JP2013131532A - Method of manufacturing semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device with reduced warpage.SOLUTION: An element mounting substrate 108 having a plurality of package areas 114 sectioned by dicing areas 112 is prepared. The element mounting substrate 108 is formed of an asymmetrical prepreg. Next, semiconductor chips 116 are mounted to the respective package areas 114 of the element mounting substrate 108. Next, the semiconductor chips 116 are molded by an encapsulation material simultaneously. Thereafter, dicing is performed along the dicing areas 112 to make the respective molded semiconductor chips 116 into individual pieces.

Description

  The present invention relates to a method for manufacturing a semiconductor device.

  In recent years, in the technical field of semiconductor packages, small packages such as CSP (Chip Size Package) and LGA (Land Grid Array) are being used in order to meet demands such as downsizing and multi-pinning.

  For these packaging methods, a MAP (Mold Array Package) method is used in which a semiconductor chip is modularized by a batch molding method, and the mounting area and manufacturing cost can be significantly reduced. The MAP method is a production method in which several tens of chips are arranged in a matrix on a large substrate, and dicing into individual packages after one-sided batch sealing (Patent Document 1 and Patent Document 2).

JP-A-8-222654 JP 2003-60126 A

  In the conventional technology such as Patent Document 1, when a semiconductor chip is mounted on an element mounting substrate, warpage occurs in the element mounting substrate due to a difference in these linear expansion coefficients. The warpage of the element mounting substrate was such that the end of the element mounting substrate warped on the opposite side of the element mounting side from the center (hereinafter referred to as a cry-type warpage).

  The present inventors considered that the conventional element mounting substrate has a target structure in which the fiber base layer is present at the center, and therefore, when the semiconductor chip is mounted, a large cry-shaped warp occurs in the element mounting substrate. That is, the element mounting substrate having a symmetrical structure has a substantially flat structure immediately before chip mounting. For this reason, it is considered that the element mounting substrate having a symmetric structure is greatly affected by the difference in coefficient of linear expansion with the semiconductor chip during mounting, and a large warp of the cry type occurs.

According to the present invention, a preparation step of preparing an element mounting substrate including a plurality of package areas partitioned by a dicing region;
A mounting step of mounting a semiconductor chip in each of the package areas of the element mounting substrate;
A molding step of simultaneously molding the semiconductor chip with a sealing material;
Dividing along the dicing region, and a singulation step of dividing each molded semiconductor chip,
Including
The element mounting substrate includes a fiber base layer obtained by impregnating a fiber base with a resin, a first resin layer formed on the element mounting surface side of the fiber base layer, and the other of the fiber base layers. Including a core material composed of a second resin layer formed on the surface side,
A method for manufacturing a semiconductor device is provided in which the thickness of the first resin layer is larger than the thickness of the second resin layer.

  According to the present invention, a semiconductor device with reduced warpage is provided.

It is process sectional drawing which shows the manufacture procedure of the semiconductor device in this Embodiment. It is process sectional drawing which shows the manufacture procedure of the semiconductor device in this Embodiment. FIG. 3 is a process top view illustrating a manufacturing procedure of the semiconductor device illustrated in FIG. It is process sectional drawing which shows the manufacture procedure of the semiconductor device in this Embodiment. It is sectional drawing which shows the manufacturing apparatus of an element mounting board | substrate. It is sectional drawing which shows the modification of an element mounting board | substrate typically.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate.

  1 to 4 are process cross-sectional views illustrating the manufacturing procedure of the semiconductor device according to the present embodiment. In the figure, wiring patterns and through holes are not shown for the sake of brevity.

  The manufacturing method of the semiconductor device 100 of the present embodiment includes the following steps. First, the element mounting substrate 108 including a plurality of package areas 114 partitioned by the dicing region 112 is prepared (hereinafter referred to as a preparation process). Next, the semiconductor chip 116 is mounted in each package area 114 of the element mounting substrate 108 (hereinafter referred to as a mounting process). Next, the semiconductor chip 116 is simultaneously molded with a sealing material (hereinafter referred to as a molding process). Dicing is performed along the dicing region 112 to divide each molded semiconductor chip 116 (hereinafter referred to as a singulation process). The element mounting substrate 108 of the present embodiment includes a fiber base layer 102 formed by impregnating a fiber base with resin, and a first resin layer 104 formed on the element mounting surface 110 side of the fiber base layer 102. And the second resin layer 106 formed on the other surface side of the fiber base layer 102, and the thickness of the first resin layer 104 is greater than the thickness of the second resin layer 106. Specified by.

First, an outline of the manufacturing process of the present embodiment will be described.
As shown in FIG. 1A, in this step, first, a prepreg 107 having an asymmetric core structure is prepared. The element mounting substrate 108 shown in FIG. 1B is obtained by subjecting the prepreg 107 to, for example, heat and pressure molding.
The element mounting substrate 108 shown in FIG. 1B has its end warped toward the element mounting surface 110 rather than the center (hereinafter referred to as a smile-type warp). The smile-type warpage occurs in the element mounting substrate 108 because the fiber base layer 102 is unevenly distributed on the side opposite to the element mounting surface 110. That is, since the thickness d1 of the first resin layer 104 on the element mounting surface 110 side is thicker than the thickness d2 of the second resin layer 106 on the opposite surface side, the linear expansion coefficient of the prepreg 107 on the element mounting surface 110 side is It becomes relatively large. Therefore, the prepreg 107 on the element mounting surface 110 side contracts relatively, and a smile-type warp as shown in FIG.

  Subsequently, as shown in FIG. 2A, a plurality of semiconductor chips 116 are mounted on the element mounting surface 110 of the element mounting substrate 108. At this time, the linear expansion coefficient on the element mounting surface 110 side on which the semiconductor chip 116 is mounted is relatively smaller than the opposite surface. That is, by making the fiber base material layer 102 unevenly distributed on the second resin layer 106 side of the element mounting substrate 108, the difference in linear expansion coefficient between both surfaces of the element mounting substrate 108 can be reduced. For this reason, it is possible to reduce the cry-shaped warpage generated on the element mounting substrate 108 during mounting.

  Next, as shown in FIG. 2B, a mold resin layer 120 covering the semiconductor chip 116 can be formed on the element mounting surface 110 of the element mounting substrate 108. Thereby, a semiconductor package is obtained. The mold resin layer 120 can reduce the warpage of the semiconductor package when the cry type warpage of the element mounting substrate 108 is small. Therefore, in the element mounting substrate 108 shown in FIG. 2B, the conventional cry type warpage is reduced. By individualizing such a semiconductor package, individual semiconductor devices 100 with reduced warpage can be obtained.

  Usually, when the film thickness of the mold resin layer or the thickness of the mounting substrate is reduced, the influence of the cry-shaped warpage during mounting increases. Even in this case, since the conventional cry-type warpage can be reduced, it is possible to suppress a decrease in secondary mountability and a decrease in mounting yield of the semiconductor device 100. Even when the diameter of the solder ball is reduced and the allowable amount of warpage is reduced, the warpage of the semiconductor device 100 can be reduced, so that the element mounting substrate 108 of the present embodiment can be used. By using the semiconductor device 100 obtained by the manufacturing process of the present embodiment, it is possible to suppress a decrease in secondary mountability and a decrease in mounting yield.

In addition, when a symmetric prepreg is used, the linear expansion coefficient on the side opposite to the element mounting surface increases, and a large cry-shaped warp occurs in the element mounting substrate in the mounting process. As a result, in the molding process, there is a possibility that the cry-shaped warpage at the time of mounting may remain on the element mounting substrate.
In contrast, in the present embodiment, since a smile-type warp is formed on the element mounting substrate 108 in the preparation step, the cry-type warp during mounting can be reduced. Thereby, in the molding process, it is possible to reduce a residual cry-shaped warp when mounted on the element mounting substrate, and it is more preferable to obtain a semiconductor device having a flat element mounting substrate.

Hereinafter, each process is explained in full detail.
(Preparation process)
(Method for manufacturing element mounting substrate)
A method for manufacturing the element mounting substrate 108 in the present embodiment will be described. FIG. 1A and FIG. 1B are cross-sectional views showing manufacturing steps of the element mounting substrate in the present embodiment.

  First, a prepreg 107 including a first resin layer 104, a fiber base layer 102, and a second resin layer 106 is prepared. In addition to the prepreg 107 shown in FIG. 1, for example, a prepreg 107 shown in FIG. 6 may be used. The prepreg 107 used in the present embodiment is not particularly limited as long as the thickness d1 of the resin layer on the element mounting surface 110 side is thicker than the thickness d2 of the resin layer on the opposite surface. That is, the prepreg 107 is an asymmetric prepreg in which the fiber base layer is unevenly distributed on the side opposite to the element mounting surface 110 (hereinafter, sometimes simply referred to as the opposite surface side).

  For example, the prepreg 107 shown in FIG. 6A has a single-layer fiber base layer 102. All of the fiber base layers 102 are unevenly distributed on the side opposite to the center line C of the prepreg 107. Further, the thickness of the fiber base layer 102 is smaller than half the film thickness of the prepreg 107.

  The prepreg 107 shown in FIG. 6B is different from FIG. 6A in that the fiber base layer 102 is disposed on the element mounting surface 110 side beyond the center line C.

  Moreover, the prepreg 107 shown in FIG.6 (c) has the 2nd layer 1st fiber base material layer 102a and the 2nd fiber base material layer 102b. That is, the prepreg 107 includes the first resin layer 104, the first fiber base layer 102a, the intermediate resin layer 122, the second fiber base layer 102b, and the second resin layer 106. Also in this case, the thickness d1 from the element mounting surface 110 to the first fiber base layer 102a is designed to be thicker than the thickness d2 from the opposite face to the second fiber base layer 102b. In FIG. 6C, one of the first fiber base layer 102a and the second fiber base layer 102b may be formed beyond the center line C, but the second fiber on the opposite surface side. A mode in which the base material layer 102b is formed beyond the center line C is preferable. Thereby, the difference in the linear expansion coefficient between the element mounting surface 110 side and the opposite surface side during mounting can be reduced.

  Furthermore, the prepreg 107 shown in FIG. 6D has three fiber base layers. That is, the prepreg 107 includes the first resin layer 104, the first fiber base layer 102a, the intermediate resin layer 124, the intermediate fiber base layer 102c, the intermediate resin layer 126, the second fiber base layer 102b, and the second resin layer 106. Have Thus, the prepreg 107 of the present embodiment may have a plurality of fiber base layers, and the thickness from the first fiber base layer 102a on the element mounting surface 110 side of the uppermost layer to the element mounting surface 110. It is sufficient that the length d1 is designed to be larger than the thickness d2 from the second fiber base layer 102b on the opposite side of the lowermost layer to the opposite side.

  In the prepreg 107 of the present embodiment, d1 / d2 is not particularly limited as long as d1> d2, but is preferably 1.5 or more, and more preferably 2.0 or more, for example. By setting d1 / d2 within the above range, it is possible to reduce the cry-type warpage during mounting of the semiconductor chip. In addition, even when semiconductor chips are arranged on the element mounting surface 110 at a high density, it is possible to reduce the cry-shaped warpage.

(Manufacturing method of prepreg)
Below, the manufacturing method of the prepreg in this embodiment is demonstrated.
The prepreg 107 is a sheet-like material provided with a fiber base layer and a resin layer, which is obtained by impregnating a fiber base with one or more resin compositions and then semi-curing. A sheet-like material having such a structure is preferable because it is excellent in various characteristics such as dielectric properties, mechanical and electrical connection reliability under high temperature and high humidity, and suitable for manufacturing an element mounting substrate for a circuit board.

  The method for impregnating the fiber base material with the resin composition used in the present embodiment is not particularly limited. For example, the resin composition is dissolved in a solvent to prepare a resin varnish, and the fiber base material is immersed in the resin varnish. Examples thereof include a method, a coating method using various coaters, a spraying method, and a method of laminating a resin layer with a supporting substrate. Among these, the method of immersing the fiber base material in the resin varnish is preferable. Thereby, the impregnation property of the resin composition with respect to the fiber base material can be improved. In addition, when a fiber base material is immersed in a resin varnish, a normal impregnation coating equipment can be used.

  In particular, when the thickness of the fiber substrate is 0.1 mm or less, a method of laminating with a film-like resin layer from both sides of the fiber substrate is preferable. Thereby, the impregnation amount of the resin composition with respect to the fiber base material can be freely adjusted, and the moldability of the prepreg can be further improved. In addition, when laminating a film-like resin layer, it is more preferable to use a vacuum laminating apparatus or the like.

Specifically, examples of the method for producing the prepreg include the following methods.
FIG. 5 is a cross-sectional view showing a method for producing a prepreg. Here, the carrier material 5a, 5b is manufactured in advance, and after laminating the carrier material 5a, 5b on the fiber base material 11, a method of peeling the carrier film will be specifically described.

A carrier material 5a in which the first resin composition is previously applied to the carrier film and a carrier material 5b in which the second resin composition is applied to the carrier film are manufactured. Next, using the vacuum laminating apparatus 60, the carrier materials 5a and 5b are overlapped from both sides of the fiber base material under reduced pressure, and bonded with a laminating roll 61 heated to a temperature at which the resin composition melts as necessary, The fiber base material 11 is impregnated with the resin composition coated on the carrier film. By bonding under reduced pressure, even if there is an unfilled portion inside the fiber base material 11 or at the joint portion between the resin layer of the carrier material 5a, 5b and the fiber base material 11, this is reduced by a vacuum void or substantially It can be a vacuum void.
As another device for joining the fiber base material 11 and the carrier materials 5a and 5b under such a reduced pressure, for example, a vacuum box device, a vacuum becquerel device, or the like can be used.

  Next, after bonding the fiber base material 11 and the carrier materials 5a and 5b, heat treatment is performed at a temperature equal to or higher than the melting temperature of the resin applied to the carrier material by the hot air drying device 62. Thereby, the decompression void etc. which have occurred in the joining process under reduced pressure can be almost eliminated. As another method for heat treatment, for example, an infrared heating device, a heating roll device, a plate-shaped hot platen pressing device, or the like can be used.

After laminating the carrier materials 5a and 5b to the fiber substrate 11, the carrier film is peeled off. By this method, the resin composition is supported on the fiber base material 11, and the prepreg 21 in which the fiber base material 11 is built is obtained.
If said method is used, the prepreg in which the fiber base material layer was unevenly distributed in the thickness direction can be produced by adjusting the thickness of the resin composition of the carrier materials 5a and 5b.

  In addition to the above method, the method described in paragraphs 0022 to 0041 of Reference Document 1 (Japanese Patent Laid-Open No. 2010-275337) can be used. This will be specifically described below.

  The fiber base material is conveyed so as to pass between the two die coaters to a coating machine provided with the first coating device and the second coating device, which are two die coaters, one on each of the two surfaces. Resin varnish is applied. The first coating apparatus and the second coating apparatus may use the same die coater or different ones. Moreover, it may replace with a 1st coating apparatus and a 2nd coating apparatus, and may use a roll coater. Moreover, although it is preferable that the coating distance L and the tip overlap distance D have a certain distance, they may not have a certain distance.

  The first coating device and the second coating device each have a coating tip, and each coating tip is formed elongated in the width direction of the fiber substrate. And the 1st coating front-end | tip part which is a coating front-end | tip part of a 1st coating apparatus protrudes toward one surface of a fiber base material, and the 2nd coating front-end | tip which is a coating front-end | tip part of a 2nd coating apparatus The part protrudes toward the other surface of the fiber base material. Thereby, in the application of the resin varnish, the first coating tip is in contact with one surface of the fiber base material via the resin varnish, and the second coating tip is the other surface of the fiber base material. And contact through the resin varnish.

The discharge amount per unit time of the resin varnish discharged from the first coating apparatus and the second coating apparatus may be the same or different. By varying the discharge amount per unit time of the resin varnish, the thickness of the resin varnish to be applied can be individually controlled on one side and the other side of the fiber base, and the layer thickness of the resin layer can be controlled. Adjustment can be performed easily.
A prepreg is manufactured by heating at a predetermined temperature in a dryer to volatilize the solvent of the applied resin varnish 4 and to semi-cur the resin composition.

  In addition, when the fiber base material is immersed in the resin varnish, the solvent used in the resin varnish preferably exhibits good solubility with respect to the resin component in the resin composition. May be used. Examples of the solvent exhibiting good solubility include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, tetrahydrofuran, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, ethylene glycol, cellosolve and carbitol.

The thickness of the first resin layer 104 of the asymmetric prepreg is not particularly limited, but is preferably 1 μm or more and 15 μm or less, for example. On the other hand, the thickness of the second resin layer 106 is not particularly limited, but is preferably 2.3 μm or more and 100 μm or less, for example.
Here, the thickness of the resin layer is the distance from the interface between the fiber base layer and the resin layer to the opposite interface of the resin layer, and does not include the resin impregnated in the fiber base layer.

  The solid content of the resin varnish is not particularly limited, but is preferably 40% by weight to 80% by weight, and particularly preferably 50% by weight to 65% by weight. Thereby, the impregnation property to the fiber base material of the resin varnish can further be improved. A prepreg can be obtained by impregnating a fiber base material with a resin composition and drying at a predetermined temperature, for example, 80 ° C. or more and 200 ° C. or less.

Next, returning to FIG. 1A, the material constituting the prepreg 107 in this embodiment will be described in detail.
(Fiber substrate layer)
In the present embodiment, the fiber substrate used for the fiber substrate layer 102 is not particularly limited, but a glass fiber substrate such as glass cloth, polybenzoxazole resin fiber, polyamide resin fiber, aromatic polyamide resin fiber, Consists of polyamide resin fibers such as wholly aromatic polyamide resin fibers, polyester resin fibers, aromatic polyester resin fibers, polyester resin fibers such as wholly aromatic polyester resin fibers, polyimide resin fibers, and fluororesin fibers. Organic fiber base materials such as paper base materials mainly composed of synthetic fiber base materials, kraft paper, cotton linter paper, mixed paper of linter and kraft pulp, and the like. Among these, glass cloth is particularly preferable from the viewpoint of strength and water absorption. Moreover, the thermal expansion coefficient of the resin layer can be further reduced by using glass cloth.

  As glass which comprises 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.

The glass fiber substrate used in the present embodiment preferably has a basis weight (weight of the fiber substrate per 1 m ² ) of 4 g / m ² or more and 150 g / m ² or less, more preferably 8 g / m. ² or more and 110 g / m ² or less, more preferably 12 g / m ² or more and 60 g / m ² or less, more preferably 12 g / m ² or more and 30 g / m ² or less, more preferably 12 g / m ² or more and 24 g / m ² or less. is there.

  When the basis weight exceeds the above upper limit value, the impregnation property of the resin composition in the fiber base material is lowered, and there is a risk that the strand void or the insulation reliability may be lowered, and carbon dioxide, UV, excimer, etc. There is a risk that it is difficult to form a through hole. On the other hand, when the basis weight is lower than the lower limit, the strength of the glass cloth or prepreg is lowered, there is a risk that the handling will be lowered, the preparation of the prepreg may be difficult, and the effect of reducing the warpage of the substrate may be reduced.

  Among the glass fiber substrates, a glass fiber substrate having a linear expansion coefficient of 6 ppm / ° C. or less is particularly preferable, and a glass fiber substrate having 3.5 ppm / ° C. or less is more preferable. By using the glass fiber base material having such a linear expansion coefficient, the warpage of the element mounting substrate of the present embodiment can be further suppressed.

  Furthermore, the fiber base material used in the present embodiment preferably has a Young's modulus of 60 GPa to 100 GPa, more preferably 65 GPa to 92 GPa, and still more preferably 86 GPa to 92 GPa. By using a glass fiber base material having such a Young's modulus, for example, deformation of the wiring board due to reflow heat during semiconductor mounting can be effectively suppressed, so that the connection reliability of electronic components is further improved.

  The glass fiber substrate used in the present embodiment preferably has a dielectric constant at 1 MHz of 3.8 to 7.0, more preferably 3.8 to 6.8, and still more preferably 3. It is 8 or more and 5.5 or less. By using a glass fiber substrate having such a dielectric constant, the dielectric constant of the element mounting substrate can be further reduced, which is suitable for a semiconductor package using a high-speed signal.

  For example, E glass, S glass, NE glass, T glass, UN glass and the like are suitably used as the glass fiber base material having the above-described linear expansion coefficient, Young's modulus, and dielectric constant.

  The fiber base layer 102 in the element mounting substrate 108 is a layer formed by impregnating the above-mentioned fiber base with the resin composition constituting the first resin layer 104 and the second resin layer 106. The thickness of the layer can be considered as the thickness of the fiber substrate.

  Although the thickness of a fiber base material layer is not specifically limited, It is preferable that they are 5 micrometers or more and 100 micrometers or less, More preferably, they are 10 micrometers or more and 60 micrometers or less, More preferably, they are 12 micrometers or more and 35 micrometers or less. By using the fiber base material having such a thickness, the handling property at the time of manufacturing the prepreg is further improved, and the warp reduction effect is particularly remarkable.

  When the thickness of the fiber base layer exceeds the above upper limit, the impregnation property of the resin composition in the fiber base material is lowered, and there is a risk that the strand void and the insulation reliability may be lowered. Carbon dioxide, UV, excimer It may be difficult to form a through hole using a laser. In addition, when the thickness of the fiber base layer is lower than the lower limit, the strength of the fiber base or prepreg is lowered, the handling may be difficult, the preparation of the prepreg may be difficult, and the warping effect of the substrate may be reduced. There is a fear.

  Further, the number of fiber base materials used is not limited to one, and a plurality of thin fiber base materials can be used in a stacked manner. In addition, when using a plurality of fiber base materials in piles, the total thickness only needs to satisfy the above range.

  The element mounting substrate 108 has a fiber substrate layer formed by impregnating a fiber substrate such as a glass fiber substrate with a resin composition, thereby being excellent in low linear expansion coefficient and high elastic modulus, a thin multilayer wiring board, A semiconductor package in which a semiconductor chip is mounted on the multilayer wiring board can be obtained with less warpage and excellent heat resistance and thermal shock reliability. Among them, high strength, low water absorption, and low thermal expansion can be achieved by having a fiber base layer formed by impregnating a glass fiber base with a resin composition.

(Resin composition)
The resin composition impregnated into the fiber base material is not particularly limited, but preferably has a low linear expansion coefficient and a high elastic modulus and is excellent in thermal shock reliability.
The glass transition temperature of the resin composition is preferably 160 ° C. or higher and 270 ° C. or lower, and more preferably 180 ° C. or higher and 240 ° C. or lower. By using the resin composition having such a glass transition temperature, an effect of further improving the lead-free solder reflow heat resistance can be obtained.

Specific thermosetting resins include, for example, novolac type phenolic resins such as phenol novolak resin, cresol novolac resin, bisphenol A novolak resin, unmodified resole phenolic resin, oil modified resole modified with tung oil, linseed oil, walnut oil, etc. Phenol resin such as phenolic resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol E type epoxy resin, bisphenol M type epoxy resin, bisphenol P type epoxy resin, bisphenol Bisphenol type epoxy resin such as Z type epoxy resin, novolak type epoxy resin such as phenol novolac type epoxy resin, cresol novolac type epoxy resin, biffe Type epoxy resin, biphenyl aralkyl type epoxy resin, aryl alkylene type epoxy resin, naphthalene type epoxy resin, anthracene type epoxy resin, phenoxy type epoxy resin, dicyclopentadiene type epoxy resin, norbornene type epoxy resin, adamantane type epoxy resin, fluorene Type epoxy resin, epoxy resin, urea (urea) resin, resin having triazine ring such as melamine resin, unsaturated polyester resin, bismaleimide resin, polyurethane resin, diallyl phthalate resin, silicone resin, resin having benzoxazine ring, Examples include cyanate resin, polyimide resin, polyamideimide resin, and benzocyclobutene resin.
One of these may be used alone, two or more having different weight average molecular weights may be used in combination, and one or two or more thereof and a prepolymer thereof may be used in combination.

  Among these, cyanate resins (including prepolymers of cyanate resins) are particularly preferable. By using cyanate resin, the thermal expansion coefficient of the resin layer can be reduced. Further, the cyanate resin is excellent in electrical characteristics (low dielectric constant, low dielectric loss tangent), mechanical strength, and the like.

  Examples of the cyanate resin that can be used include those obtained by reacting a cyanogen halide compound with phenols, and those obtained by prepolymerization by a method such as heating as required. Specifically, bisphenol cyanate resins such as novolac type cyanate resin, bisphenol A type cyanate resin, bisphenol E type cyanate resin, tetramethylbisphenol F type cyanate resin, naphthol aralkyl type polyvalent naphthols, and cyanogen halides Cyanate resin, dicyclopentadiene-type cyanate resin, biphenylalkyl-type cyanate resin, and the like obtained by the above reaction. Among these, novolac type cyanate resin is preferable. By using the novolac type cyanate resin, the crosslink density is increased and the heat resistance is improved. Accordingly, the flame retardancy of the resin composition and the like can be improved.

  The reason for this is that the novolak 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 resin layer made of prepreg or the like has a thickness of 0.6 mm or less, the element mounting substrate including the resin layer produced by curing the novolac-type cyanate resin has excellent rigidity. In particular, since such an element mounting substrate is excellent in rigidity during heating, it is also excellent in reliability when mounting a semiconductor element.

  As a novolak-type cyanate resin, what is shown by the following general formula (I) can be used, for example.

  The average repeating unit n of the novolak-type cyanate resin represented by the general formula (I) is an arbitrary integer and is not particularly limited, but is preferably 1 or more and 10 or less, particularly preferably 2 or more and 7 or less. If the average repeating unit n is too small, the heat resistance of the novolac-type cyanate resin decreases, and the low-mer may desorb and volatilize when heated. Moreover, when the average repeating unit n is too large, the melt viscosity becomes too high, and the moldability of the resin layer may be lowered.

  As the cyanate resin, a naphthol type cyanate resin represented by the following general formula (II) is also preferably used. The naphthol type cyanate resin represented by the following general formula (II) includes naphthols such as α-naphthol or β-naphthol, p-xylylene glycol, α, α′-dimethoxy-p-xylene, 1,4-di ( It is obtained by condensing naphthol aralkyl resin obtained by reaction with 2-hydroxy-2-propyl) benzene and cyanic acid. In the general formula (II), n is more preferably 10 or less. When n is 10 or less, the resin viscosity does not increase, the impregnation property to the base material is good, and the performance as an element mounting substrate tends not to deteriorate. In addition, intramolecular polymerization hardly occurs at the time of synthesis, the liquid separation property at the time of washing with water tends to be improved, and the decrease in yield tends to be prevented.

（式中、Ｒは水素原子またはメチル基を示し、ｎは１以上の整数を示す。）

(In the formula, R represents a hydrogen atom or a methyl group, and n represents an integer of 1 or more.)

  As the cyanate resin, a dicyclopentadiene type cyanate resin represented by the following general formula (III) is also preferably used. In the dicyclopentadiene type cyanate resin represented by the following general formula (III), n in the following general formula (III) is more preferably 0 or more and 8 or less. When n is 8 or less, the resin viscosity is not increased, the impregnation property to the base material is good, and the performance as the element mounting substrate can be prevented from being lowered. Moreover, by using a dicyclopentadiene type cyanate resin, it is excellent in low hygroscopicity and chemical resistance.

（ｎは０以上８以下の整数を示す。）

(N represents an integer of 0 or more and 8 or less.)

Although the weight average molecular weight (Mw) of cyanate resin is not specifically limited, For example, Mw 500-4,500 is preferable, and 600-3,000 is especially preferable. If Mw is too small, tackiness may occur when the resin layer is produced, and when the resin layers come into contact with each other, they may adhere to each other or transfer of the resin may occur. Moreover, when Mw is too large, the reaction becomes too fast, and when it is used as a circuit board, a molding defect may occur or the interlayer peel strength may decrease.
Mw such as cyanate resin can be measured by, for example, GPC (gel permeation chromatography, standard substance: converted to polystyrene).

  Moreover, although it does not specifically limit, cyanate resin may be used individually by 1 type, may use together 2 or more types which have different Mw, and uses 1 type or 2 types and those prepolymers together. May be.

  The content of the thermosetting resin contained in the resin composition is not particularly limited as long as it is appropriately adjusted according to the purpose, but is preferably 5 wt% or more and 90 wt% or less based on the entire resin composition, Further, it is preferably 10% by weight or more and 80% by weight or less, and particularly preferably 20% by weight or more and 50% by weight or less. If the content of the thermosetting resin is too small, the handling properties of the prepreg may be lowered or it may be difficult to form a resin layer. If the content is too large, the strength and flame retardancy of the resin layer will be reduced. In some cases, the linear expansion coefficient of the resin layer increases, and the effect of reducing the warpage of the element mounting substrate may decrease.

  Moreover, it is preferable that a resin composition contains an inorganic filler. Thereby, even more excellent strength can be imparted even if the element mounting substrate is thinned. Furthermore, the low thermal expansion of the element mounting substrate can be further improved.

  Examples of inorganic fillers include silicates such as talc, calcined clay, unfired clay, mica and glass, oxides such as titanium oxide, alumina, boehmite, silica and fused silica, calcium carbonate, magnesium carbonate and hydrotalcite. Carbonates such as, 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, Examples thereof include borates such as calcium borate and sodium borate, nitrides such as aluminum nitride, boron nitride, silicon nitride and carbon nitride, titanates such as strontium titanate and barium titanate.

  As the inorganic filler, one of these may be used alone, or two or more may be used in combination. Among these, silica is particularly preferable, and fused silica (especially spherical fused silica) is preferable in terms of excellent low thermal expansion. The fused silica has a crushed shape and a spherical shape. In order to ensure the impregnation property to the fiber base material, it is possible to adopt a usage method suitable for the purpose, such as using spherical silica to lower the melt viscosity of the resin composition.

The average particle diameter of the inorganic filler is not particularly limited, but is preferably 0.01 μm or more and 5.0 μm or less, and particularly preferably 0.1 μm or more and 2.0 μm or less. If the particle size of the inorganic filler is too small, the viscosity of the varnish is increased, which may affect the workability during the production of the resin layer. In addition, when the particle size of the inorganic filler is too large, a phenomenon 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).

  The inorganic filler is not particularly limited, but an inorganic filler having a monodispersed average particle diameter may be used, or an inorganic filler having a polydispersed average particle diameter may be used. Furthermore, one type or two or more types of inorganic fillers having an average particle size of monodispersed and / or polydispersed may be used in combination.

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

  Although the lower limit of content of an inorganic filler is not specifically limited, 20 weight% or more is preferable based on the whole resin composition, 30 weight% or more is more preferable, and 50 weight% or more is further more preferable. Although the upper limit of content of an inorganic filler is not specifically limited, 80 weight% or less is preferable based on the whole resin composition, and 75 weight% or less is more preferable. When the content is within the above range, particularly low thermal expansion and low water absorption can be achieved. In particular, the warpage of the element mounting substrate can be reduced.

  The resin composition used in the present embodiment can also contain a rubber component, and for example, rubber particles can be used. Preferable examples of the rubber particles include core-shell type rubber particles, crosslinked acrylonitrile butadiene rubber particles, crosslinked styrene butadiene rubber particles, acrylic rubber particles, and silicone particles.

  The core-shell type rubber particles are rubber particles having a core layer and a shell layer. For example, a two-layer structure in which an outer shell layer is formed of a glassy polymer and an inner core layer is formed of a rubbery polymer, or Examples include a three-layer structure in which the outer shell layer is made of a glassy polymer, the intermediate layer is made of a rubbery polymer, and the core layer is made of a glassy polymer. The glassy polymer layer is made of, for example, a polymer of methyl methacrylate, and the rubbery polymer layer is made of, for example, a butyl acrylate polymer (butyl rubber). Specific examples of the core-shell type rubber particles include Staphyloid AC3832, AC3816N (trade names, manufactured by Ganz Kasei Co., Ltd.), and Metabrene KW-4426 (trade names, manufactured by Mitsubishi Rayon Co., Ltd.). Specific examples of the crosslinked acrylonitrile butadiene rubber (NBR) particles include XER-91 (average particle size: 0.5 μm, manufactured by JSR).

  Specific examples of the crosslinked styrene butadiene rubber (SBR) particles include XSK-500 (average particle size 0.5 μm, manufactured by JSR). Specific examples of the acrylic rubber particles include methabrene W300A (average particle size 0.1 μm), W450A (average particle size 0.2 μm) (manufactured by Mitsubishi Rayon Co., Ltd.), and the like.

  The silicone particles are not particularly limited as long as they are rubber elastic fine particles formed of organopolysiloxane. For example, fine particles made of silicone rubber (organopolysiloxane crosslinked elastomer) itself and a core portion made of silicone mainly composed of two-dimensional crosslinks. Examples thereof include core-shell structure particles coated with silicone mainly composed of a three-dimensional crosslinking type. As silicone rubber fine particles, commercially available products such as KMP-605, KMP-600, KMP-597, KMP-594 (manufactured by Shin-Etsu Chemical Co., Ltd.), Trefil E-500, Trefil E-600 (manufactured by Toray Dow Corning), etc. Can be used.

  The content of the rubber particles is not particularly limited, but is preferably 20% by weight or more and 80% by weight or less, particularly preferably 30% by weight or more and 75% by weight or less based on the entire resin composition, including the above inorganic filler. . When the content is within the range, particularly low water absorption can be achieved.

  In addition to using cyanate resin (particularly novolak-type cyanate resin, naphthol-type cyanate resin, dicyclopentadiene-type cyanate resin) as a thermosetting resin, an epoxy resin (substantially free of halogen atoms) may be used, You may use together. Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol E type epoxy resin, bisphenol S type epoxy resin, bisphenol M type epoxy resin, bisphenol P type epoxy resin, bisphenol Z type epoxy resin and the like. Type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins and other novolak type epoxy resins, biphenyl type epoxy resins, xylylene type epoxy resins, biphenyl aralkyl type epoxy resins and other aryl alkylene type epoxy resins, naphthalene type epoxy resins, Binaphthyl type epoxy resin, anthracene type epoxy resin, phenoxy type epoxy resin, dicyclopentadiene type epoxy resin, norbornene Type epoxy resins, adamantane type epoxy resins, and fluorene type epoxy resins.

  As an epoxy resin, one of these may be used alone, or two or more having different weight average molecular weights may be used in combination, or one or two or more and those prepolymers may be used in combination. May be.

  Among these epoxy resins, aryl alkylene type epoxy resins are particularly preferable. Thereby, moisture-absorbing solder heat resistance and flame retardance can be further improved.

  The aryl alkylene type epoxy resin refers to an epoxy resin having one or more aryl alkylene 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. A biphenyl dimethylene type | mold epoxy resin can be shown, for example with the following general formula (IV).

  The average repeating unit n of the biphenyldimethylene type epoxy resin represented by the general formula (IV) is an arbitrary integer, and is not particularly limited, but is preferably 1 or more and 10 or less, particularly preferably 2 or more and 5 or less. When the average repeating unit n is too small, the biphenyl dimethylene type epoxy resin is easily crystallized, and the solubility in a general-purpose solvent is relatively lowered, which may make handling difficult. On the other hand, if the average repeating unit n is too large, the fluidity of the resin is lowered, which may cause molding defects.

  As the epoxy resin other than the above, a novolak type epoxy resin having a condensed ring aromatic hydrocarbon structure is preferable. Thereby, heat resistance and low thermal expansibility can further be improved.

  The novolak type epoxy resin having a condensed ring aromatic hydrocarbon structure is a novolak type epoxy resin having a naphthalene, anthracene, phenanthrene, tetracene, chrysene, pyrene, triphenylene, and tetraphen or other condensed ring aromatic hydrocarbon structure. . The novolac type epoxy resin having a condensed ring aromatic hydrocarbon structure is excellent in low thermal expansion because a plurality of aromatic rings can be regularly arranged. Moreover, since the glass transition temperature is also high, it is excellent in heat resistance. Furthermore, since the molecular weight of the repeating structure is large, it is superior in flame retardancy compared to conventional novolak type epoxies, and the weakness of cyanate resin can be improved by combining with cyanate resin. Therefore, when used in combination with a cyanate resin, the glass transition temperature is further increased, so that the lead-free compatible mounting reliability is excellent.

  The novolak-type epoxy resin having a condensed ring aromatic hydrocarbon structure is obtained by epoxidizing a novolak-type phenol resin synthesized from a phenol compound, a formaldehyde compound, and a condensed ring aromatic hydrocarbon compound.

  The phenol compound is not particularly limited, but examples thereof include cresols such as phenol, o-cresol, m-cresol, and p-cresol, 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2, 6-xylenol, 3,4-xylenol, xylenols such as 3,5-xylenol, trimethylphenols such as 2,3,5 trimethylphenol, ethyl such as o-ethylphenol, m-ethylphenol, p-ethylphenol Phenols, alkylphenols such as isopropylphenol, butylphenol, t-butylphenol, o-phenylphenol, m-phenylphenol, p-phenylphenol, catechol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene , 2,7-naphthalene diols such as dihydroxynaphthalene, resorcinol, catechol, hydroquinone, pyrogallol, polyhydric phenols such as fluoro Guru Singh, alkyl resorcinol, alkyl catechol, alkyl polyhydric phenols such as alkyl hydroquinone. Of these, phenol is preferable from the viewpoint of cost and the effect on the decomposition reaction.

  The aldehyde compound is not particularly limited. For example, formaldehyde, paraformaldehyde, trioxane, acetaldehyde, propionaldehyde, polyoxymethylene, chloral, hexamethylenetetramine, furfural, glyoxal, n-butyraldehyde, caproaldehyde, allylaldehyde, Examples include benzaldehyde, crotonaldehyde, acrolein, tetraoxymethylene, phenylacetaldehyde, o-tolualdehyde, salicylaldehyde, dihydroxybenzaldehyde, trihydroxybenzaldehyde, 4-hydroxy-3-methoxyaldehyde paraformaldehyde and the like.

  Although the condensed ring aromatic hydrocarbon compound is not particularly limited, for example, naphthalene derivatives such as methoxynaphthalene and butoxynaphthalene, anthracene derivatives such as methoxyanthracene, phenanthrene derivatives such as methoxyphenanthrene, other tetracene derivatives, chrysene derivatives, pyrene derivatives, Derivatives such as triphenylene and tetraphen derivatives are mentioned.

  The novolak-type epoxy resin having a condensed ring aromatic hydrocarbon structure is not particularly limited, and examples thereof include methoxynaphthalene-modified orthocresol novolak epoxy, butoxynaphthalene-modified meta (para) cresol novolak epoxy, and methoxynaphthalene-modified novolak epoxy. . Among these, a novolac type epoxy resin having a condensed ring aromatic hydrocarbon structure represented by the following formula (V) is preferable.

(In the formula, Ar is a condensed ring aromatic hydrocarbon group, R may be the same or different from each other, and is a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, a halogen element, a phenyl group, A group selected from an aryl group such as a benzyl group and an organic group containing glycidyl ether, n, p and q are integers of 1 or more, and the values of p and q may be the same or different for each repeating unit. May be.)

(Ar in the formula (V) is a structure represented by (Ar1) to (Ar4) in the formula (VI), and Rs in the formula (VI) may be the same or different from each other. It is often a group selected from a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms or a halogen element, an aryl group such as a phenyl group and a benzyl group, and an organic group including glycidyl ether.)

  Furthermore, as an epoxy resin other than the above, a naphthol type epoxy resin is preferable. Thereby, heat resistance and low thermal expansibility can further be improved. As a naphthol type epoxy resin, it can show by the following general formula (VII), for example.

（ｎは平均１以上６以下の数を示し、Ｒはグリシジル基または炭素数１以上１０以下の炭化水素基を示す。）

(N represents an average number of 1 to 6, and R represents a glycidyl group or a hydrocarbon group having 1 to 10 carbon atoms.)

  The content of the epoxy resin is not particularly limited, but is preferably 1% by weight or more and 55% by weight or less, and particularly preferably 2% by weight or more and 40% by weight or less based on the entire resin composition. If the content of the epoxy resin is too small, the reactivity of the cyanate resin may decrease, or the moisture resistance of the product obtained may decrease. If the content is too large, the heat resistance may decrease.

  The weight average molecular weight (Mw) of the epoxy resin is not particularly limited, but is preferably from 500 to 20,000, particularly preferably from 800 to 15,000. If the Mw is too small, tackiness may occur in the resin layer. If the Mw is too large, the impregnation property to the fiber base material may be lowered during the production of the resin layer, and a uniform product may not be obtained. The Mw of the epoxy resin can be measured by GPC, for example.

  Cyanate resins (especially novolac-type cyanate resins, naphthol-type cyanate resins, dicyclopentadiene-type cyanate resins) and epoxy resins (arylalkylene-type epoxy resins, especially biphenyldimethylene-type epoxy resins, condensed ring aromatic hydrocarbons) In the case of using a novolak type epoxy resin or a naphthol type epoxy resin having a structure, it is preferable to use a phenol resin. Examples of the phenol resin include novolac type phenol resins, resol type phenol resins, aryl alkylene type phenol resins, and the like. As a phenol resin, one of these may be used alone, two or more having different weight average molecular weights may be used in combination, and one or two or more thereof and a prepolymer thereof may be used in combination. May be. Among these, aryl alkylene type phenol resins are particularly preferable. Thereby, moisture absorption solder heat resistance can be improved further.

  Examples of the aryl alkylene type phenol resin include a xylylene type phenol resin and a biphenyl dimethylene type phenol resin. A biphenyl dimethylene type phenol resin can be shown by the following general formula (VIII), for example.

  The repeating unit n of the biphenyldimethylene type phenol resin represented by the general formula (VIII) is an arbitrary integer and is not particularly limited, but is preferably 1 or more and 12 or less, particularly preferably 2 or more and 8 or less. If the average repeating unit n is too small, the heat resistance may decrease. On the other hand, if the average repeating unit n is too large, the compatibility with other resins is lowered, and workability may be lowered.

  Cyanate resin (especially novolac-type cyanate resin, naphthol-type cyanate resin, dicyclopentadiene-type cyanate resin) and epoxy resin (arylalkylene-type epoxy resin, especially biphenyldimethylene-type epoxy resin, condensed ring aromatic hydrocarbon structure) A combination of a novolac type epoxy resin or a naphthol type epoxy resin) and an arylalkylene type phenol resin can control the crosslinking density and easily control the reactivity.

  The content of the phenol resin is not particularly limited, but is preferably 1% by weight or more and 55% by weight or less, and particularly preferably 5% by weight or more and 40% by weight or less based on the entire resin composition. If the content of the phenol resin is too small, the heat resistance may be lowered, and if it is too large, the low thermal expansion property may be impaired.

  Although the weight average molecular weight (Mw) of a phenol resin is not specifically limited, Mw is 400 or more and 18,000 or less, and 500 or more and 15,000 or less are especially preferable. If Mw is too small, tackiness may occur in the resin layer. If Mw is too large, the impregnation property to the fiber base material may be lowered during the production of the resin layer, and a uniform product may not be obtained. The Mw of the phenol resin can be measured by GPC, for example.

  Furthermore, cyanate resins (especially novolac-type cyanate resins, naphthol-type cyanate resins, dicyclopentadiene-type cyanate resins), phenol resins (arylalkylene-type phenol resins, especially biphenyldimethylene-type phenol resins), and epoxy resins (arylalkylene-type epoxy resins) In particular, when a board (particularly a circuit board) is produced using a combination with a biphenyldimethylene type epoxy resin, a novolak type epoxy resin having a condensed ring aromatic hydrocarbon structure, or a naphthol type epoxy resin), it has excellent dimensional stability. Sex can be obtained.

  In addition, additives such as a coupling agent, a curing accelerator, a curing agent, a thermoplastic resin, and an organic filler can be appropriately blended in the resin composition as necessary. The resin composition used in the present invention can be suitably used in a liquid form in which the above components are dissolved and / or dispersed with an organic solvent or the like.

  By using the coupling agent, the wettability of the interface between the thermosetting resin and the inorganic filler is improved, and the resin composition can be uniformly fixed to the fiber substrate. Therefore, it is preferable to use a coupling agent, and heat resistance, particularly solder heat resistance after moisture absorption can be improved.

  As the coupling agent, any of those usually used as a coupling agent can be used. Specifically, an epoxy silane coupling agent, a cationic silane coupling agent, an aminosilane coupling agent, a titanate coupling agent, and silicone. It is preferable to use one or more coupling agents selected from oil-type coupling agents. Thereby, wettability with the interface of an indefinite 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 specific surface area of the inorganic filler, but is preferably 0.05 part by weight or more and 3 parts by weight or less, particularly 0.1 part by weight with respect to 100 parts by weight of the inorganic filler. The amount is preferably 2 parts by weight or more and 2 parts by weight or less. If the content of the coupling agent is too small, the inorganic filler cannot be sufficiently coated and the effect of improving the heat resistance may be reduced. If the content is too large, the reaction may be affected, and the bending strength may be reduced. .

  A well-known thing can be used as a 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-ethylimidazole, 2-phenyl-4-methyl-5-hydroxy Onium salt compounds such as imidazoles such as imidazole and 2-phenyl-4,5-dihydroxyimidazole, phenolic compounds such as phenol, bisphenol A and nonylphenol, and organic acids such as acetic acid, benzoic acid, salicylic acid and paratoluenesulfonic acid. , Or a mixture thereof. As the curing accelerator, one kind including these derivatives may be used alone, or two or more kinds including these derivatives may be used in combination.

  The onium salt compound is not particularly limited, and for example, an onium salt compound represented by the following general formula (IX) can be used.

(Wherein P is a phosphorus atom, R 1, R 2, R 3 and R 4 are each an organic group having a substituted or unsubstituted aromatic ring or heterocyclic ring, or a substituted or unsubstituted aliphatic group, and are identical to each other. A- represents an anion of an n (n ≧ 1) -valent proton donor having at least one proton that can be released outside the molecule, or a complex anion thereof.

  Although content of a hardening accelerator is not specifically limited, 0.01 to 5 weight% of the whole resin composition is preferable, and 0.1 to 2 weight% is especially preferable. If the content is too small, the effect of promoting curing may not appear, and if the content is too large, the preservability of the resin layer may be lowered.

  In the resin composition, phenoxy resin, polyimide resin, polyamideimide resin, polyphenylene oxide resin, polyethersulfone resin, polyester resin, polyethylene resin, polystyrene resin and other thermoplastic resins, styrene-butadiene copolymer, styrene-isoprene copolymer Polystyrene thermoplastic elastomers such as coalescence, polyolefin thermoplastic elastomers, polyamide elastomers, thermoplastic elastomers such as polyester elastomers, and diene elastomers such as polybutadiene, epoxy modified polybutadiene, acrylic modified polybutadiene, and methacrylic modified polybutadiene are used in combination. May be.

  Examples of the phenoxy resin include a phenoxy resin having a bisphenol skeleton, a phenoxy resin having a naphthalene skeleton, a phenoxy resin having an anthracene 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. Thereby, the glass transition temperature of the phenoxy resin can be increased due to the rigidity of the biphenyl skeleton, and the adhesion between the phenoxy resin and the metal can be improved due to the presence of the bisphenol S skeleton. As a result, the heat resistance of the element mounting board can be improved, and the adhesion of the wiring layer to the element mounting board can be improved when the circuit board 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 of the wiring layer to the element mounting substrate can be further improved when the circuit board is manufactured.
It is also preferable to use a phenoxy resin having a bisphenolacetophenone structure represented by the following general formula (X).

(In the formula, R1 may be the same or different, and is a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms or a group selected from halogen elements, and R2 is a hydrogen atom, 1 carbon atom) And a group selected from a hydrocarbon group having 10 or less or a halogen element, R3 is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and m is an integer of 0 to 5).

  Since the phenoxy resin containing a bisphenol acetophenone structure has a bulky structure, it is excellent in solvent solubility and compatibility with the thermosetting resin component to be blended. Moreover, since a uniform rough surface can be formed with low roughness, the fine wiring formability is excellent.

  The phenoxy resin having a bisphenol acetophenone structure can be synthesized by a known method such as a method in which an epoxy resin and a phenol resin are polymerized with a catalyst.

  The phenoxy resin having a bisphenol acetophenone structure may contain a structure other than the bisphenol acetophenone structure of the general formula (X), and the structure is not particularly limited, but bisphenol A type, bisphenol F type, bisphenol S type, biphenyl Type, phenol novolac type, cresol novolac type structure and the like. Among them, those containing a biphenyl structure are preferable because of their high glass transition temperature.

  The content of the bisphenol acetophenone structure of the general formula (X) in the phenoxy resin containing a bisphenol acetophenone structure is not particularly limited, but is preferably 5 mol% to 95 mol%, more preferably 10 mol% to 85 mol%. More preferably, it is 15 mol% or more and 75 mol% or less. If the content is less than the lower limit, the effect of improving heat resistance and moisture resistance reliability may not be obtained. Moreover, since solvent solubility will worsen when content exceeds an upper limit, it is unpreferable.

  The weight average molecular weight (Mw) of the phenoxy resin is not particularly limited, but is preferably from 5,000 to 100,000, more preferably from 10,000 to 70,000, and most preferably from 20,000 to 50,000. . When Mw exceeds the upper limit, the compatibility with other resins and the solubility in a solvent are extremely poor, which is not preferable. When the Mw is less than the lower limit, the film-forming property is deteriorated and used for manufacturing a circuit board. In addition, it is not preferable because it causes a problem.

  The content of the phenoxy resin is not particularly limited, but is preferably 5% by weight or more and 40% by weight or less, and particularly preferably 10% by weight or more and 20% by weight or less of the resin composition excluding the filler. If the content is less than the above lower limit value, the mechanical strength of the insulating resin layer may decrease or the plating adhesion with the conductor circuit may decrease. If the content exceeds the above upper limit value, the thermal expansion coefficient of the insulating resin layer may decrease. May increase and heat resistance may decrease.

  Further, the resin composition may contain additives other than the above components such as pigments, dyes, antifoaming agents, leveling agents, ultraviolet absorbers, foaming agents, antioxidants, flame retardants, and ion scavengers as necessary. It may be added.

  Examples of pigments include kaolin, synthetic iron oxide red, cadmium yellow, nickel titanium yellow, strontium yellow, hydrous chromium oxide, chromium oxide, cobalt aluminate, synthetic ultramarine blue and other inorganic pigments, phthalocyanine polycyclic pigments, azo pigments, etc. Etc.

  Examples of the dye include isoindolinone, isoindoline, quinophthalone, xanthene, diketopyrrolopyrrole, perylene, perinone, anthraquinone, indigoid, oxazine, quinacridone, benzimidazolone, violanthrone, phthalocyanine, and azomethine.

  Subsequently, the element mounting substrate 108 shown in FIG. 1B is obtained by molding the prepreg 107 obtained in FIG. 1A by heating and pressing. The element mounting substrate 108 can be a substrate constituted by a single core material or a substrate in which another resin layer is laminated on the core material.

  Although it does not specifically limit as said heat-processing method, For example, it can implement using a hot-air drying apparatus, an infrared heating apparatus, a heating roll apparatus, a flat platen hot-plate press apparatus, etc. When a hot-air drying device or an infrared heating device is used, the bonding can be carried out without substantially applying pressure to the joined ones. Moreover, when using a heating roll apparatus or a flat hot platen press apparatus, it can implement by making predetermined | prescribed pressure act on the said joined thing.

  In the preparation step, it is preferable to prepare the element mounting substrate that warps on the side opposite to the element mounting surface at a temperature higher than room temperature. For example, the temperature at which the heat treatment is performed is not particularly limited, but is preferably a temperature range in which the resin used is melted and the resin curing reaction does not proceed rapidly. For example, the heating temperature is preferably 120 ° C. or higher and 250 ° C. or lower, and more preferably 150 ° C. or higher and 230 ° C. or lower.

In addition, since the time for the heat treatment varies depending on the type of resin used and the like, it is not particularly limited. For example, the heat treatment can be performed by treating for 30 minutes or more and 180 minutes or less.
Moreover, the pressure to pressurize is not particularly limited, but is preferably 0.2 MPa or more and 5 MPa or less, and more preferably 2 MPa or more and 4 MPa or less.

(Element mounting board with metal foil)
Next, the element mounting substrate with metal foil will be described.
The element mounting substrate 108 according to the present embodiment is not shown, but may be an element mounting substrate with a metal foil in which a metal foil is formed on at least one side. For example, a metal stay can be formed on the element mounting surface 110 side.
The thickness of the metal foil is preferably 1 μm or more and 18 μm or less. More preferably, they are 2 micrometers or more and 12 micrometers or less. When the thickness of the metal foil is within the above range, a fine pattern can be formed, and the element mounting substrate can be thinned.

  Examples of the metal constituting the metal foil include copper and copper alloys, aluminum and aluminum alloys, silver and silver alloys, gold and gold alloys, zinc and zinc alloys, nickel and nickel alloys, tin and tin alloys. Alloys, iron and iron-based alloys, Kovar (trade name), 42 alloys, Fe-Ni alloys such as Invar or Super Invar, W or Mo, and the like can be given. Also, an electrolytic copper foil with a carrier can be used.

  Further, a film may be laminated on at least one surface of the element mounting substrate 108 instead of the metal foil. Examples of the film include polyethylene, polypropylene, polyethylene terephthalate, polyethylene naphthalate, polyimide, and fluorine resin.

  As a manufacturing method of the element mounting board | substrate with metal foil, it is as follows, for example. In the case of an element mounting substrate obtained by laminating two prepregs, metal foil is stacked on the upper and lower surfaces or one side of the outer sides of the laminated first prepreg and second prepreg, and high vacuum conditions are used using a laminator device or a becquerel device. These are joined below, or metal foil is overlapped on the upper and lower surfaces or one surface outside the first prepreg and the second prepreg as they are. Next, an element mounting substrate can be obtained by heating and pressurizing a laminate of a prepreg and a metal foil with a vacuum press or by heating with a dryer.

(Element mounting substrate with wiring layer 108)
Next, a process of forming a wiring layer on the element mounting substrate with metal foil 108 will be described. For example, a through hole for interlayer connection is formed in the element mounting substrate 108 with metal foil. Subsequently, a subtractive construction method, a semi-additive construction method, etc. are given and a wiring layer is produced. In the drawing, the through hole and the wiring layer are not shown.

In addition, after that, an arbitrary buildup layer may be laminated, and the step of interlayer connection and circuit formation by an additive method may be repeated to form a circuit layer. Here, some or all of the buildup layers may or may not include a fiber base layer.
A build-up layer and a solder resist layer may be formed on the circuit layer.

  As described above, it is possible to obtain the element mounting substrate 108 in which a smile type warp has occurred.

(Mounting process)
Next, the mounting process of this embodiment will be described.
FIG. 3 is a process top view of the mounting process. FIG. 2A is a cross-sectional view taken along the line AA ′ of FIG.
As shown in FIG. 3, a plurality of semiconductor chips 116 are arranged on the element mounting surface 110 of the element mounting substrate 108. On the element mounting surface 110, a package area 114 partitioned by a dicing region 112 is formed. The package area 114 is arranged at a predetermined interval. One semiconductor chip 116 may be formed in one package area 114, or a plurality of semiconductor chips 116 may be formed. In this embodiment, an example in which one semiconductor chip 116 is arranged in one package area 114 will be described. The outer edge of the semiconductor chip 116 corresponds to the outer edge of the package area 114.

  In the present embodiment, the distance between the center package areas 114 that are closest to the center position is L1, and the distance between the center package area 114 and the outer package area 114 disposed outside the center package area 114 is L2. L2 may be the same as L1, or may be larger than L1. By setting L2 = L1, the semiconductor chips 116 can be arranged with high density. Further, by setting L2> L1, the difference between the linear expansion coefficient of the element mounting surface 110 and the linear expansion coefficient on the opposite surface side can be reduced outside the element mounting substrate 108. Thereby, the curvature of the outside of the element mounting substrate 108 can be reduced.

  As shown in FIG. 2A, the element mounting substrate 108 and the semiconductor chip 116 are electrically connected through, for example, solder bumps 118 and a wiring layer (not shown). In addition, the electrode of the element mounting substrate 108 and the semiconductor chip 116 may be connected by a bonding wire.

The element mounting substrate 108 and the semiconductor chip 116 are connected as follows, for example.
First, after temporarily fixing the semiconductor chip 116 to the element mounting substrate 108 with an adhesive, these are thermocompression bonded. In the present embodiment, the adhesive may be liquid or sheet-like. The adhesive may have a flux activator.
Next, the semiconductor chip 116 and the element mounting substrate 108 are solder-bonded by heating the laminated body including the semiconductor chip 116 and the element mounting substrate 108 at a temperature equal to or higher than the melting point of the solder bump 118. Thereby, the semiconductor chip 116 and the element mounting substrate 108 are connected to each other.

  The semiconductor chip 116 is not particularly limited, but preferably has a chip size package structure, for example.

(Molding process)
Then, the molding process of this Embodiment is demonstrated.
As shown in FIG. 2B, the semiconductor chip 116 on the element mounting substrate 108 is simultaneously molded with a sealing material. The entire semiconductor chip 116 is covered with a mold resin layer 120. Thereby, a semiconductor package is formed. In the semiconductor package, the gap between the semiconductor chips 116 is embedded with a mold resin layer 120.

  In the molding step, the mold resin layer 120 is further formed on the element mounting substrate 108 on which the semiconductor chip 116 is mounted, thereby reducing the cry-shaped warpage of the element mounting substrate 108 that has occurred during mounting. Become.

Although the dimension of a semiconductor package is not specifically limited, It is preferable to satisfy | fill all of the following conditions (1)-(3).
(1) The chip height (thickness H1) is preferably 50 μm or more and 100 μm or less, and more preferably 60 μm or more and 90 μm or less.
(2) The thickness H2 of the sealing material is preferably 100 μm or more and 500 μm or less, and more preferably 150 μm or more and 300 μm or less.
(3) The thickness H3 of the element mounting substrate is preferably 50 μm or more and 300 μm or less, and more preferably 100 μm or more and 200 μm or less.
The thickness H1 to the thickness H3 may be an average thickness, for example.
When the dimensions of the semiconductor package satisfy all of the above conditions (1) to (3), it is possible to reduce warpage in the thin semiconductor package. That is, when the element mounting substrate 108 and the mold resin layer 120 are thin layers, the remaining warpage at the time of mounting is likely to occur in the semiconductor package. On the other hand, in the present embodiment, even in such a thin semiconductor package, it is possible to reduce the remaining warp during mounting.

In the preparation process, the mounting process, and the molding process of the present embodiment, it is preferable to satisfy the following average value of package warpage.
That is, the average value of the amount of package warpage in each process is
It is preferable that 0 <p, 0> q, | r | <| p |, | r | <| q |
However, using a temperature variable laser three-dimensional measuring machine (LS200-MT100MT50: manufactured by TETECH Co., Ltd.), measurement is performed by applying a laser to the surface opposite to the semiconductor element mounting surface with respect to the package area at room temperature. The difference between the farthest point farthest from the laser head and the closest point from the laser head is defined as the amount of package warpage.
Further, in the preparation step, p is an average value of the amount of package warpage of each package area,
In the mounting process, the average value of the amount of package warpage in each package area is q,
Let r be the average value of the amount of package warpage in each package area in the molding step.

  In the present embodiment, an asymmetric prepreg is used, and the average value of the amount of package warpage in the package area in each process satisfies the above conditions, so that a smile-type warp is generated in the preparation process and the mounting process is performed. As a result, it is possible to reduce the warpage of the cry mold and further reduce the residual cry warpage generated in the mounting process in the molding process.

In addition, the average value p of the amount of package warpage in each package area in the preparation step is not particularly limited as long as it is larger than 0. For example, it is preferably 200 μm or less, and more preferably 100 μm or less. In addition, it is not particularly limited as long as q is smaller than 0, but it is preferably −300 μm or more, more preferably −290 μm or more.
When the average values p and q satisfy the above conditions, it is possible to sufficiently reduce the remaining warp during mounting in the semiconductor package.

  Here, in the present embodiment, the amount of warp of the smile type warp is a positive value, and the amount of warp of the cry type warp is a negative value. That is, when the upper edge portion of the element mounting substrate is located above the center position of the element mounting surface 110, the warpage amount is a positive value. On the other hand, when the upper edge portion of the element mounting substrate is located below the center position of the element mounting surface 110, the warpage amount is a negative value.

The sealing material constituting the mold resin layer 120 is constituted by a cured product of a resin composition including, for example, an epoxy resin, a phenol resin curing agent, a curing accelerator, an inorganic filler, and the like.
The thermal expansion coefficient of the sealing material at normal temperature is preferably 9 ppm / ° C. or more and 50 ppm / ° C. or less. The molding shrinkage of the sealing material is preferably 0.05% to 0.8%, and more preferably 0.2% to 0.75%. Thereby, the curvature of the semiconductor package in normal temperature can be reduced more.
The sealing material has, for example, a biphenyl type epoxy resin (manufactured by Japan Epoxy Resin, “model number: YX-4000”, melting point: 105 ° C., epoxy equivalent: 190) as an epoxy resin, and a biphenylene skeleton as a curing agent. Phenol aralkyl resin (Maywa Kasei Co., Ltd., “Model No .: MEH-7851SS”, softening point: 65 ° C., hydroxyl equivalent: 203), and phenol novolac resin (Sumitomo Bakelite, PR 51470, softening point: 110 ° C., hydroxyl equivalent: 104) After blending spherical fused silica (average particle size: 12.5 μm) as an inorganic filler and kneading / defoaming using three rolls, a biaxial roll having surface temperatures of 95 ° C. and 25 ° C. And kneaded 20 times, and the obtained kneaded material sheet can be obtained by cooling and pulverizing.

(Separation process)
Subsequently, as shown in FIG. 4A, solder bumps 128 are formed on the opposite surface side of the element mounting substrate 108. Thereafter, as shown in FIG. 4B, the semiconductor chip 116 is separated into pieces by using a dicing saw 130 or the like. For example, dicing is performed along the dicing region 112 shown in FIG. 3 to divide each molded semiconductor chip 116 into individual pieces. Thereby, the semiconductor device 100 can be obtained.
Note that an electronic device can be obtained by mounting the semiconductor device 100 on a motherboard or the like.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail with reference to an Example, this invention is not limited to description of these Examples at all. Unless otherwise specified, “parts” described below indicates “parts by weight” and “%” indicates “% by weight”.

1. Preparation of varnish of thermosetting resin composition 11.0 parts by weight of biphenylaralkyl type novolak epoxy resin (manufactured by Nippon Kayaku Co., Ltd., NC-3000) as an epoxy resin, biphenyldimethylene type phenol resin (Nippon Kayaku Co., Ltd.) as a curing agent Company company, GPH-103) 8.8 parts by weight and novolac-type cyanate resin (Lonza Japan KK, Primaset PT-30) 20.0 parts by weight were dissolved and dispersed in methyl ethyl ketone. Furthermore, 60.0 parts by weight of spherical fused silica (manufactured by Admatechs, “SO-25R”, average particle size 0.5 μm) as an inorganic filler and a coupling agent (Momentive Performance Materials Japan, A -187) 0.2 parts by weight were added. This was stirred for 30 minutes using a high-speed stirrer and adjusted so as to have a nonvolatile content of 50% by weight to prepare a varnish (resin varnish) of a thermosetting resin composition.

2. Production of carrier material and production of prepreg (Example 1)
The resin varnish is coated on a PET film (polyethylene terephthalate, Teijin DuPont Films PUREX film, thickness 36 μm) using a die coater so that the thickness of the resin layer after drying is 22.0 μm. Worked. This was dried for 5 minutes with a 160 degreeC drying apparatus, and the resin sheet with a PET film for 1st resin layers was obtained.
The resin varnish was coated on a PET film in the same manner as described above so that the thickness of the resin layer after drying was 15.0 μm. This was dried with a dryer at 160 ° C. for 5 minutes to obtain a resin sheet with a PET film for the second resin layer.

The resin sheet with a PET film for the first resin layer and the resin sheet with a PET film for the second resin layer are placed on both sides of a glass fiber substrate (thickness 46 μm, manufactured by Nittobo, WEA-1280, IPC standard 1280). The resin layer is placed so as to face the fiber base material, and heated and pressurized by a vacuum press at a pressure of 0.5 MPa and a temperature of 140 ° C. for 1 minute to impregnate the thermosetting resin composition, and a carrier film is laminated. A prepreg (1) was obtained. At this time, the thickness (d1) of the first resin layer is 10 μm, the thickness of the fiber base layer is 46 μm, the thickness (d2) of the second resin layer is 4 μm, the total thickness is 60 μm, and d1 / d2 is 2.5. Met.
In addition, d1 and d2 are measured as follows, for example. First, a 12 μm copper foil (3EC-VLP foil manufactured by Mitsui Mining & Smelting Co., Ltd.) is superposed on both sides of the prepreg, and heat-pressed at 220 ° C. and 3 MPa for 2 hours to obtain a metal-clad laminate. Next, the cut surface of the metal-clad laminate is polished, and the glass fiber substrate and the resin surface are measured using a laser microscope. The shortest distance at this time is d1 or d2.

(Example 2)
In Example 2, a resin sheet with a PET film for a first resin layer having a resin thickness of 35.0 μm, a resin sheet with a PET film for a second resin layer having a resin thickness of 25.0 μm, and a glass fiber substrate (thickness of 80 μm) Unite glass fiber, E09B 04 53SK, IPC standard 2319) was prepared. Using these, the thickness (d1) of the first resin layer is 15 μm, the thickness of the fiber base layer is 80 μm, the thickness (d2) of the second resin layer is 5 μm, the total thickness is 100 μm, and d1 / d2 is A prepreg (2) of 3 was obtained.

(Example 3)
In Example 3, a resin sheet with a PET film for a first resin layer having a resin thickness of 32.0 μm, a resin sheet with a PET film for a second resin layer having a resin thickness of 28.0 μm, and a glass fiber substrate (thickness of 80 μm) ) Was prepared. Using these, the thickness (d1) of the first resin layer is 12 μm, the thickness of the fiber base layer is 80 μm, the thickness (d2) of the second resin layer is 8 μm, the total thickness is 100 μm, and d1 / d2 is A prepreg (3) of 1.5 was obtained.

(Example 4 and Example 5)
In Example 4 and Example 5, a resin sheet with a PET film for a first resin layer having a resin thickness of 16.0 μm, a resin sheet with a PET film for a second resin layer having a resin thickness of 10.0 μm, and a glass fiber substrate (Thickness 28 μm) was prepared. Using these, the thickness (d1) of the first resin layer is 9 μm, the thickness of the fiber base layer is 28 μm, the thickness (d2) of the second resin layer is 3 μm, the total thickness is 40 μm, and d1 / d2 is A prepreg (4) of 3 was obtained.

(Comparative Example 1)
In Comparative Example 1, the resin varnish was impregnated into a glass fiber substrate (thickness 46 μm, manufactured by Nittobo, WEA-1280, IPC standard 1280), dried in a heating furnace at 150 ° C. for 2 minutes, and prepreg (5) Got. At this time, the thickness of the fiber base layer was 46 μm, the resin layers having the same thickness (7 μm) were provided on both surfaces of the fiber base layer, and the total thickness was 60 μm.

(Comparative Example 2)
In Comparative Example 2, the resin varnish was impregnated into a glass fiber substrate (thickness 80 μm, manufactured by Unitika Glass Fiber Co., Ltd., E09B 04 53SK, IPC standard 2319), dried in a heating furnace at 150 ° C. for 2 minutes, and prepreg (6) was obtained. At this time, the thickness of the fiber base layer was 80 μm, the resin layers having the same thickness (10 μm) were provided on both surfaces of the fiber base layer, and the total thickness was 100 μm.

3. Production of metal-clad laminate (Example 1)
A metal-clad laminate was obtained by overlaying 12 μm copper foil (3EC-VLP foil manufactured by Mitsui Mining & Smelting Co., Ltd.) on both sides of the prepreg (1) and heating and pressing at 220 ° C. and 3 MPa for 2 hours. The thickness of the core layer (part consisting of an insulating substrate) of the obtained metal-clad laminate was 0.06 mm.

(Example 2)
A 12 μm copper foil was superposed on both sides of the prepreg (2), and was heated and pressed in the same manner as in Example 1.

(Example 3)
A 12 μm copper foil was superposed on both sides of the prepreg (3), and was heated and pressed in the same manner as in Example 1.

Example 4
Two prepregs (4) were laminated, and 12 μm copper foil was superimposed on both sides, and heat-press molding was performed in the same manner as in Example 1.

(Example 5)
Three prepregs (4) were laminated, and a 12 μm copper foil was laminated on both sides, and heat-press molding was performed in the same manner as in Example 1.

(Comparative Example 1)
A 12 μm copper foil was superposed on both sides of the prepreg (5) and heat-pressed in the same manner as in Example 1.

(Comparative Example 2)
A 12 μm copper foil was superposed on both sides of the prepreg (6), and was heated and pressed in the same manner as in Example 1.

4). Production of Printed Wiring Board Using the obtained metal-clad laminate as a core substrate, circuit patterns were formed on both surfaces thereof (remaining copper ratio 70%, L / S = 50/50 μm) to obtain an inner layer circuit board. Next, on the front and back of the inner layer circuit board, a commercially available prepreg (manufactured by Sumitomo Bakelite Co., Ltd., 6785GS-F, thickness 50 μm) is overlaid, and further 12 μm copper foil is overlaid on top and bottom, pressure 3 MPa, temperature 220 Heat-press molding was carried out at 2 ° C. for 2 hours.
The copper foil was removed from the printed wiring board thus obtained by etching. Next, blind via holes (non-through holes) were formed in the printed wiring board by a carbonic acid laser. Next, the printed wiring board is immersed in a swelling solution at 60 ° C. (Atotech Japan Co., Ltd., Swelling Dip Securigant P) for 5 minutes, and further an aqueous potassium permanganate solution at 80 ° C. (Atotech Japan Co., Ltd., After soaking in Concentrate Compact CP) for 10 minutes, the surface of the via and the surface of the resin layer were roughened by neutralization.
Next, after passing through the steps of degreasing, catalyst application, and activation, an electroless copper plating film and a plating resist of about 0.5 μm were formed. Next, after forming a 10 μm patterned electroplated copper using the electroless copper plating film as a power feeding layer, fine circuit processing of L / S = 50/50 μm was performed. Next, an annealing process was performed at 200 ° C. for 60 minutes using a hot air drying apparatus, and then the power feeding layer was removed by flash etching. Thereby, a four-layer printed wiring board was manufactured.
Next, a solder resist (manufactured by Taiyo Ink Manufacturing Co., Ltd., PSR-4000 AUS703) was printed on the four-layer printed wiring board. Next, the solder resist layer was exposed, developed, and cured using a predetermined mask so that the semiconductor element mounting pad and the like were exposed. At this time, the solder resist layer was formed so that the thickness of the solder resist layer on the circuit was 12 μm.
Next, a plating layer was formed on the circuit layer exposed from the solder resist layer. The plating layer is composed of an electroless nickel plating layer of 3 μm provided on the circuit layer and an electroless gold plating layer of 0.1 μm provided thereon. The substrate thus obtained was cut to obtain a printed wiring board for a semiconductor device.

5. Manufacturing of Semiconductor Device A semiconductor element (TEG chip, size 10 mm × 10 mm, thickness 100 μm) having solder bumps was mounted on the printed wiring board for the semiconductor device by thermocompression bonding using a flip chip bonder device. At this time, the semiconductor element was mounted so that the first resin layer of the prepreg used for the core substrate was on the semiconductor element mounting surface side. Next, the solder bumps were melted in an IR reflow furnace to join the semiconductor element and the printed wiring board. Next, a liquid sealing resin (manufactured by Sumitomo Bakelite Co., Ltd., CRP-4160A3) was filled, and the liquid sealing resin was cured. The liquid sealing resin was cured at a temperature of 150 ° C. for 120 minutes. The solder bumps of the semiconductor element used were formed with Sn / Ag composition.
Next, an epoxy sealing material (manufactured by Sumitomo Bakelite Co., Ltd., silica filling amount of 75 wt%) was molded using a compression molding machine. Then, the semiconductor device was obtained by dicing to 14 mm x 14 mm size.

(Evaluation of semiconductor devices)
1. Measurement of warpage amount The warpage amount of the element mounting substrate was measured in the preparation step, the mounting step, and the molding step prepared in the examples and comparative examples. Thereby, the warpage amount of the semiconductor device was evaluated.
In each of the examples and comparative examples, the warpage of each of the six package areas was measured for each step, and the average value thereof was listed in Table 1 as the amount of warpage of the element mounting substrate in each step.
The amount of warpage of each package area was measured at room temperature using a temperature variable laser three-dimensional measuring machine (LS200-MT100MT50: manufactured by Teatech Co., Ltd.). The measurement range was 13 mm × 13 mm, and the measurement was performed by applying a laser to the BGA surface opposite to the semiconductor element mounting surface. At this time, the difference between the farthest point farthest from the laser head and the nearest point closest to the laser head was taken as the amount of warpage.
Here, the amount of warp of the smile type warp is a positive value, and the amount of warp of the cry type warp is a negative value. That is, when the edge of the element mounting surface is located above the center position of the element mounting surface, the amount of warpage becomes a positive value. In addition, when the edge of the element mounting surface is positioned below the center position of the element mounting surface, the warpage amount is a negative value. Here, the element mounting surface side is defined as the upper side, and the surface side opposite to the element mounting surface is defined as the lower side.

2. Temperature Cycle (TC) Test For the semiconductor devices obtained in the examples and comparative examples, the temperature was set to −65 ° C. for 15 minutes in the air, and then set to −150 ° C. for 15 minutes, or 150 ° C. for 15 minutes. Then, it was set as -65 degreeC for 15 minutes as 1 cycle, and the conduction | electrical_connection after 2000 cycle processing was evaluated. A continuity test was conducted on the circuit terminals that returned from the printed wiring board to the printed wiring board through the semiconductor elements via solder bumps, and the disconnected portions were examined. Each code is as follows.
(Double-circle): There was no disconnection location.
○: The disconnection portion was 1 to 10%.
(Triangle | delta): The disconnection location was 11 to 50%.
X: The disconnection location was 51% or more.

In each of Examples 1 to 5, the absolute value of the warpage amount after the molding process was 100 or less. For this reason, in Examples 1-5, it became clear that the curvature amount of the semiconductor device manufactured can be reduced.
Moreover, in Examples 1-5, all had no disconnection location after the temperature cycle test. On the other hand, in Comparative Examples 1 and 2, a broken portion occurred after the temperature cycle test.

  Needless to say, the above-described embodiment and a plurality of modifications can be combined within a range in which the contents do not conflict with each other. Further, in the above-described embodiments and modifications, the structure of each part has been specifically described, but the structure and the like can be changed in various ways within a range that satisfies the present invention.

5a Carrier material 5b Carrier material 11 Fiber substrate 21 Prepreg 60 Vacuum laminating device 61 Laminating roll 62 Hot air drying device 100 Semiconductor device 102 Fiber substrate layer 102a First fiber substrate layer 102b Second fiber substrate layer 102c Intermediate fiber substrate Layer 104 first resin layer 106 second resin layer 107 prepreg 108 element mounting substrate 110 element mounting surface 112 dicing area 114 package area 116 semiconductor chip 118 solder bump 120 mold resin layer 122 intermediate resin layer 124 intermediate resin layer 126 intermediate resin layer 128 Solder bump 130 dicing saw

Claims (9)

Preparing a device mounting substrate having a plurality of package areas partitioned by a dicing region; and
A mounting step of mounting a semiconductor chip in each of the package areas of the element mounting substrate;
A molding step of simultaneously molding the semiconductor chip with a sealing material;
Dividing along the dicing region, and a singulation step of dividing each molded semiconductor chip,
Including
The element mounting substrate includes a fiber base layer obtained by impregnating a fiber base with a resin, a first resin layer formed on the element mounting surface side of the fiber base layer, and the other of the fiber base layers. Including a core material composed of a second resin layer formed on the surface side,
A method for manufacturing a semiconductor device, wherein the thickness of the first resin layer is larger than the thickness of the second resin layer. A method of manufacturing a semiconductor device according to claim 1,
The element mounting substrate is a substrate constituted by the core material alone, or a substrate in which another resin layer is laminated on the core material,
The distance from the element mounting surface of the element mounting substrate to one surface of the fiber base layer is d1,
When the distance from the surface opposite to the element mounting surface of the element mounting substrate to the other surface of the fiber base layer is d2,
A method for manufacturing a semiconductor device, wherein d1> d2. A method of manufacturing a semiconductor device according to claim 2,
A method for manufacturing a semiconductor device, wherein d1 / d2 is 1.5 or more. A method for manufacturing a semiconductor device according to any one of claims 1 to 3,
A method of manufacturing a semiconductor device, wherein the semiconductor device has a chip size package structure. A method for manufacturing a semiconductor device according to any one of claims 1 to 4,
The said sealing material is a manufacturing method of a semiconductor device containing 50 weight% or more of inorganic fillers on the basis of the whole sealing material. A method of manufacturing a semiconductor device according to any one of claims 1 to 5,
The said semiconductor device is a manufacturing method of the semiconductor device which has the following external dimensions.
(1) The chip height is 50 μm or more and 100 μm or less,
(2) The thickness of the sealing material is 100 μm or more and 500 μm or less,
(3) The thickness of the element mounting substrate is 50 μm or more and 300 μm or less. A method of manufacturing a semiconductor device according to any one of claims 1 to 6,
The preparation step includes a step of preparing the element mounting substrate that warps opposite to the element mounting surface side at a temperature higher than room temperature. A method for manufacturing a semiconductor device according to any one of claims 1 to 7,
The farthest point from the laser head when the laser is applied to the surface opposite to the device mounting surface with respect to the package area at room temperature using a variable temperature laser CMM. And the difference between the closest point from the laser head and the closest point is defined as the amount of package warp,
In the preparation step, p is an average value of the amount of package warpage of each package area,
In the mounting process, the average value of the amount of package warpage in each package area is q,
When the average value of the amount of package warpage of each package area in the molding process is r,
0 <p, 0> q, | r | <| p |, | r | <| q |
The manufacturing method of the semiconductor device which satisfy | fills. A method for manufacturing a semiconductor device according to claim 8, comprising:
p is greater than 0 and less than or equal to 200 μm;
A method of manufacturing a semiconductor device, wherein q is −300 μm or more and less than 0.

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