JP4821226B2 - Circuit board with built-in semiconductor element and semiconductor device - Google Patents

Description

The present invention relates to a circuit board with a built- in semiconductor element and a semiconductor device.

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

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

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

Examples of a method for obtaining such an insulating resin layer include a method of highly filling an inorganic filler in at least one resin composition selected from an epoxy resin, a phenol resin, and a cyanate resin (see, for example, Patent Document 1). .
However, high filling with inorganic fillers in epoxy resin, phenol resin and cyanate resin increases the dielectric constant, and the resin itself has a high water absorption rate. Therefore, signal propagation speed and connection after water absorption treatment, which are important in high frequency applications, are required. Reliability may be affected.

Therefore, there has been a demand for a substrate having a resin layer that can incorporate mounting components and the like.

JP-A-11-220262

An object of the present invention is to provide a semiconductor element built-in circuit board excellent in mechanical strength and dielectric characteristics, and a semiconductor device using the same.

Such an object is achieved by the present invention described in the following (1) to ( 6 ).
(1) A circuit board with a built-in semiconductor element, which includes a substrate and a resin layer, and a semiconductor element is provided in the resin layer, the resin layer comprising 10 to 30 % by weight of benzocyclobutene resin and inorganic filling Characterized in that it is composed of a resin composition containing 65 to 80 % by weight of a material, and an end-acrylated polybutadiene elastomer as an elastomer dissolved in MEK, and the linear expansion coefficient of the resin layer is 25 ppm / ° C. or less. A circuit board with a built-in semiconductor element.
(2) The circuit board with a built-in semiconductor element according to (1), wherein the resin layer is formed so as to seal the semiconductor element.
(3) The circuit board with a built-in semiconductor element according to (1) or (2), wherein the inorganic filler contains spherical silica.
(4) The semiconductor element built-in circuit board according to any one of (1) to (3), wherein an average particle diameter of the inorganic filler is 1.0 μm or more.
(5) The circuit board with a built-in semiconductor element according to any one of (1) to (4), wherein the resin layer has a thickness of 20 to 100 μm.
(6) A semiconductor device comprising the circuit board with a built-in semiconductor element according to any one of (1) to (5).

According to the present invention, a circuit board with a built-in semiconductor element excellent in mechanical strength and dielectric characteristics and a semiconductor device using the same can be obtained.
In addition, when an inorganic filler having an average particle diameter of 1.0 μm or more is used, the fluidity of the resin composition at the time of press molding is improved, so that it is more than that of an inorganic filler having an average particle diameter of 1.0 μm or less. Since many can be filled, it is possible to obtain a circuit board with a built-in semiconductor element having a resin layer excellent in crack resistance in a thermal cycle test.

The semiconductor element built-in circuit board and semiconductor device of the present invention will be described below.
The semiconductor device built-in circuit board of the present invention includes a substrate, formed of a resin layer, a semiconductor element built-in circuit board on which a semiconductor element is provided on the resin layer, the resin layer, benzocyclobutene resin 10 It is comprised with the resin composition containing 40 weight% and inorganic filler 60-90 weight%, and the linear expansion coefficient of this resin layer is 30 ppm / degrees C or less, It is characterized by the above-mentioned.
A semiconductor device according to the present invention includes the above-described circuit board with a built-in semiconductor element.

First, a circuit board with a built- in semiconductor element will be described.
The circuit board 100 with a built-in semiconductor element includes a core substrate 1, a first conductor portion 11 and a resin layer 2 formed on the upper side of the core substrate 1 (upper side in FIG. 1) so as to cover the first conductor portion 11. And are provided.
A semiconductor element 3 is provided inside the resin layer 2.
The semiconductor element 3 and the core substrate 1 are connected via an adhesive resin 31.
An electrode 32 is provided on the upper side of the semiconductor element 3 (upper side in FIG. 1). The conductor 21 provided on the upper side of the resin layer 2 and the electrode 32 include a via 22 provided on the resin layer 2. It is energized with the conductive paste embedded in.
A via 23 is formed so as to penetrate through the resin layer 2, and a conductive paste is embedded in the via 23.
A conductor 21 is formed on the upper side of the resin layer 2 (upper side in FIG. 1). The conductor 21 and the first conductor portion 11 are energized by a conductive paste provided inside the via 23.
A third conductor portion 12 is provided on the lower side of the core substrate 1 (lower side in FIG. 1), and the first conductor portion 11 and the second conductor portion 12 are provided through the core substrate 1. The conductive paste provided in the via 13 is energized.

The resin layer 2 is composed of a resin composition containing 10 to 40% by weight of a benzocyclobutene resin and 60 to 90% by weight of an inorganic filler. Thereby, the characteristic of the resin layer 2 requested | required of the circuit board 100 with a built- in semiconductor element can be satisfied.

(BCB resin)
The benzocyclobutene resin may be any resin as long as it contains a cyclobutene skeleton. Specifically, it is preferably a resin composed of a benzocyclobutene derivative represented by the following general formula (IA), (IB), or (IC) as a monomer.

（式中、Ｒ1は、ハロゲン原子、アルキル基、ハロアルキル基、アリール基、シクロアルキル基、ヒドロキシル基、アルコキシ基、カルボキシル基、アルコキシカルボニル基、アシル基を示す。式中、Ｒ２、Ｒ３、Ｒ４およびＲ５は、同一または異なり、水素原子、ハロゲン原子、アルキル基、ハロアルキル基、アリール基、シクロアルキル基、ヒドロキシル基、アルコキシ基、カルボキシル基、アルコキシカルボニル基、アシル基を示す。前記Ｒ２およびＲ３、または前記Ｒ４およびＲ５は、互いに結合して環を形成してもよい。）

(Wherein R1 represents a halogen atom, an alkyl group, a haloalkyl group, an aryl group, a cycloalkyl group, a hydroxyl group, an alkoxy group, a carboxyl group, an alkoxycarbonyl group, or an acyl group. In the formula, R2, R3, R4 and R5 is the same or different and represents a hydrogen atom, a halogen atom, an alkyl group, a haloalkyl group, an aryl group, a cycloalkyl group, a hydroxyl group, an alkoxy group, a carboxyl group, an alkoxycarbonyl group, an acyl group, R2 and R3, or R4 and R5 may be bonded to each other to form a ring.)

  In addition, a B-staged benzocyclobutene derivative represented by the above general formula is preferably used in order to adjust moldability and fluidity. As the B-staged benzocyclobutene derivative, for example, divinylsiloxane-bisbenzocyclobutene (B-staged. Weight average molecular weight 140,000, cycloten XUR manufactured by Dow Chemical Company) can be used. B-staging is usually performed by heating and melting. Here, the weight average molecular weight can be measured using, for example, gel permeation chromatography (GPC).

The weight average molecular weight of the benzocyclobutene resin is not particularly limited, but is preferably 100 or more, and particularly preferably 1,000 to 300,000. When the weight average molecular weight is less than the lower limit value, the benzocyclobutene resin may be insufficiently cured. When the weight average molecular weight exceeds the upper limit value, the resin composition becomes brittle after being B-staged and the workability is lowered. There is a case.
As a method of obtaining a low molecular weight benzocyclobutene resin, for example, a method of shortening the polymerization time of a benzocyclobutene monomer to lower the degree of polymerization of the benzocyclobutene resin, a benzocyclobutene monomer and a spacer such as a linear monomer And the like, and the like, and the like, and the like.

The content of the benzocyclobutene resin is 10 to 40% by weight of the entire resin composition. By setting the content of the benzocyclobutene resin within the above range, it is possible to improve the dielectric characteristics without impairing the tensile strength and the elastic modulus. Furthermore, it can be made into a low water absorption compared with the epoxy resin widely used with a laminated board.
More specifically, the content of the benzocyclobutene resin is preferably 15 to 35% by weight, and particularly preferably 20 to 30% by weight of the resin composition.

  The melt viscosity at 25 ° C. of the benzocyclobutene resin (concentration 50%, mesitylene solvent) is not particularly limited, but is preferably 0.5 to 30 (P), particularly 1 to 20 (P). Is preferred. When the melt viscosity is within the above range, good moldability can be obtained even when 60 to 90% by weight of the inorganic filler is added.

(Inorganic filler)
The resin composition includes an inorganic filler in an amount of 60 to 90% by weight based on the entire resin composition. Thereby, mechanical characteristics can be improved. In particular, excellent effect of preventing the occurrence of cracks during Oite thermal cycle when used with a small metal linear expansion coefficient of silicon or copper.
More specifically, the content of the inorganic filler is preferably 65 to 85% by weight, and particularly preferably 70 to 80% by weight of the resin composition.

Examples of the inorganic filler include silicates such as talc, calcined clay, unfired clay, mica and glass, oxides such as titanium oxide, alumina, silica and fused silica, calcium carbonate, magnesium carbonate, hydrotalcite and the like. Carbonates, hydroxides such as aluminum hydroxide, magnesium hydroxide, calcium hydroxide, sulfates or sulfites such as barium sulfate, calcium sulfate, calcium sulfite, zinc borate, barium metaborate, aluminum borate, boron Examples thereof include borates such as calcium oxide and sodium borate, and nitrides such as aluminum nitride, boron nitride, and silicon nitride.
Among these, silica (especially spherical silica) is preferable. Thereby, it is excellent in the balance between workability and mechanical properties.

  The average particle size of the inorganic filler is not particularly limited, but is preferably 1.0 μm or more, and particularly preferably 1.5 to 5.0 μm. When the average particle diameter is less than the lower limit value, fine cracks may occur when the resin layer 2 is subjected to a thermal cycle test, and when the upper limit value is exceeded, connection reliability may be reduced. Here, the average particle diameter of the inorganic filler can be measured by, for example, a particle size distribution meter (manufactured by HORIBA, LA-500). Furthermore, when a filler having an average particle diameter of 1.0 μm or more is used, the fluidity of the resin composition is increased, and handling properties and press moldability can be improved.

The relative dielectric constant of the inorganic filler is not particularly limited, but the relative dielectric constant is preferably 20 or less, more preferably 10 or less, and the relative dielectric constant is 1 to 8. Is more preferable. Thereby, when manufacturing the circuit board 100 with a built-in semiconductor element using the said resin composition, crack resistance can be improved, without reducing a dielectric characteristic. In addition, this makes it possible to cope with further increase in the signal propagation speed. Furthermore, the combination of the inorganic filler having a relative dielectric constant of 20 or less and the benzocyclobutene resin described above can improve the crack resistance without deteriorating the dielectric properties of the resin layer 2.

  Examples of the inorganic filler having a relative dielectric constant of 20 or less include oxides such as silica, alumina, magnesia or beryllia, and sulfates such as barium sulfate. Among these, at least one selected from silica, alumina, and barium sulfate is preferable. Thereby, the low dielectric constant and low dielectric loss tangent characteristics of the benzocyclobutene resin can be maintained.

(Elastomer-)
The resin composition is not particularly limited, but preferably contains an elastomer. Thereby, it is especially excellent in crack resistance at the time of a thermal cycle test.
Examples of the elastomer include polystyrene-based thermoplastic elastomers such as styrene-butadiene copolymer and styrene-isoprene copolymer, thermoplastic elastomers such as polyolefin-based thermoplastic elastomer, polyamide-based elastomer, and polyester-based elastomer, polybutadiene, and epoxy-modified. Examples thereof include liquid elastomers such as polybutadiene, acrylic-modified polybutadiene, and methacryl-modified polybutadiene. Among these, at least one selected from styrene-butadiene copolymer, epoxy-modified polybutadiene, acrylic-modified polybutadiene, and methacryl-modified polybutadiene is preferable. Thereby, it is possible to improve the adhesion with the metal without particularly deteriorating the dielectric properties of the benzocyclobutene resin.

  The content of the elastomer is not particularly limited, but is preferably 1 to 30% by weight, and particularly preferably 5 to 20% by weight, based on the entire resin composition. When the content is within the above range, the crack resistance particularly during the thermal cycle test is excellent.

(UV absorber)
Although the resin composition of this invention is not specifically limited, You may contain a ultraviolet absorber. Thereby, the laser workability of the semiconductor element built-in circuit board 100 finally obtained can be improved.
Therefore, the resin composition is preferably formed so as to have an ultraviolet absorption region at 200 to 400 nm. Thereby, a micro via hole can be formed by UV laser, and laser workability can be improved.

  In order to impart such an ultraviolet absorption region to the resin composition, the resin composition includes the ultraviolet absorber having an absorption rate of 40% or more in a wavelength region of 350 nm to 370 nm or 240 to 260 nm. Can do. As a result, productivity can be improved particularly when via processing is performed with a UV laser. Here, having an absorption rate of 40% or more in the wavelength region means that the absorption rate is 40% or more in all ranges even if the absorption rate is 40% or more in a part of the wavelength region. Also good. Here, the absorptance is obtained, for example, when a sample containing a solution containing 5 mg of an ultraviolet absorber in 100 ml of a methanol solvent in a cell having a sample optical path length of 1 cm is measured for ultraviolet region absorption with a photoelectric spectrophotometer. What is obtained by the shape of the wavelength obtained is shown.

  Examples of the ultraviolet absorber include benzophenones such as 4,4′-bisdiethylaminobenzophenone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2- (5- ( Benzotriazoles such as chloro-2'-hydroxy-3'tert-butyl-5'methylphenyl) -benzotriazole, 1,1 ', 2,2'-tetrakis (4-glycidylphenyl) ethane, 2,2 dimethoxy -1,2-diphenylethane-1-one, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropanone-1-benzoin isopropyl ether, benzoin isobutyl ether, benzyl dimethyl ketal, 2-benzyl- 2-Dimethylamino-1- (4-morpholinophenyl) -butanone-1, bis (2,4,6 trimethylbenzoyl) -phenylphosphine Among these, benzophenones or benzotriazoles are preferable, and benzophenones such as 4,4′-bisdiethylaminobenzophenone are more preferable, thereby improving the UV laser processability of the resin composition. In particular, it can be improved.

  Although content of the said ultraviolet absorber is not specifically limited, 0.01-5 weight part is preferable with respect to 100 weight part of benzocyclobutene resin, and 0.1-1.5 weight part is especially preferable. If the content is less than the lower limit, the effect of improving laser processability may be reduced, and if the content exceeds the upper limit, the effect of improving dielectric properties may be reduced. In addition, it can be evaluated by, for example, an ultraviolet spectrophotometer (Shimadzu Corporation UV-260) that the resin composition has an ultraviolet absorption region.

  The resin composition of the present invention includes the above-described benzocyclobutene resin and the like, but other resins, curing accelerators, coupling agents, flame retardants, fillers, and other components are included within the scope not departing from the object of the present invention. Can be added.

As a method for obtaining the resin layer 2 from such a resin composition, for example, the resin composition can be obtained by dissolving the resin composition in a solvent and applying it by a casting method, a spin coating method, or a spray method.
Although it does not specifically limit as thickness of the resin layer 2, 20-100 micrometers is preferable and 30-80 micrometers is especially preferable.

The thermal expansion coefficient of the resin layer 2 is 30 ppm / ° C. or less. Thereby, thermal shock reliability can be improved. The thermal expansion coefficient of the conventional resin layer was about 50 ppm / ° C. Such a thermal expansion coefficient has a problem that the thermal shock reliability is insufficient.
On the other hand, in the present invention, since the thermal expansion coefficient of the resin layer is set to 30 ppm / ° C. or less, the thermal shock reliability can be improved. Specifically, the thermal expansion coefficient is preferably 25 ppm / ° C. or less, and particularly preferably 20 ppm / ° C. or less.
In the present invention, the thermal expansion coefficient of the resin layer 2 can be reduced to 30 ppm / ° C. or less by using the benzocyclobutene resin and the inorganic filler together in a predetermined ratio, whereby the resin layer 2 can be provided with a semiconductor element.

Next, a method for manufacturing the semiconductor element built-in circuit board 100 will be described.
A through-hole 13 is formed at a predetermined position of the core substrate 1 and a conductive paste is embedded. And the 1st conductor part 11 and the 2nd conductor part 12 are formed in the upper and lower sides (upper and lower in FIG. 1) of the core board | substrate 1 by a subtractive and additive method, for example. The first conductor portion 11 and the second conductor portion 12 are electrically connected by a conductive paste embedded in the through hole 13.
Examples of the core substrate 1 include a glass cloth-containing resin substrate and a ceramic substrate. The core substrate 1 may be a metal substrate such as an aluminum substrate. In this case, it is not necessary to provide the first conductor portion 11, the second conductor portion 12, and the like.

  Next, the semiconductor element 5 is installed on a predetermined part of the core substrate 1 via the adhesive resin 31. And the electrode 32 is provided in the upper side (upper side in FIG. 1) of the semiconductor element 5, and the resin layer 2 is formed so that these may be covered.

After the vias 22 and 23 are formed in predetermined portions of the resin layer 2, a conductive paste is embedded. Then, the conductor 21 is formed by, for example, a subtractive or additive method, and the second conductor portion 21, the first conductor portion 11, the electrode 32, and the second conductor provided on the upper side of the resin layer 2 (upper side in FIG. 1). The circuit board 100 with a built-in semiconductor element is obtained by electrically connecting the part 21.

  As what constitutes the adhesive resin 31, for example, an epoxy resin, a polyimide resin, a cyanate ester resin, a maleimide resin, a benzocyclobutene resin or the like alone or in the resin material, gold, silver, copper, nickel, silica, alumina, Examples include those added with at least one filler selected from boron nitride and the like.

The thickness of the adhesive resin 31 is not particularly limited, but is preferably 0.1 to 20 μm, and particularly preferably 0.2 to 10 μm. Heat dissipation can be improved as thickness is in the said range.
As such a semiconductor element 5, semiconductor elements, such as Si and GaAs, are mentioned, for example.
In FIG. 1, one resin layer 2 is described. However, the present invention is not limited to this, and a multilayer substrate such as two layers or three layers may be used. In FIG. 1, the semiconductor element 3 is provided on one side of the core substrate 1, but a structure may be provided on both sides.

Next, although this invention is demonstrated in detail based on an Example and a comparative example, this invention is not limited to this.
Example 1
1. Preparation of varnish for forming resin layer Divinylsiloxane-bisbenzocyclobutene (B-staged, number average molecular weight 140,000, cycloten manufactured by Dow Chemical Co., Ltd.) as a benzocyclobutene resin with respect to the entire solid content of the resin composition XUR) 22% by weight, terminal acrylated polybutadiene elastomer (number average molecular weight 2,800, BAC-45 manufactured by Osaka Organic Chemical Industry Co., Ltd.) 2.5% by weight as an elastomer, and 4,4′-bisdiethylamino as an ultraviolet absorber 0.1% by weight of benzophenone, 0.2% by weight of γ-methacryloxypropyltrimethoxysilane (SZ6030 manufactured by Toray Dow Corning Silicone) as a surface treatment agent, and 2,6-di- (paraazide) as a curing agent Benzal) -4-ethylcyclohexanone 0.2% by weight is dissolved in MEK. Silica as the inorganic filler (Admatechs Co. SE5050, average particle size 1.5 [mu] m, maximum particle size 5 [mu] m) was added to 75 wt% is dispersed, the resin varnish was prepared so that the nonvolatile content of 50 wt%.

2. Production of resin layer with carrier film Using the above-mentioned resin varnish, a resin varnish was applied to a carrier film (thickness 0.038 mm, PET) with a thickness of 0.14 mm, and then in an oven at 80 ° C. for 5 minutes. It dried for 5 minutes with a 140 degreeC drying furnace, and produced the resin layer with a carrier film whose thickness of a resin layer is 0.07 mm. The expansion coefficient of the obtained resin layer was 20 ppm / ° C.

3. Manufacture of multilayer printed circuit board After reducing the copper foil surface of the double-sided copper-clad laminate with copper foil on both sides to black core (copper oxide formation) and then reducing the core substrate, the semiconductor element is bonded to one side, The above-mentioned resin layer with a carrier film is applied to both surfaces of the core substrate at 170 ° C. for 1 hour, and then the carrier film is peeled off, followed by heating and pressure bonding at 200 ° C. for 2 hours. A substrate was manufactured.

(Example 2)
Example 1 was performed except that the following inorganic fillers were used.
Silica (“SE2050” manufactured by Admatechs, average particle size of 0.5 μm, maximum particle size of 5 μm) was used as the inorganic filler. The expansion coefficient of the obtained resin layer was 20 ppm / ° C.

( Comparative Example 4 )
The procedure was the same as Example 1 except that the blending of the benzocyclobutene resin and the inorganic filler in the resin varnish was as follows.
11.7% by weight of divinylsiloxane-bisbenzocyclobutene (B-staged, number average molecular weight 140,000, cycloten XUR manufactured by Dow Chemical Co.) as a benzocyclobutene resin, based on the total solid content of the resin composition 2.9% by weight of terminal acrylated polybutadiene elastomer (number average molecular weight 2,800, BAC-45 manufactured by Osaka Organic Chemical Industry Co., Ltd.) as an elastomer, and 2,6-di- (paraazidobenzal) -4-ethyl as a curing agent Cyclohexanone was 0.1% by weight, and silica as an inorganic filler (SE5050 manufactured by Admatechs, average particle size of 1.5 μm, maximum particle size of 5 μm) was 85% by weight. In addition, the expansion coefficient of the obtained resin layer was 15 ppm / ° C.

( Comparative Example 5 )
The procedure was the same as Example 1 except that the blending of the benzocyclobutene resin and the inorganic filler in the resin varnish was as follows.
Divinylsiloxane-bisbenzocyclobutene (B-staged, number average molecular weight 140,000, cycloten XUR manufactured by Dow Chemical Co.) as a benzocyclobutene resin, 35.3% by weight based on the total solid content of the resin composition Terminal acrylated polybutadiene elastomer (number average molecular weight 2,800, BAC-45 manufactured by Osaka Organic Chemical Industry Co., Ltd.) 4.1% by weight as an elastomer, and 2,6-di- (paraazidobenzal) -4- Ethylcyclohexanone was 0.3% by weight, and the inorganic filler was 60% by weight of silica (SE5050 manufactured by Admatechs, average particle size 1.5 μm, maximum particle size 5 μm). In addition, the expansion coefficient of the obtained resin layer was 28 ppm / ° C.

(Example 5)
The same procedure as in Example 1 was carried out except that the elastomer varnish was not used and the resin varnish was blended as follows. The obtained resin layer had an expansion coefficient of 19 ppm / ° C.
Divinylsiloxane-bisbenzocyclobutene (B-staged, number average molecular weight 140,000, cycloten XUR manufactured by Dow Chemical Co.) 24.5% by weight as the benzocyclobutene resin based on the total solid content of the resin composition , 0.1% by weight of 4,4′-bisdiethylaminobenzophenone as an ultraviolet absorber, 0.2% by weight of γ-methacryloxypropyltrimethoxysilane (SZ6030 manufactured by Toray Dow Corning Silicone) as a surface treatment agent, curing agent 2,6-di- (paraazidobenzal) -4-ethylcyclohexanone 0.2% by weight is dissolved in mesitylene, and silica (SE5050 manufactured by Admatechs, average particle size 1.5 μm, (Maximum particle size 5 μm) Add 75% by weight to disperse, so that the non-volatile concentration is 50% by weight The resin varnish was prepared.

(Comparative Example 1)
The same procedure as in Example 1 was performed except that an epoxy resin was used as follows instead of the benzocyclobutene resin. The expansion coefficient of the obtained resin layer was 20 ppm / ° C.
NC-3000 (manufactured by Nippon Kayaku Co., Ltd.) 22% by weight as the epoxy resin, and terminal acrylated polybutadiene elastomer (number average molecular weight 2,800, BAC-manufactured by Osaka Organic Chemical Industries, Ltd.) 45) 2.5% by weight, 4,4′-bisdiethylaminobenzophenone as an ultraviolet absorber, 0.1% by weight, and γ-methacryloxypropyltrimethoxysilane (SZ6030, manufactured by Toray Dow Corning Silicone) as a surface treatment agent 0 0.2% by weight, 2-phenyl-4-methylimidazole (2P4MZ, manufactured by Shikoku Kasei Kogyo Co., Ltd.) as a curing agent, silica (SE5050, manufactured by Admatechs, average particle size 1.5 μm, maximum particle) as an inorganic filler The diameter was 5 μm) and 75 wt%.

(Comparative Example 2)
The same procedure as in Example 1 was performed except that the resin varnish was blended as follows without using an inorganic filler.
Divinylsiloxane-bisbenzocyclobutene (B-staged, number average molecular weight 140,000, cycloten XUR manufactured by Dow Chemical Co.) as a benzocyclobutene resin is 87.5% by weight based on the total solid content of the resin composition. 11.6% by weight of terminal acrylated polybutadiene elastomer (number average molecular weight 2,800, BAC-45 manufactured by Osaka Organic Chemical Co., Ltd.) as an elastomer and 0.1% by weight of 4,4′-bisdiethylaminobenzophenone as an ultraviolet absorber And 0.2% by weight of γ-methacryloxypropyltrimethoxysilane (SZ6030 manufactured by Toray Dow Corning Silicone Co., Ltd.) as a surface treating agent, and 2,6-di- (paraazidobenzal) -4- Dissolve 0.6% by weight of ethylcyclohexanone in MEK to a non-volatile content of 50% by weight. The resin varnish was prepared as. In addition, the expansion coefficient of the obtained resin layer was 80 ppm / ° C.

(Comparative Example 3)
The same procedure as in Example 1 was conducted except that the resin varnish was mixed as follows.
Divinylsiloxane-bisbenzocyclobutene (B-staged, number average molecular weight 140,000, cycloten XUR manufactured by Dow Chemical Co.) as a benzocyclobutene resin is 44.4% by weight based on the total solid content of the resin composition. 5% by weight of terminal acrylated polybutadiene elastomer (number average molecular weight 2,800, BAC-45 manufactured by Osaka Organic Chemical Industry Co., Ltd.) as an elastomer, 0.1% by weight of 4,4′-bisdiethylaminobenzophenone as a UV absorber, surface treatment agent Γ-methacryloxypropyltrimethoxysilane (SZ6030 manufactured by Toray Dow Corning Silicone Co., Ltd.) 0.2% by weight, 2,6-di- (paraazidobenzal) -4-ethylcyclohexanone 0.3% by weight as a curing agent %, Silica as an inorganic filler (SE5050 by Admatechs, flat Particle size 1.5 [mu] m, maximum particle size 5 [mu] m) was 50 wt%. In addition, the expansion coefficient of the obtained resin layer was 60 ppm / ° C.

The following evaluation was performed about the board | substrate obtained by each Example and each comparative example. However, the dielectric constant, dielectric loss tangent, mechanical strength, and linear expansion coefficient were evaluated by heating and pressure-bonding the above resin layer with a carrier film at 170 ° C. for 1 hour, followed by peeling the carrier film at 200 ° C. for 2 hours. went. The evaluation items are shown together with the contents. The obtained results are shown in Table 1.
1. Dielectric constant and dielectric loss tangent Measured according to JIS C 6481 under conditions of 1 MHz and A state.

2. Mechanical strength In accordance with JIS C 6481, the load full scale is 20 kgf and the speed is 5 mm / min. The elastic modulus and tensile strength were measured under the following conditions.

3. Linear expansion coefficient It measured in the temperature range of 35-85 degreeC with the temperature increase rate of 10 degree-C / min.

4). Cooling cycle test In the liquid phase cooling test, evaluation was performed based on the presence or absence of cracks after 1000 and 2000 cycles of treatment at -65 ° C and 125 ° C for 30 minutes each. For the evaluation, Tabai Espec liquid tank thermal shock device TSB-2 type, Fluorinert liquid was used. The presence or absence of cracks was judged with a microscope. Each symbol indicates the following items.
A: Cracks hardly occurred in both 1,000 and 2,000 cycles.
○: Almost no cracks occurred at 1,000 cycles, but some cracks occurred at 2,000 cycles.
(Triangle | delta): In either 1,000 and 2,000 cycles, a crack generate | occur | produced partially and it was unpractical.
X: Many cracks occurred in both 1000 cycles and 2000 cycles.

5). Moisture absorption reflow test After treatment for 40 hours in an environment of 60 ° C. and 60%, the circuit board with a built- in semiconductor element was treated three times at 260 ° C. for 5 minutes, and the presence or absence of swelling was judged with a microscope.
A: Almost no cracks occurred.
○: Some cracks occurred, but there was no practical problem.
(Triangle | delta): A crack generate | occur | produced partially and was unpractical.
X: Many cracks occurred.

As is apparent from Table 1, Examples 1 , 2 , and 5 have low dielectric constant and dielectric loss tangent, excellent tensile strength, etc., and excellent electrical and mechanical properties.
In Examples 1 , 2 , and 5 , cracks were hardly generated in the thermal cycle test, and the crack resistance was particularly excellent.
In Examples 1 , 2 , and 5 , cracks hardly occurred even in the moisture absorption reflow test, and the crack resistance after moisture absorption treatment was excellent.

The circuit board with a built- in semiconductor element and the semiconductor device using the same according to the present invention can cope with an increase in capacity, speed, density, etc. of communication equipment such as a mobile phone and a notebook personal computer.

It is sectional drawing which shows typically an example of the circuit board with a built- in semiconductor element of this invention.

DESCRIPTION OF SYMBOLS 1 Core substrate 11 1st conductor part 12 2nd conductor part 13 Through-hole 2 Resin layer 21 Conductor 22 Via 23 Via 3 Semiconductor element 31 Adhesive resin 32 Electrode 100 Circuit board with a built-in semiconductor element

Claims (6)

A circuit board with a built-in semiconductor element comprising a substrate and a resin layer, and a semiconductor element is provided in the resin layer,
The resin layer is composed of a resin composition containing 10 to 30 % by weight of a benzocyclobutene resin, 65 to 80 % by weight of an inorganic filler, and a terminal acrylated polybutadiene elastomer dissolved in MEK, and A circuit board with a built-in semiconductor element, wherein the linear expansion coefficient of the resin layer is 25 ppm / ° C. or less.   The circuit board with a built-in semiconductor element according to claim 1, wherein the resin layer is formed so as to seal the semiconductor element.   The circuit board with a built-in semiconductor element according to claim 1, wherein the inorganic filler contains spherical silica.   4. The circuit board with a built-in semiconductor element according to claim 1, wherein an average particle diameter of the inorganic filler is 1.0 μm or more.   The circuit board with a built-in semiconductor element according to claim 1, wherein the resin layer has a thickness of 20 to 100 μm.   A semiconductor device comprising the circuit board with a built-in semiconductor element according to claim 1.

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