of the first resin layer 3 and the second impregnation part 41 which is a part of the second resin layer 4 are located in the fiber base material 2. And in the fiber base material 2, the 1st impregnation part 31 (lower surface of the 1st resin layer 3) and the 2nd impregnation part 41 (upper surface of the 2nd resin layer 4) are contacting. In other words, in the present invention, the first resin composition is impregnated into the fiber base material 2 from the upper surface side of the fiber base material 2, and the second resin composition is from the lower surface side of the fiber base material 2, The fiber base material 2 is impregnated, and the voids in the fiber base material 2 are filled with these resin compositions.

  With this configuration, the fiber base 2 can be protected by the first resin layer 3 and the second resin layer 4. As a result, even when an external impact is applied to the prepreg 1, the fiber base material 2 itself can be prevented from being destroyed, and the effect of improving the mechanical strength of the prepreg 1 by the fiber base material 2 is ensured. It can be demonstrated.

  Further, when the interface 20 between the first impregnation portion 31 and the second impregnation portion 41 inside the fiber base 2 is viewed microscopically, it is preferable that the interface 20 is uneven (see FIG. 1). See enlarged detail view). Further, the interface 20 may be such that the first impregnation portion 31 (first resin layer 3) and the second resin layer 4 are melted and mixed with each other. Thereby, not only the anchor effect with respect to the fiber base material 2 of each resin layer but the adhesiveness of resin layers increases, and it can prevent more reliably that each resin layer peels from the fiber base material 2. FIG. Thereby, the durability of the prepreg 1 can be improved. Furthermore, when the prepreg 1 is used as the substrate 10, it is possible to improve the moisture absorption heat resistance.

  For example, first, the first resin layer 3 is formed once by supplying and impregnating the varnish of the first resin composition to one surface side of the fiber base 2. Thereafter, the second resin composition varnish is supplied and impregnated on the other surface side of the fiber substrate 2 to form the second resin layer 4, so that it can be reliably obtained. The degree of impregnation of each resin composition, that is, the thickness of each impregnation part can be set to a desired size by appropriately adjusting the impregnation temperature and the impregnation time, for example. Needless to say, the order of forming these resin layers may be reversed. Further, by forming at least one of the first resin layer 3 or the second resin layer 4 appropriately with a minute inorganic filler or a solvent, formation of irregularities of the interface 20 or the first impregnation is performed. The part 31 and the second resin layer 4 can be melted and mixed.

  Moreover, when supplying the varnish of the resin layer formed previously to the fiber base material 2, you may make it perform suction operation from the surface on the opposite side to supplying a varnish. Thereby, the resin composition which comprises the said resin layer impregnates the fiber base material 2 reliably, and the interface 20 formed in the fiber base material 2 is roughened, ie, the unevenness | corrugation was formed (rough surface) Thing). The degree of impregnation of the resin composition can be set to a desired size by appropriately adjusting the suction time and suction force, for example. Moreover, you may make it supply a varnish, giving the fiber base material 2 a vibration.

As described above, the flexibility of the second resin layer 4 is higher than that of the first resin layer 3. In such a magnitude relationship, the average thickness t _a1 [μm] of the first impregnation portion 31 is larger than the average thickness t _b1 [μm] of the second impregnation portion 41 (t _a1 > t _b1 ) It is preferable to set. This is due to the following reason.

When the flexibility of the second resin layer 4 is set higher than that of the first resin layer 3, the thermal expansion coefficient of the second resin layer 4 tends to be larger than that of the first resin layer 3. Therefore, when the opposite of magnitude relation between _{"t a1> t b1", "t} a1 _{<t b1",} when the prepreg 1 is heated, the inside of the fiber substrate 2, a second impregnation portion 41 However, there is a possibility that the fiber substrate 2 is deformed to a greater extent than the first impregnated portion 31 and a crack (crack) or the like occurs in the fiber base material 2 portion. The crack or the like in the fiber base material 2 part greatly affects the entire prepreg 1 and the prepreg 1 may not be able to withstand use.

On the other hand, if “t _a1 > t _b1 ”, it is possible to eliminate the above inconvenience, that is, to prevent or suppress the occurrence of cracks or the like in the prepreg 1. Thereby, the prepreg 1 can endure use.

Specifically, when the maximum thickness of the fiber substrate 2 is T [μm], the average thickness t _a1 is preferably 0.50 × T to 0.95 × T, and 0.7 It is more preferable that it is * T-0.9 * T. By setting the average thickness _ta1 in such a range, it is possible to more reliably prevent or suppress warping of the prepreg 1 while reliably preventing each resin layer from peeling from the fiber base 2. Can do.

Further, the average thickness of the portion (the first non-impregnated portion 32) excluding the first impregnation portion 31 of the first resin layer 3 is set to _ta2 [μm], and the second impregnation of the second resin layer 4 is performed. When the average thickness of the portion excluding the portion 41 (second non-impregnated portion 42) is t _b2 [μm], it is preferable that the relationship 1.2 × t _a2 <t _b2 is satisfied and 2 × t _a2 It is more preferable to satisfy the relationship <t _{b2, and} it is even more preferable to satisfy the relationship 3 × t _a <t _b . By satisfying such a relationship, a relatively high rigidity can be imparted to the portion on the upper surface side of the prepreg 1, so that the wiring portion is highly workable on the upper surface of the prepreg 1 (on the first non-impregnated portion 32). Can be formed. On the other hand, since the second resin layer 4 can have high flexibility and sufficient thickness, the second resin layer 4 (second non-impregnated portion 42) is connected to the wiring portion of another prepreg 1. When embedding other fiber base materials, the embedding can be reliably performed, that is, the embedding property to the wiring part of other prepregs 1 or other fiber base materials is improved.

Specifically, the average thickness t _a2 is preferably 0.1 to 15 μm, and more preferably 1 to 10 μm. On the other hand, the average thickness t _b2 is preferably 4 to 50 μm, and more preferably 8 to 40 μm.

  Now, in order to obtain the 1st resin layer 3 and the 2nd resin layer 4 which have said characteristic, respectively, the 1st resin composition and the 2nd resin composition are set as the following compositions. preferable.

  The first resin composition includes, for example, a curable resin, and includes at least one of a curing aid (for example, a curing agent and a curing accelerator) and an inorganic filler as necessary. .

  In order to improve the adhesion with the metal constituting the wiring part, a method of using a curable resin excellent in adhesion with the metal, a curing aid for improving the adhesion with the metal (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 such curable resins include urea (urea) resins, melamine resins, bismaleimide resins, polyurethane resins, resins having a benzoxazine ring, cyanate ester resins, bisphenol S-type epoxy resins, bisphenol F-type epoxy resins, and bisphenol S. A thermosetting resin such as an epoxy resin copolymerized with bisphenol F is preferably used. Among these, it is particularly preferable to use a cyanate resin (including a prepolymer of cyanate resin) as the curable resin.

  By using a thermosetting resin (particularly a cyanate resin), the coefficient of thermal expansion of the prepreg 1 can be reduced (hereinafter also referred to as “low thermal expansion”). Furthermore, the electrical characteristics (low dielectric constant, low dielectric loss tangent) of the prepreg 1 can be improved.

  Such a cyanate resin can be obtained, for example, by reacting a halogenated cyanide compound with a phenol and prepolymerizing it by a method such as heating, if necessary.

  Specific examples of the cyanate resin include novolac type cyanate resin, bisphenol A type cyanate resin, bisphenol E type cyanate resin, and bisphenol type cyanate resin such as tetramethylbisphenol F type cyanate resin. Among these, it is preferable that cyanate resin is a novolak-type cyanate resin.

  If a novolac-type cyanate resin is used, the cross-link density increases in the first resin layer 3 after curing after the substrate 10 (see FIG. 2) to be described later is manufactured, so the first resin layer 3 after curing. The heat resistance and flame retardance of the (obtained substrate) can be improved.

  Here, it is considered that the improvement in heat resistance is caused by the novolak cyanate resin forming a triazine ring after the curing reaction. Further, the flame retardancy is improved because the novolak-type cyanate resin has a high proportion of benzene rings due to its structure, so that the benzene rings are easily carbonized (graphitized), and the first resin layer 3 after curing has a carbonized portion. This is thought to be caused by the occurrence of

Furthermore, if a novolac-type cyanate resin is used, even if the prepreg 1 is thinned (for example, 35 μm or less in thickness), excellent rigidity can be imparted to the prepreg 1. Moreover, since the cured product is excellent in rigidity at the time of heating, the obtained substrate 10 is also excellent in reliability when the semiconductor element 500 (see FIG. 3) is mounted.
Specifically, a novolac type cyanate resin represented by the formula (I) can be used.

  In the novolak-type cyanate resin represented by the formula (I), the average number of repeating units “n” is not particularly limited, but is preferably 1 to 10, and more preferably 2 to 7. When the average number of repeating units “n” is less than the lower limit, the novolac cyanate resin is easily crystallized, and thus the solubility in a general-purpose solvent decreases. For this reason, depending on the content of the novolac-type cyanate resin, the varnish of the first resin composition may be difficult to handle. In addition, when the prepreg 1 is produced, tackiness occurs, and when the prepregs 1 come into contact with each other, a phenomenon (transfer) occurs in which the prepregs 1 adhere to each other or the first resin composition of one prepreg 1 moves to the other prepreg 1. May occur. On the other hand, if the average number of repeating units “n” exceeds the upper limit, the viscosity of the varnish of the first resin composition becomes too high, and the efficiency (the moldability of the first resin layer 3) when producing the prepreg 1 is increased. ) May decrease.

  Moreover, when using together the hardening | curing agent or hardening accelerator which improves the adhesiveness with the metal mentioned later, novolaks, such as a phenol novolak resin, a cresol novolak resin, a bisphenol A novolak resin other than the above-mentioned curable resin, for example. Type phenolic resin, unmodified resol phenolic resin, phenolic resin such as oil-modified resol phenolic resin modified with tung oil, linseed oil, walnut oil, etc., bisphenol such as bisphenol A epoxy resin, bisphenol F epoxy resin Other epoxy resins such as epoxy resin such as epoxy resin, novolak epoxy resin, novolac epoxy resin such as cresol novolak epoxy resin, epoxy resin such as biphenyl epoxy resin, unsaturated polyester resin, diallyl phthalate resin, silicone resin It can also be used RESIN.

  In addition to the thermosetting resin, for example, an ultraviolet curable resin, an anaerobic curable resin, or the like can be used as the curable resin.

  Although content of curable resin is not specifically limited, It is preferable that it is 5 to 50 weight% of the whole 1st resin composition, and it is more preferable that it is 10 to 40 weight%. When the content of the curable resin is less than the lower limit, depending on the type of the curable resin, the viscosity of the varnish of the first resin composition becomes too low and it is difficult to form the prepreg 1. There is. On the other hand, when the content of the curable resin exceeds the upper limit, the amount of other components is too small, and the mechanical strength of the prepreg 1 may be reduced depending on the type of the curable resin.

  Examples of the above-described curing aid (for example, a curing agent, a curing accelerator, etc.) include tertiary amines such as triethylamine, tributylamine, diazabicyclo [2,2,2] octane, 2-ethyl-4-ethylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2,4-diamino-6- [2'-methyl Imidazolyl- (1 ′)]-ethyl-s-triazine, 2,4-diamino-6- (2′-undecylimidazolyl) -ethyl-s-triazine, 2,4-diamino-6- [2′-ethyl Imidazole compounds such as -4-methylimidazolyl- (1 ′)]-ethyl-s-triazine and 1-benzyl-2-phenylimidazole It is below.

  Among these, the curing aid is preferably 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. 2-phenyl-4,5-dihydroxymethylimidazole is more preferable.

  Examples of the first resin composition include organic metals such as zinc naphthenate, cobalt naphthenate, tin octylate, cobalt octylate, bisacetylacetonate cobalt (II), and trisacetylacetonate cobalt (III). A salt, a phenol compound such as phenol, bisphenol A, and nonylphenol, an organic acid such as acetic acid, benzoic acid, salicylic acid, and paratoluenesulfonic acid can be used in combination.

  When using a curing aid, its content is preferably 0.01 to 3% by weight, more preferably 0.1 to 1% by weight of the entire first resin composition.

  Moreover, it is preferable that a 1st resin composition contains an inorganic filler. Thereby, even if the prepreg 1 is made thin (for example, a thickness of 35 μm or less), the prepreg 1 having excellent mechanical strength can be obtained. Furthermore, the low thermal expansion of the prepreg 1 can be improved.

  Examples of the inorganic filler include talc, alumina, glass, silica such as fused silica, mica, aluminum hydroxide, magnesium hydroxide and the like. Further, depending on the purpose of use of the inorganic filler, a crushed or spherical one is appropriately selected. Among these, from the viewpoint of excellent low thermal expansibility, the inorganic filler is preferably silica, and more preferably fused silica (particularly spherical fused silica).

  The average particle size of the inorganic filler is preferably 0.01 to 5.0 μm, and more preferably 0.2 to 2.0 μm. In addition, this average particle diameter can be measured with a particle size distribution meter (“LA-500” manufactured by HORIBA), for example.

  In particular, as the inorganic filler, 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 (particularly 0.1 to 0.5 μm) is more preferable. . Thereby, the varnish of the 1st resin composition can be more reliably impregnated in the fiber base material 2, and the fiber base material 2 of the formed 1st resin layer 3 (1st impregnation part 31). Unevenness can be more reliably formed on the surface inside the.

  Moreover, in order to improve the adhesiveness of the 1st resin layer 3 and a wiring part, you may use an inorganic filler soluble in an acid as an inorganic filler. Thereby, when the wiring part (conductor layer) is formed on the first resin layer 3 by plating, the adhesion (plating adhesion) of the wiring part to the first resin layer 3 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 the adhesiveness of the 1st resin layer 3 and a wiring part, you may use together an inorganic filler and an organic filler. Examples of the organic filler include resin fillers such as liquid crystal polymer and polyimide.

  When the inorganic filler is used, the content thereof is not particularly limited, but is preferably 20 to 70% by weight, more preferably 30 to 60% by weight of the entire first resin composition.

  When a cyanate resin (particularly a novolak cyanate resin) is used as the curable resin, it is preferable to use an epoxy resin (substantially free of halogen atoms) in combination. Examples of the epoxy resin include phenol novolac type epoxy resin, bisphenol type epoxy resin, naphthalene type epoxy resin, arylalkylene type epoxy resin, and the like.

  Among these, the epoxy resin is preferably an aryl alkylene type epoxy resin. By using the aryl alkylene type epoxy resin, it is possible to improve the moisture absorption solder heat resistance (solder heat resistance after moisture absorption) and flame retardancy in the cured first resin layer 3 (obtained substrate).

  The aryl alkylene type epoxy resin refers to an epoxy resin having one or more aryl alkylene groups in the repeating unit, and examples thereof include a xylylene type epoxy resin and a biphenyl dimethylene type epoxy resin. Among these, the aryl alkylene type epoxy resin is preferably a biphenyl dimethylene type epoxy resin.

  Specifically, a biphenyl dimethylene type epoxy resin represented by the formula (II) can be used.

  The average number of repeating units “n” of the biphenyl dimethylene type epoxy resin represented by the formula (II) is not particularly limited, but is preferably 1 to 10, and more preferably 2 to 5. When the average number of repeating units “n” is less than the lower limit, the biphenyldimethylene type epoxy resin is easily crystallized, so that the solubility in a general-purpose solvent decreases. For this reason, the varnish of the first resin composition may be difficult to handle. On the other hand, if the average number of repeating units “n” exceeds the upper limit, depending on the solvent used, the viscosity of the varnish of the first resin composition may increase. In this case, the fiber base material 2 cannot be sufficiently impregnated with the first resin composition, and as a result, the molding failure of the prepreg 1 and the mechanical strength may be reduced.

  When the epoxy resin is used in combination, the content is not particularly limited, but it is preferably 1 to 55% by weight, more preferably 2 to 40% by weight based on the entire first resin composition.

  Furthermore, you may add to a 1st resin composition the component (a resin etc. are included) which improves adhesiveness with a metal. Examples of such components include phenoxy resins, polyvinyl alcohol resins, coupling agents, and the like.

  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, it is preferable to use a phenoxy resin having a biphenyl skeleton and a bisphenol S skeleton as the phenoxy resin. Accordingly, the glass transition temperature of the phenoxy resin can be increased due to the rigidity of the biphenyl skeleton, and the adhesion of the phenoxy resin to the metal can be improved due to the presence of the bisphenol S skeleton. As a result, the heat resistance of the first resin layer 3 can be improved, and the adhesion of the wiring part (metal) to the first resin layer 3 can be improved when a multilayer substrate is manufactured. .

  It is also preferable to use a phenoxy resin having a bisphenol A skeleton and a bisphenol F skeleton as the phenoxy resin. Thereby, the adhesiveness to the 1st resin layer 3 of a wiring part can be further improved at the time of manufacture of a multilayer substrate.

  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 more preferably 10,000 to 60,000.

  When the phenoxy resin is used, its content is not particularly limited, but it is preferably 1 to 40% by weight, more preferably 5 to 30% by weight based on the entire first resin composition.

  As the coupling agent, it is preferable to use at least one selected from, for example, an epoxy silane coupling agent, a titanate coupling agent, an aminosilane coupling agent, and a silicone oil type coupling agent.

  When using a coupling agent, the content is not particularly limited, but it is preferably 0.05 to 3 parts by weight, and 0.1 to 2 parts by weight with respect to 100 parts by weight of the inorganic filler. More preferred.

  Moreover, the 1st resin composition can contain additives, such as an antifoamer, a leveling agent, a pigment, antioxidant, as needed besides the component demonstrated above.

  The second resin composition is set to a composition different from the first resin composition, specifically, a composition in which the second resin layer 4 is more flexible than the first resin layer 3. Yes.

  The constituents of the second resin composition can be the same as those mentioned in the first resin composition, but the type and content of the resin and filler, the molecular weight of the resin (average repeat The composition of the second resin composition differs from that of the first resin composition by making at least one such as the number of units different. As a result, the second resin layer 4 has different characteristics from the first resin layer 3.

  The thermal expansion coefficient in the surface direction of the second resin layer 4, that is, the longitudinal direction (X direction) and the width direction (Y direction) of the prepreg 1 is not particularly limited, but is preferably 20 ppm or less, More preferably, it is 16 ppm. When the thermal expansion coefficient of the second resin layer 4 is within the above range, the prepreg 1 can have high connection reliability, and the obtained substrate is excellent in mounting reliability of semiconductor elements and the like. Become.

  Further, the thermal expansion coefficient in the plane direction of the entire prepreg 1 is not particularly limited, but is preferably 16 ppm or less, more preferably 12 ppm or less, and further preferably 5 to 10 ppm. When the thermal expansion coefficient of the prepreg 1 is within the above range, the crack resistance to repeated thermal shocks is improved in the obtained substrate.

  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 (TA Instruments).

<Board>
Next, the substrate of the present invention will be described with reference to FIG. A substrate 10 shown in FIG. 2 includes a laminate 11 and metal layers 12 provided on both surfaces of the laminate 11.

  The laminate 11 includes two prepregs 1 arranged with the second resin layers 4 facing each other, and a fiber base material 13 sandwiched between the second resin layers 4.

  As the fiber base material 13, the same fiber base material 2 as described above can be used. In the present embodiment, since the second resin layer 4 has the characteristics (flexibility) as described above, at least a part of the fiber base material 13 is reliably embedded in the second resin layer 4. (Buried).

  The metal layer 12 is a part that is processed into a wiring part, for example, by bonding a metal foil such as a copper foil or an aluminum foil to the laminate 11, or plating copper or aluminum on the surface of the laminate 11. It is formed. In the present embodiment, since the first resin layer 3 has the characteristics as described above, the metal layer 12 can be held with high adhesion and the metal layer 12 can be used as a wiring portion with high processing accuracy. It can be formed.

  The peel strength between the metal layer 12 and the first resin layer 3 is preferably 0.5 kN / m or more, and more preferably 0.6 kN / m or more. Thereby, the connection reliability in the semiconductor device 100 (refer FIG. 3) obtained by processing the metal layer 12 into a wiring part can be improved more.

  In such a substrate 10, two prepregs 1 each having a metal layer 12 formed on the first resin layer 3 are prepared, and the fiber base material 13 is sandwiched between these prepregs 1. Examples thereof include a method of laminating using a pressure laminator and a laminator heated and pressurized under vacuum. The vacuum press can be performed with a normal hot press machine or the like sandwiched between flat plates. For example, a vacuum press manufactured by Meiki Seisakusho Co., Ltd., a vacuum press manufactured by Kitagawa Seiki Co., Ltd., a vacuum press manufactured by Mikado Technos, etc. Further, as a laminator apparatus, a commercially available vacuum laminating machine such as a vacuum applicator manufactured by Nichigo Morton, a vacuum pressurizing laminator manufactured by Meiki Seisakusho, a vacuum roll type dry coater manufactured by Hitachi Techno Engineering, or the like It can be manufactured using a belt press or the like.

  The substrate 10 of the present invention may include a laminate in which the fiber base material 13 is omitted, and the two prepregs 1 are formed by directly joining the second resin layers 4 together. It may be omitted.

<Semiconductor device>
Next, the semiconductor device of the present invention will be described with reference to FIG. In FIG. 3, the fiber base materials 2 and 13 are omitted, and the first resin layer 3 and the second resin layer 4 are shown as an integral unit.

  The semiconductor device 100 shown in FIG. 3 connects the bump 501 to the multilayer substrate 200, the pad portion 300 provided on the upper surface of the multilayer substrate 200, the wiring portion 400 provided on the lower surface of the multilayer substrate 200, and the pad portion 300. Thus, the semiconductor element 500 mounted on the multilayer substrate 200 is provided. In addition, a wiring part, a pad part, a solder ball, and the like may be provided on the lower surface of the multilayer substrate 200.

  The multilayer substrate 200 includes a substrate 10 provided as a core substrate, three prepregs 1a, 1b, 1c provided on the upper side of the substrate 10, and three prepregs 1d, 1e provided on the lower side of the substrate 10. 1f. The fiber base material 2, the first resin layer 3, and the second resin layer 4 constituting the prepregs 1a to 1c, respectively, from the substrate 10, the fiber base material 2 constituting the prepregs 1d to 1f, the first The arrangement order of the resin layer 3 and the second resin layer 4 from the substrate 10 is the same. That is, the prepregs 1a to 1c and the prepregs 1d to 1f are inverted from each other.

  The multilayer substrate 200 includes a circuit unit 201a provided between the prepreg 1a and the prepreg 1b, a circuit unit 201b provided between the prepreg 1b and the prepreg 1c, and a prepreg 1d and the prepreg 1e. The circuit portion 201d is provided, and the circuit portion 201e is provided between the prepreg 1e and the prepreg 1f.

  Furthermore, the multilayer substrate 200 is provided through each of the prepregs 1a to 1f, and includes a conductor portion 202 that electrically connects adjacent circuit portions or between the circuit portion and the pad portion.

  Each metal layer 12 of the substrate 10 is processed into a predetermined pattern, and the processed metal layers 12 are electrically connected to each other by a conductor portion 203 provided through the substrate 10.

  In the semiconductor device 100 (multilayer substrate 200), four or more prepregs 1 may be provided on one side of the substrate 10. Furthermore, the semiconductor device 100 may include a prepreg other than the prepreg 1 of the present invention.

  As described above, the prepreg, the substrate, and the semiconductor device of the present invention have been described with respect to the illustrated embodiment. However, the present invention is not limited to this, and the respective parts constituting the prepreg, the substrate, and the semiconductor device have the same functions. It can be replaced with any configuration that can be exhibited. Moreover, arbitrary components may be added.

In the configuration shown in FIG. 1, the prepreg has a magnitude relationship between the average thickness t _a1 and the average thickness t _b1 that satisfies t _a1 > t _b1 , but the opposite magnitude relationship is “t _a1 <t _When “ _b1 ” is set, warping of the prepreg 1 can be prevented or suppressed.

In the configuration shown in FIG. 1, the prepreg has a magnitude relationship between the average thickness t _a2 and the average thickness t _b2 that is t _a2 <t _b2 , but is not limited thereto, and for example, t _a2 > t _{b2 Or} t _a2 = t _b2 .

DESCRIPTION OF SYMBOLS 1, 1a, 1b, 1c, 1d, 1f, 1f Prepreg 2 Fiber base material 3 1st resin layer 31 1st impregnation part 32 1st non-impregnation part 4 2nd resin layer 41 2nd impregnation part 42 Second non-impregnated portion 10 Substrate 11 Laminate 12 Metal layer 13 Fiber base material 20 Interface 100 Semiconductor device 200 Multilayer substrate 201a, 201b, 201d, 201e Circuit portion 202, 203 Conductor portion 300 Pad portion 400 Wiring portion 500 Semiconductor element 501 Bumps t _a1 , t _a2 , t _b1 , t _b2 average thickness T maximum thickness

Claims (9)

A flat fiber substrate;
A first resin layer located on one side of the fiber substrate and composed of a first resin composition;
A second resin layer that is located on the other surface side of the fiber base material and is composed of a second resin composition having a composition different from that of the first resin composition;
The first resin layer has a first impregnation portion impregnated with the first resin composition in a part of the fiber base in the thickness direction;
The second resin layer is more flexible than the first resin layer, and the second resin layer is not impregnated with the first resin composition , and the second resin layer is not impregnated with the second resin layer. A second impregnation portion impregnated with the resin composition;
In the fiber substrate, the first impregnation part and the second impregnation part are in contact with each other,
When the average thickness of the first impregnated portion is t _a1 [μm] and the average thickness of the second impregnated portion is t _b1 [μm], the relationship t _a1 > t _b1 is satisfied. Characteristic prepreg.   The prepreg according to claim 1, wherein an interface between the first impregnation part and the second impregnation part is uneven. The second resin layer is more flexible than the first resin layer,
The average thickness of the portion of the first resin layer excluding the first impregnation portion is t _a2 [μm], and the average thickness of the portion of the second resin layer excluding the second impregnation portion is t 3. The prepreg according to claim 1, wherein a relation of 1.2 × t _a2 <t _b2 is satisfied when _b2 [μm] is satisfied. The first resin composition and the second resin composition, respectively, comprising a curable resin, the kind of the curable resin, the content, to at least one of claims 1 to different ones of the molecular weight The prepreg according to any one of 3 above. The prepreg according to any one of claims 1 to 4 , wherein the fiber base material is a glass fiber base material. A substrate comprising a laminate formed by laminating a plurality of the prepregs according to claim 1 . The substrate according to claim 6 , further comprising a fiber base material between the adjacent prepregs. The substrate according to claim 6 or 7 , further comprising a metal layer on at least one surface of the laminate. A substrate according to any one of claims 6 to 8 ,
A semiconductor device comprising: a semiconductor element mounted on the substrate.

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