JP2023149598A - Sealing resin composition, and manufacturing method of semiconductor package - Google Patents

Abstract

[Problem] To provide an encapsulant whose surface is uniformly polished when the encapsulant is formed on a base material, and further to accurately form wiring formed on the encapsulant in a subsequent process. The present invention provides a sealing resin composition that has an excellent yield of semiconductor package products. [Solution] The sealing resin composition of the present invention is used for a wafer level package, and includes (A) an epoxy resin, (B) an inorganic filler, and (C) a carboxylic acid dispersant, and includes the following: The amount of warpage of the cured product of the sealing resin composition measured under the following conditions is 1.1 mm or less. (Conditions) Using a compression molding machine, the sealing resin composition was compression molded at 150°C for 300 seconds on a silicon wafer with a thickness of 775 μm and a diameter of 12 inches, and then Post Mold at 150°C for 4 hours. Cure (PMC) is performed to obtain a 500 μm thick cured product of the sealing resin composition. Place the silicon wafer with the obtained cured product so that the silicon wafer surface is in contact with a horizontal precision stone surface plate, and measure the height from the precision stone surface plate to the silicon wafer at 8 points that divide the outer periphery into 8 equal parts. The average value of the heights of the eight points is defined as the wafer warpage amount [mm]. [Selection diagram] None

Description

The present invention relates to a sealing resin composition used in a wafer level package and a method for manufacturing a semiconductor package.

Various techniques have been developed for sealing resin compositions.
For example, Patent Document 1 discloses a sealing resin composition containing an epoxy resin, a curing agent, a filler, a predetermined amount of a silane coupling agent, and a predetermined amount of a low stress agent. . This document states that this sealing resin composition can reduce warping of a base material in an electronic device and exhibit a good balance of adhesion and filling properties.

Further, Patent Document 2 discloses a sealing resin composition containing an epoxy resin, a compound having a polyalkylene glycol chain made of a predetermined compound, and an inorganic filler. The document describes that according to this resin composition for sealing, warpage can be suppressed even when a large-area substrate is sealed.

Japanese Patent Application Publication No. 2018-188494 International Publication No. 2019/146617

However, when the encapsulating resin compositions described in Patent Documents 1 and 2 are used as a encapsulating material for a wafer level package, polishing of the encapsulating material becomes uneven, and furthermore, in the subsequent rewiring process. In some cases, the yield of semiconductor devices is lowered, such as because the wiring cannot be formed accurately. Further, when the encapsulating resin composition is used in a method for manufacturing a semiconductor package, the base material is insufficiently fixed in the polishing process of the encapsulating material, and there is room for improvement in manufacturing stability.

The present inventors have discovered that the above-mentioned problem can be solved by using a sealing resin composition having a predetermined composition and in which the amount of warpage of the cured product of the composition is equal to or less than a predetermined value, and has completed the present invention. I let it happen.
That is, the present invention can be shown below.

According to the invention,
A sealing resin composition used for a wafer level package, comprising:
(A) an epoxy resin;
(B) an inorganic filler;
(C) a carboxylic acid dispersant;
It is possible to provide a sealing resin composition in which the amount of warpage of a cured product of the sealing resin composition measured under the following conditions is 1.1 mm or less.
(conditions)
Using a compression molding machine, the sealing resin composition was compression molded at 150°C for 300 seconds on a silicon wafer with a thickness of 775 μm and a diameter of 12 inches, and then Post Mold Cure (PMC) was performed at 150°C for 4 hours. ) to obtain a 500 μm thick cured product of the sealing resin composition. Place the silicon wafer with the obtained cured product so that the silicon wafer surface is in contact with a horizontal precision stone surface plate, and measure the height from the precision stone surface plate to the silicon wafer at 8 points that divide the outer periphery into 8 equal parts. The average value of the heights of the eight points is defined as the wafer warpage amount [mm].

According to the invention,
a step of arranging a plurality of semiconductor chips on a base material;
a step of sealing the semiconductor chip with a cured product of the sealing resin composition on the base material on which the semiconductor chip is disposed;
a step of singulating the semiconductor chip;
A method of manufacturing a semiconductor package is provided.

The encapsulating resin composition of the present invention can provide a encapsulating material whose surface is uniformly polished when the encapsulating material is formed on a base material, and can further improve wiring formed in subsequent steps. Since it can be formed accurately on the encapsulant, the yield of semiconductor package products is excellent. Further, according to the present invention, the encapsulant can be uniformly polished in the encapsulant polishing step, and a method for manufacturing a semiconductor package with excellent production stability can be provided.

FIG. 2 is a cross-sectional view showing an example of a method for manufacturing a semiconductor package according to the present embodiment.

Embodiments of the present invention will be described below with reference to the drawings. Note that in all the drawings, similar components are denoted by the same reference numerals, and descriptions thereof will be omitted as appropriate. Further, for example, "1 to 10" represents "1 or more" to "10 or less" unless otherwise specified.

The encapsulating resin composition of this embodiment is a encapsulating resin composition used for a wafer level package, and includes:
(A) an epoxy resin;
(B) an inorganic filler;
(C) a carboxylic acid dispersant;
The amount of warpage of the cured product of the sealing resin composition measured under the following conditions is 1.1 mm or less, preferably 1.0 mm or less, and more preferably 0.7 mm or less.
(conditions)
Using a compression molding machine, the sealing resin composition was compression molded at 150°C for 300 seconds on a silicon wafer with a thickness of 775 μm and a diameter of 12 inches, and then Post Mold Cure (PMC) was performed at 150°C for 4 hours. ) to obtain a 500 μm thick cured product of the sealing resin composition. Place the silicon wafer with the obtained cured product so that the silicon wafer surface is in contact with a horizontal precision stone surface plate, and measure the height from the precision stone surface plate to the silicon wafer at 8 points that divide the outer periphery into 8 equal parts. The average value of the heights of the eight points is defined as the wafer warpage amount [mm].

The sealing resin composition of this embodiment has a predetermined composition, and the amount of warpage of the cured product of the composition is less than or equal to a predetermined value, so that when a sealant is formed on a base material, the surface It is possible to provide an encapsulant that is uniformly polished, and furthermore, wiring to be formed in subsequent steps can be accurately formed on the encapsulant, resulting in an excellent yield of semiconductor package products.
The amount of warpage of the cured product can be set within the above range by adjusting the components, contents, etc. contained in the sealing resin composition of the present embodiment.

[Epoxy resin (A)]
The epoxy resin (A) is a compound having two or more epoxy groups in one molecule, and may be a monomer, an oligomer, or a polymer.

Specifically, the epoxy resin (A) includes crystalline epoxy resins such as biphenyl-type epoxy resins, bisphenol-type epoxy resins, and stilbene-type epoxy resins; novolac-type epoxy resins such as phenol novolac-type epoxy resins and cresol novolac-type epoxy resins. ; Multifunctional epoxy resins such as trisphenylmethane type epoxy resins and alkyl-modified triphenolmethane type epoxy resins; Phenol aralkyl type epoxy resins such as phenylene skeleton-containing phenol aralkyl type epoxy resins and biphenylene skeleton containing phenol aralkyl type epoxy resins; Dihydroxynaphthalene naphthol type epoxy resins, such as epoxy resins obtained by glycidyl etherification of dihydroxynaphthalene dimers; triazine nucleus-containing epoxy resins such as triglycidyl isocyanurate and monoallyl diglycidyl isocyanurate; dicyclopentadiene-modified phenols One or more types selected from the group consisting of bridged cyclic hydrocarbon compound-modified phenol type epoxy resins such as type epoxy resins.

From the viewpoint of the effects of the present invention, the epoxy resin (A) is preferably a trisphenylmethane type epoxy resin, a biphenylaralkyl type polyfunctional epoxy resin, an orthocresol type bifunctional epoxy resin, a biphenyl type bifunctional epoxy resin, or a bisphenol type epoxy resin. One or more types selected from the group consisting of bifunctional epoxy resins and dicyclopentadiene type bifunctional epoxy resins. The epoxy resin (A) is more preferably a biphenylaralkyl type polyfunctional epoxy resin or a dicyclopentadiene type bifunctional epoxy resin.

The content of the epoxy resin (A) in the sealing resin composition is determined from the viewpoint of obtaining suitable fluidity during molding to improve fillability and moldability, and from the viewpoint of improving the reliability of the resulting device. Based on the entire sealing resin composition, preferably 0.5% by mass or more and 20% by mass or less, more preferably 1% by mass or more and 15% by mass or less, and even more preferably 2% by mass or more and 10% by mass or less. be.

[Inorganic filler (B)]
As the inorganic filler (B), those commonly used in resin compositions for semiconductor encapsulation can be used. Moreover, the inorganic filler (B) may be surface-treated.

Specific examples of the inorganic filler (B) include silica such as fused silica, crystalline silica, and amorphous silicon dioxide; alumina; talc; titanium oxide; silicon nitride; and aluminum nitride. These inorganic fillers may be used alone or in combination of two or more.

The inorganic filler (B) preferably contains silica from the viewpoint of excellent versatility. Examples of the shape of silica include spherical silica and crushed silica.

The average diameter (D ₅₀ ) of the inorganic filler (B) is preferably 5 μm or more, more preferably 10 μm or more, and preferably 80 μm or less, from the viewpoint of improving moldability and adhesion. Preferably it is 50 μm or less, more preferably 40 μm or less.
Here, the particle size distribution of the inorganic filler (B) can be determined by measuring the particle size distribution of particles on a volume basis using a commercially available laser diffraction particle size distribution analyzer (for example, SALD-7000 manufactured by Shimadzu Corporation). can be obtained.

The content of the inorganic filler (B) in the encapsulating resin composition improves the low hygroscopicity and low thermal expansion of the encapsulating material formed using the encapsulating resin composition, and improves the low hygroscopicity and low thermal expansion of the resulting semiconductor device. From the viewpoint of more effectively improving moisture resistance reliability and reflow resistance, it is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 65% by mass, based on the entire sealing resin composition. % or more.
In addition, from the viewpoint of more effectively improving fluidity and filling properties during molding of the encapsulating resin composition, the content of the inorganic filler (B) in the encapsulating resin composition For example, it may be 97% by mass or less, preferably 95% by mass or less, and more preferably 90% by mass or less, based on the entire product.

[Carboxylic acid dispersant (C)]
As the carboxylic acid dispersant (C), conventionally known compounds can be used without particular limitation as long as they can exhibit the effects of the present invention.
By using the carboxylic acid dispersant (C), the elastic modulus of the cured resin composition for sealing decreases, and when it is provided on a base material as a sealing material for a wafer level package, warping can be reduced. can.
From the viewpoint of the effects of the present invention, the carboxylic acid dispersant (C) preferably contains at least one compound represented by the following general formula (1).

In the general formula (1), R is a hydrogen atom, a carboxyl group, a hydroxyl group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkylcarboxyl group having 1 to 5 carbon atoms, or 1 to 5 carbon atoms. -5 alkoxycarboxyl group, an alkyl alcohol group having 1 to 5 carbon atoms, and an alkoxy alcohol group having 1 to 5 carbon atoms, and multiple R's may be the same or different.
R is preferably a carboxyl group, a hydroxyl group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or an alkylcarboxyl group having 1 to 5 carbon atoms.

X is an oxygen atom, an alkylene group having 1 to 30 carbon atoms, a divalent chain hydrocarbon group having 1 to 30 carbon atoms having one or more double bonds, or 2 having 1 to 30 carbon atoms having one or more triple bonds; represents a valent chain hydrocarbon group, and a plurality of X's may be the same or different. Examples of the divalent chain hydrocarbon group include an alkylene group.
X is preferably an oxygen atom, an alkylene group having 1 to 20 carbon atoms, or a divalent chain hydrocarbon group having 1 to 20 carbon atoms having one or more double bonds; An alkylene group having one double bond and having 1 to 20 carbon atoms is preferable.
n represents an integer of 0 to 20, and m represents an integer of 1 to 5.

The compound represented by general formula (1) is preferably a compound represented by general formula (1a) or general formula (1b) below. The carboxylic acid dispersant (C) can contain at least one selected from these.

In general formula (1a), R, m, and n have the same meanings as in general formula (1).

In the general formula (1b), Q represents an alkylene group having 1 to 5 carbon atoms, preferably an alkylene group having 1 to 3 carbon atoms. X ¹ is an alkylene group having 1 to 30 carbon atoms, a divalent chain hydrocarbon group having 1 to 30 carbon atoms having one or more double bonds, or a divalent chain hydrocarbon group having 1 to 30 carbon atoms having one or more triple bonds. A chain hydrocarbon group is preferable, such as an alkylene group having 10 to 30 carbon atoms, a divalent chain hydrocarbon group having 10 to 30 carbon atoms having one or more double bonds, and 10 to 30 carbon atoms having one or more triple bonds. More preferred are divalent chain hydrocarbon groups, and particularly preferred are divalent chain hydrocarbon groups having 10 to 30 carbon atoms and having one or more double bonds.

In this embodiment, the carboxylic acid dispersant (C) may include a polycarboxylic acid dispersant having two or more carboxyl groups.

The acid value of the carboxylic acid dispersant (C) is 5 to 500 mgKOH/g, preferably 10 to 350 mgKOH/g, and more preferably 15 to 100 mgKOH/g.
The carboxylic acid dispersant (C) is preferably solid or waxy.

From the viewpoint of the effects of the present invention, the content of the carboxylic acid dispersant (C) is preferably 0.05% by mass or more and 10% by mass or less, more preferably 100% by mass or less, based on 100% by mass of the encapsulating resin composition. The content is 0.1% by mass or more and 5% by mass or less, more preferably 0.2% by mass or more and 5% by mass or less.

Examples of the compound represented by the general formula (1) contained in the carboxylic acid dispersant (C) include Hypermer KD-4 (mass average molecular weight: 1700, acid value: 33 mgKOH/g) and Hypermer KD manufactured by CRODA. -9 (mass average molecular weight: 760, acid value: 74 mgKOH/g), Hypermer KD-12 (mass average molecular weight: 490, acid value: 111 mgKOH/g), Hypermer KD-16 (mass average molecular weight: 370, acid value: 299mgKOH/g).

[Low stress agent (D)]
The sealing resin composition of this embodiment can contain a low stress agent (D). As the low stress agent (D), silicone oil can be mentioned.

The silicone oil preferably includes organically modified silicone oils such as epoxy-modified silicone oils, carboxyl-modified silicone oils, alkyl-modified silicone oils, and polyether-modified silicone oils. Among these, it is particularly preferable to include polyether-modified silicone oil from the viewpoint of finely dispersing silicone oil in the resin component and contributing to suppressing warpage.

The content of silicone oil is preferably 0.01% by mass or more and 5% by mass or less, more preferably 0.05% by mass or more and 3% by mass or less based on the entire sealing resin composition. By controlling the content of silicone oil within such a range, it is possible to contribute to suppressing the warping of a molded product obtained by sealing an electronic element, etc. on a base material with a sealing resin composition. .

In this embodiment, other low stress agents other than silicone oil may be included, and specific examples include silicones such as silicone rubber, silicone elastomer, and silicone resin; acrylonitrile butadiene rubber; and the like.

[Coupling agent (E)]
The sealing resin composition of this embodiment can contain a coupling agent (E).
Examples of the coupling agent (E) include aminosilanes such as epoxysilane, mercaptosilane, and phenylaminosilane. From the viewpoint of improving the adhesion between the sealing material and the metal member, the coupling agent (E) is preferably epoxysilane or aminosilane, more preferably secondary aminosilane. From the same point of view, the coupling agent (E) is preferably one or more selected from the group consisting of phenylaminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane and 3-mercaptopropyltrimethoxysilane. be.

The content of the coupling agent (E) in the encapsulating resin composition is preferably 0 with respect to the entire encapsulating resin composition from the viewpoint of obtaining preferable fluidity during molding of the encapsulating resin composition. The content is .01% by mass or more and 2.0% by mass or less, more preferably 0.05% by mass or more and 1.0% by mass or less.

[Other ingredients]
The sealing resin composition of the present embodiment may contain components other than those described above, such as a curing agent, a fluidity imparting agent, a mold release agent, an ion scavenger, a flame retardant, a coloring agent, an antioxidant, etc. One or more of the various additives may be appropriately blended.

The curing agent can include a phenolic resin.
As the phenol resin, those commonly used in sealing resin compositions can be used as long as the effects of the present invention are achieved.

Phenol resins include, for example, phenols such as phenol novolac resins and cresol novolac resins, phenols such as cresol, resorcinol, catechol, bisphenol A, bisphenol F, phenylphenol, aminophenol, α-naphthol, β-naphthol, and dihydroxynaphthalene. Novolac resin obtained by condensing or co-condensing formaldehyde or ketones with formaldehyde or ketones under an acidic catalyst, phenol aralkyl resin having a biphenylene skeleton synthesized from the above-mentioned phenols and dimethoxyparaxylene or bis(methoxymethyl)biphenyl, Examples include phenol aralkyl resins such as phenol aralkyl resins having a phenylene skeleton, and phenol resins having a trisphenylmethane skeleton. These may be used alone or in combination of two or more.

<Sealing resin composition>
The encapsulating resin composition of this embodiment is solid at room temperature (25°C), and its shape can be selected depending on the molding method of the encapsulating resin composition, such as tablet form; powder form. , particulate forms such as granules; and sheet forms.

In addition, regarding the method for producing the resin composition for sealing, for example, the above-mentioned components are mixed by known means, further melt-kneaded using a kneading machine such as a roll, kneader, or extruder, cooled, and then pulverized. It can be obtained by a method. Further, after pulverization, the resin composition for sealing may be molded to obtain a particulate or sheet-like sealing resin composition. For example, a particulate sealing resin composition may be obtained by compression molding into a tablet shape. Alternatively, a sheet-shaped sealing resin composition may be obtained using, for example, a vacuum extruder.
The sealing resin composition of this embodiment can be used for transfer molding, injection molding, or compression molding.
Furthermore, by using the encapsulating resin composition obtained in this embodiment, a semiconductor device with excellent product reliability can be obtained.

Next, the physical properties of the sealing resin composition or its cured product will be explained.
The sealing resin composition of this embodiment has a spiral flow length of 70 cm or more, preferably 80 cm or more, and more preferably 90 cm or more. Therefore, the sealing resin composition of this embodiment has excellent moldability.

In the spiral flow test, for example, using a low-pressure transfer molding machine (KTS-15 manufactured by Kotaki Seiki Co., Ltd.), injection is performed at a mold temperature of 175°C into a mold for spiral flow measurement according to EMMI-1-66. This can be done by injecting the sealing resin composition under conditions of a pressure of 6.9 MPa and a curing time of 120 seconds, and measuring the flow length.

The cured product obtained from the encapsulating resin composition of this embodiment has a lower bending elastic modulus than conventional cured products (encapsulating materials), so it is difficult to suppress warping of the base material in wafer level packaging applications. can.
When the sealing resin composition of the present embodiment is cured at 175° C. for 120 seconds, the cured product has a flexural modulus of elasticity at room temperature (25° C.) of preferably 8,000 N/mm or ^more 20, 000 N/mm ² or less, more preferably 9,000 N/mm ² or more and 18,000 N/mm ² or less.

Moreover, since the cured product obtained from the sealing resin composition of this embodiment has high bending strength, it is possible to provide a sealing material with excellent mechanical strength and product reliability.
When the sealing resin composition of the present embodiment is cured at 175°C for 120 seconds, the cured product has a bending strength at room temperature (25°C) of preferably 40 N/mm ² or more, more preferably 45 N. / ^mm2 or more. Although the upper limit is not particularly limited, it can be set to 200 N/mm ² or less.

When the sealing resin composition of this embodiment is cured at 175°C for 120 seconds, the glass transition temperature of the cured product is preferably 100°C or higher, more preferably 120°C or higher. Although the upper limit is not particularly limited, it can be set to 300°C or less.

The encapsulating resin composition of this embodiment can be used for encapsulating semiconductor elements, and is not limited to encapsulating semiconductor elements, but can also be used for encapsulating other elements, and for ECU (engine control unit). It can be used for various sealing applications such as bulk sealing and rotor core sealing. When used for sealing a semiconductor element, examples of the semiconductor element include an integrated circuit, a large-scale integrated circuit, a transistor, a thyristor, a diode, and a solid-state image sensor. Examples of the structure of a semiconductor package including a semiconductor element include a ball grid array (BGA), a MAP type BGA, and the like. We also offer wafer level packages (WLPs) such as chip size packages (CSPs), quad flat non-leaded packages (QFNs), embedded WLPs (eWLPs), Fan In WLPs and Fan Out WLPs, and small outline non-leaded packages. Examples include leaded package (SON) and lead frame BGA (LF-BGA).
It is particularly preferable that the sealing resin composition according to this embodiment be used in a wafer level package (WLP).

(Method for manufacturing semiconductor packages)
As a method for manufacturing a semiconductor package according to this embodiment, a method for manufacturing a wafer level package (WLP) will be described.
FIG. 1 shows an example of a method for manufacturing a wafer level package.

A method for manufacturing a wafer level package is, for example, by arranging multiple electronic components (semiconductor chips) on a base material to form a circuit surface, and then sealing to cover the circuit surface on the base material. further, after the sealing process, the sealing resin composition covers the circuit surface of the base material, and the base material is cut to separate the electronic device into individual pieces. Including the oxidation process.
Incidentally, as the arrangement step, for example, bumps may be formed on the circuit surface. Further, as the sealing process, the bumps may be exposed from the sealing material layer by scraping the sealing material layer. Furthermore, after the sealing process, solder balls may be connected to the bumps as a wiring process.

The method for manufacturing a wafer level package will be explained in detail along with each step shown in FIGS. 1(a) to 1(f).
First, as an arrangement step, a plurality of electronic components 21 are arranged on a base material 10 such as a wafer, for example, as shown in FIG. 1(a). As shown in FIG. 1(b), a bump 22 such as a metal post is formed on the electronic component 21 to electrically connect the electronic component to a solder ball, which will be described later.

Next, as a sealing step, the electronic component 21 described above is sealed using a sealing resin composition to form a sealing material layer 30 (FIG. 1(c)). Next, the base material is fixed using a vacuum chuck or the like, and the surface of the sealant layer 30 is polished using a surface grinder or the like to expose the bumps 22 from the sealant layer 30 (FIG. 1(d)).
The sealing resin composition of this embodiment has a predetermined composition, and the amount of warpage of the cured product of the composition is less than a predetermined value, so that when a sealant is formed on a base material, the surface It is possible to provide an encapsulant that is uniformly polished, and furthermore, wiring to be formed in subsequent steps can be accurately formed on the encapsulant, resulting in an excellent yield of semiconductor package products.

Next, as a wiring process, solder balls 96 are connected to the bumps 22, for example, as shown in FIG. 1(e). Further, a wiring layer can also be formed on the surface of the sealing material.
Next, as a singulation step, for example, as shown in FIG. 1F, the sealing material layer 30 and the base material 10 are cut with a dicing blade, a laser, or the like to obtain the electronic device 50. Note that the number of bumps 22 and solder balls 96 connected to the electronic device 50 to be diced is not limited, and can be set depending on the type of the electronic device 50.

Here, in this embodiment, compression molding using a granular sealing resin composition will be outlined.

First, a granular sealing resin composition is uniformly spread on the bottom surface of the lower mold cavity of a compression molding mold. For example, the granular sealing resin composition may be transported using a transport means such as a vibrating feeder and placed on the bottom surface of the lower mold cavity.

Subsequently, the base material 10 on which the electronic component 21 is formed is fixed to the upper die of a compression mold by a fixing means such as a clamp or suction. Subsequently, by narrowing the distance between the upper mold and the lower mold under reduced pressure, the granular sealing resin composition is heated to a predetermined temperature in the lower mold cavity and becomes molten. Subsequently, the upper mold and the lower mold of the mold are combined to press the molten sealing resin composition against the electronic component 21 fixed to the upper mold. Thereafter, the sealing resin composition is cured over a predetermined period of time while maintaining the state in which the upper mold and the lower mold are combined. Thereby, the sealing material layer 30 that seals the electronic components 21 and bumps 22 on the base material 10 can be formed.
In this embodiment, even when a sheet-like sealing resin composition is used instead of a granular sealing resin composition, compression molding as described above can be used.

Here, when performing compression molding, it is preferable to perform sealing while the inside of the mold is under reduced pressure, and it is more preferable to perform the sealing under vacuum conditions. Thereby, the electronic component 21, the bumps 22, etc. can be buried with the cured product of the sealing resin composition (sealing material layer 30) without leaving any filled portions.

The molding temperature in compression molding may be, for example, 100°C or more and 200°C or less, or 120°C or more and 180°C or less. The molding pressure may be, for example, 0.5 MPa or more and 12 MPa or less, or 1 MPa or more and 10 MPa or less. The molding time may be, for example, 30 seconds or more and 15 minutes or less, or 1 minute or more and 10 minutes or less. In this embodiment, by setting the molding temperature, pressure, and time within the above ranges, it is possible to prevent portions from being filled with the molten sealing material.

Further, the cured product of the obtained sealing resin composition may be post-cured after sealing. The post-cure temperature may be, for example, 150°C or more and 200°C or less, or 165°C or more and 185°C or less. The post-cure time may be, for example, 1 hour or more and 5 hours or less, or 2 hours or more and 4 hours or less.

Although the embodiments of the present invention have been described above with reference to the drawings, these are merely examples of the present invention, and various configurations other than those described above may also be adopted.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to the description of these Examples.

<Examples 1-2, Comparative Examples 1-2 (manufacture of sealing resin composition)>
Each component listed in Table 1 was mixed in the listed quantitative ratio to obtain a mixture. Mixing was performed using a Henschel mixer at room temperature.
Thereafter, the mixture was roll-kneaded at 70 to 100°C to obtain a kneaded product. The obtained kneaded material was cooled and then crushed to obtain a sealing resin composition. Each component listed in Table 1 is as follows.

(Inorganic filler)
・Inorganic filler 1: Amorphous silica/crystalline silica (manufactured by Ryumori Co., Ltd., product name: MUF-4V, average particle size D ₅₀ = 3.8 μm)
・Inorganic filler 2: Fine powder silica (manufactured by Admatex, product name: SC-2500-SQ, average diameter 0.5 μm)
・Inorganic filler 3: Fine powder silica (manufactured by Admatex, product name: SC-5500-SQ, average diameter 1.5 μm)

(colorant)
Colorant 1: Carbon black (manufactured by Tokai Carbon Co., Ltd.)

(coupling agent)
Coupling agent 1: N-phenylaminopropyltrimethoxysilane represented by the following formula (S1) (manufactured by Dow Corning Toray, CF-4083)

(Carboxylic acid dispersant)
- Dispersant 1: Hypermer KD-9 (compound represented by the above general formula (1a), mass average molecular weight: 760, acid value: 74 mgKOH/g, manufactured by CRODA)

(Epoxy resin)
・Epoxy resin 1: Biphenyl type epoxy resin (Mitsubishi Chemical Corporation, YX-4000K)
・Epoxy resin 2: Biphenyl type epoxy resin (manufactured by Mitsubishi Chemical Corporation, YL6677)
・Epoxy resin 3: Biphenylaralkyl epoxy resin (manufactured by Nippon Kayaku Co., Ltd., NC-3000)

(hardening agent)
・Curing agent 1: Biphenylene skeleton-containing phenol aralkyl type phenol resin (manufactured by Meiwa Kasei Co., Ltd., MEH-7851SS)
・Curing agent 2: Orthocresol novolak type phenol curing agent (manufactured by Sumitomo Bakelite Co., Ltd., PR-55617)

(Release agent)
Mold release agent 1: Diethanolamine dimontanoic acid ester (NC-133, manufactured by Ito Oil Co., Ltd.)

(ion scavenger)
・Ion scavenger 1: Hydroxitalcite (Toagosei)

(hardening accelerator)
・Curing accelerator 1: Tetraphenylphosphonium bis(naphthalene-2,3-dioxy)phenyl silicate ・Curing accelerator 2: Tetraphenylphosphonium 4,4'-sulfonyl diphenolate

(Additive)
・Additive 1: Carboxyl group-terminated butadiene/acrylonitrile copolymer (CTBN1008SP, manufactured by Ube Industries, Ltd.)

(Low stress agent)
・Silicone oil 1: Epoxy/polyether modified silicone oil (FZ-3730, Toray Dow)
・Silicone oil 2: 66.1 parts by weight of epoxy resin (bisphenol A epoxy resin) [manufactured by Javan Epoxy Resin Co., Ltd., jER (registered trademark) YL6810, softening point 45°C, epoxy equivalent 172] heated at 140°C Melt and add 33.1 parts by weight of organopolysiloxane (obtained by mixing undecylenic acid and organopolysiloxane and reacting at 80°C under a platinum catalyst) and 0.8 parts by weight of triphenylphosphine. Melt mixing was performed for 30 minutes to obtain a molten reactant.

<Evaluation>
Evaluation samples were prepared using the resin compositions obtained in each example or the compositions in the following manner, and the adhesion and reliability of the obtained samples were evaluated by the following methods.

[warp]
Using a compression molding machine, the sealing resin composition was compression molded at 150°C for 300 seconds on a silicon wafer with a thickness of 775 μm and a diameter of 12 inches, and then Post Mold Cure (PMC) was performed at 150°C for 4 hours. ) to obtain a 400 μm thick cured product of the sealing resin composition. Place the obtained silicon wafer with the cured product so that the silicon wafer surface is in contact with a horizontal precision stone surface plate (manufactured by Niigata Seiki Co., Ltd., G4560), and place the silicon wafer surface in contact with a precision stone surface plate (manufactured by Niigata Seiki Co., Ltd., G4560) at 8 points where the outer periphery is divided into 8 equal parts. The height from to the silicon wafer is measured, and the average value of the heights at eight points is defined as the amount of wafer warpage [mm].

[Spiral flow (SF)]
A spiral flow test was conducted using the sealing resin compositions of Examples and Comparative Examples.
The test was conducted using a low-pressure transfer molding machine (KTS-15 manufactured by Kotaki Seiki Co., Ltd.) at a mold temperature of 175°C and an injection pressure of 6. The sealing resin composition was injected under the conditions of .9 MPa and curing time of 120 seconds, and the flow length was measured. The larger the value, the better the fluidity.

[Gel Time (GT)]
After melting the sealing resin compositions of Examples and Comparative Examples on a hot plate heated to 175° C., the time (in seconds) until hardening was measured while kneading with a spatula.

(NGFP)
The rectangular channel pressure (rectangular pressure) of the sealing resin composition obtained in each example was measured as follows. First, using a low-pressure transfer molding machine (manufactured by NEC Corporation, 40t manual press), a mold with a width of 13 mm, a thickness of 0.5 mm, and a length of 175 mm was formed at a mold temperature of 175°C and an injection speed of 24.7 mm/sec. A sealing resin composition was injected into a rectangular channel. At this time, a pressure sensor embedded at a position 25 mm from the upstream end of the flow path measures the change in pressure over time, and the lowest pressure (kgf/cm ² ) during the flow of the sealing resin composition is measured. is the rectangular pressure. The rectangular pressure is a parameter of melt viscosity, and a smaller value indicates a lower melt viscosity.

(Coefficient of linear expansion (CTE1 and CTE2),)
It was measured using the following procedure.
(1) Using a transfer molding machine, the sealing resin composition was injection molded under the conditions of a mold temperature of 175°C, an injection pressure of 10.0 MPa, and a curing time of 120 seconds to obtain a molded product of 15 mm x 4 mm x 3 mm. Ta.
(2) The obtained molded product was heated in an oven at 175° C. for 4 hours to fully cure it. Then, a test piece (cured product) for measurement was obtained.
(3) Measurement was performed using a thermomechanical analyzer (TMA100, manufactured by Seiko Electronics Industries, Ltd.) under conditions of a measurement temperature range of 0° C. to 320° C. and a heating rate of 5° C./min. From the measurement results, the coefficient of linear expansion (CTE1) at 40 to 80°C and the coefficient of linear expansion (CTE2) at 190 to 230°C were calculated. The units of CTE1 and CTE2 are ppm/°C.

[Evaluation of mechanical strength (bending strength and flexural modulus)]
The sealing resin composition was placed in a mold using a low-pressure transfer molding machine (KTS-30 manufactured by Kotaki Seiki Co., Ltd.) under conditions of a mold temperature of 175°C, an injection pressure of 10.0 MPa, and a curing time of 120 seconds. Injection molded. As a result, a molded product with a width of 10 mm, a thickness of 4 mm, and a length of 80 mm was obtained. Next, the obtained molded article was post-cured at 175° C. for 4 hours. In this way, a test piece for mechanical strength evaluation was prepared. Then, the bending strength (N/mm ² ) and bending elastic modulus (N/mm ² ) of the test piece at 260° C. or room temperature (25° C.) were measured in accordance with JIS K 6911.

(Modulus at room temperature/Modulus at heat)
The thermal elastic modulus of the cured product was measured by the following method according to JISK-6911. First, the sealing resin composition was injection molded using a low-pressure transfer molding machine (KTS-15 manufactured by Kotaki Seiki Co., Ltd.) at a mold temperature of 175°C, an injection pressure of 6.9 MPa, and a curing time of 120 seconds. A test piece of 4 mm x 4 mm was obtained. Next, this test piece was heated at a temperature of 0°C to 300°C at a rate of 5°C/min using a three-point bending method using a DMA measuring device (manufactured by Seiko Instruments), and the cured product was measured at 25°C. The room temperature storage elastic modulus (E1) and the hot storage elastic modulus (E2) of the cured product at 260°C were measured. Note that the unit is MPa.

[Glass transition temperature (Tg)]
The glass transition temperature Tg (° C.) can be measured, for example, by the following method. First, a resin composition for semiconductor encapsulation is injection molded using a transfer molding machine at a mold temperature of 175° C., an injection pressure of 9.8 MPa, and a curing time of 3 minutes to obtain a test piece of 15 mm x 4 mm x 4 mm. Next, the obtained test piece was post-cured at 175°C for 4 hours, and then measured using a thermomechanical analyzer (TMA100, manufactured by Seiko Electronics Co., Ltd.) at a temperature range of 0°C to 320°C and a heating rate. Measurement is performed under conditions of 5°C/min. From this measurement result, the glass transition temperature Tg (° C.) is calculated.

As shown in Table 1, since the sealing resin composition of the example contains a predetermined component, the cured product of the composition has a low elastic modulus, and furthermore, the amount of warpage of the cured product of the composition has a predetermined value. Because of the following, when used as a encapsulating material for a wafer level package, the surface can be polished uniformly, and furthermore, the wiring formed in the subsequent process can be accurately formed on the encapsulating material, so it is possible to polish the surface uniformly when used as a encapsulating material for a semiconductor package. It was estimated that the product yield would be excellent.

10 Base material 21 Electronic component 22 Bump 30 Encapsulant layer 50 Electronic device 96 Solder ball

Claims (10)

A sealing resin composition used for a wafer level package, comprising:
(A) an epoxy resin;
(B) an inorganic filler;
(C) a carboxylic acid dispersant;
A sealing resin composition, wherein the amount of warpage of a cured product of the sealing resin composition measured under the following conditions is 1.1 mm or less.
(conditions)
Using a compression molding machine, the sealing resin composition was compression molded at 150°C for 300 seconds on a silicon wafer with a thickness of 775 μm and a diameter of 12 inches, and then Post Mold Cure (PMC) was performed at 150°C for 4 hours. ) to obtain a 500 μm thick cured product of the sealing resin composition. Place the obtained silicon wafer with the cured product so that the silicon wafer surface is in contact with a horizontal precision stone surface plate, and measure the height from the precision stone surface plate to the silicon wafer at 8 points by dividing the outer periphery into 8 equal parts. The average value of the heights of the eight points is defined as the amount of wafer warpage [mm]. The resin composition for sealing according to claim 1, wherein the cured product of the resin composition for sealing has a bending elastic modulus at room temperature of 25°C of 8,000 N/mm ² or more and 20,000 N/mm ^{2 or} less. The sealing resin composition according to claim 1, wherein the cured product of the sealing resin composition has a bending strength of 40 N/mm ² or more at room temperature of 25°C. The sealing resin composition according to any one of claims 1 to 3, wherein a cured product of the sealing resin composition has a glass transition temperature of 100° C. or higher. The sealing resin composition according to any one of claims 1 to 4, wherein the carboxylic acid dispersant (C) contains at least one compound represented by the following general formula (1).

(In the general formula (1), R is a carboxyl group, a hydroxyl group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkylcarboxyl group having 1 to 5 carbon atoms, or a carboxyl group having 1 to 5 carbon atoms. represents an alkoxycarboxyl group, an alkyl alcohol group having 1 to 5 carbon atoms, and an alkoxy alcohol group having 1 to 5 carbon atoms, and multiple R's may be the same or different. 30 alkylene group, a divalent chain hydrocarbon group having 1 to 30 carbon atoms having one or more double bonds, and a divalent chain hydrocarbon group having 1 to 30 carbon atoms having one or more triple bonds, Multiple Xs may be the same or different. n is an integer from 0 to 20, and m is an integer from 1 to 5.) The sealing resin composition according to any one of claims 1 to 5, wherein the content of the carboxylic acid dispersant (C) is 0.05% by mass or more and 5.0% by mass or less. The sealing resin composition according to any one of claims 1 to 6, wherein the epoxy resin (A) has a biphenylaralkyl structure. The sealing resin composition according to any one of claims 1 to 7, further comprising a low stress agent (D). The sealing resin composition according to claim 8, wherein the low stress agent (D) contains polyether-modified silicone oil. a step of arranging a plurality of semiconductor chips on a base material;
A step of sealing the semiconductor chip with a cured product of the sealing resin composition according to any one of claims 1 to 9 on the base material on which the semiconductor chip is disposed;
a step of singulating the semiconductor chip;
A method of manufacturing a semiconductor package including:

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