JP2007246665A - Epoxy resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an epoxy resin composition having excellent filling properties and productivity, surely reinforcing a small-sized semiconductor device such as a CSP (chip size package) or an LGA (land grid array) connected onto a wiring board and used as a sealing material having excellent connection reliability during a heat cycle treatment. <P>SOLUTION: The epoxy resin composition comprises an epoxy resin, a curing agent and an inorganic filler and is used for sealing a space between a semiconductor package and a substrate electrically connected to the semiconductor package, The epoxy resin composition is characterized in that the viscosity of the curing agent at 25°C is 0.01-0.6 Pa s. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an epoxy resin composition for an underfill material that seals between a semiconductor device such as CSP or BGA and a circuit board to which the semiconductor device is electrically connected.

In recent years, mobile terminals such as mobile phones, digital cameras, and video cameras have been reduced in size and weight, semiconductor devices on a substrate have also been highly integrated, and small electronic components such as CSP and LGA have been increasingly used. . Since these semiconductor devices have a high degree of integration, the connection area is small, and they are more susceptible to vibration and thermal stress than in the past. In view of such a background, a sealing material (underfill material) is filled and cured in the gap between the semiconductor package and the substrate.
This underfill material is applied to prevent a semiconductor device connected to a board such as a mother board from being disconnected or dropped due to vibration or thermal stress, and fills the gaps in the connection part to protect the solder connection part. It is used for the purpose of preventing an excessive stress from acting on the solder joint between the semiconductor device and the substrate.

  The filling method of the underfill material includes a capillary flow method in which the underfill material is applied along the outer periphery of the chip or the package and is filled by utilizing a capillary phenomenon, and the underfill material is dropped in advance on the filling place. There are two types of compression flow methods, in which the chip or package is placed on top of this, but since the capillary flow method is a natural penetration method, if the viscosity of the underfill material is too high, it takes a long time to fill and the productivity decreases. To do.

  The underfill material often does not contain a filler in order to improve the filling property in the gap between the semiconductor device and the motherboard, but recently, with the high integration of components to be connected as described above, There is a strong demand for improving the life during heat cycle treatment, and a technique for blending an inert inorganic filler has been disclosed for the purpose of reducing the linear expansion coefficient of the underfill material. (For example, refer to Patent Document 1).

When improving the connection reliability at the time of heat cycle processing, the stress concentration on the solder connection portion can be suppressed by reducing the linear expansion coefficient of the underfill material and approximating the linear expansion coefficient of the package or PCB. Therefore, the linear expansion coefficient of the epoxy resin composition can be further reduced by increasing the blending amount of the filler having a small linear expansion coefficient.
However, since the viscosity of the composition increases with the blending of the inorganic filler, there is a problem that when used as an underfill material, the filling property is lowered and the productivity is impaired.

JP 2000-260820 A

  The present invention has excellent filling properties, can reliably reinforce small semiconductor devices such as CSP and LGA connected on a wiring board, has excellent connection reliability during heat cycle processing, and is used as a sealing material. The epoxy resin composition used is provided.

Such an object is achieved by the following present inventions (1) to (4).
(1) An epoxy resin composition containing an epoxy resin, a curing agent, and an inorganic filler, and used for sealing between a semiconductor package and a substrate to which the semiconductor package is electrically connected. An epoxy resin composition, wherein the curing agent has a viscosity at 25 ° C. of 0.01 to 0.6 Pa · s.
(2) The epoxy resin composition according to claim 1, wherein the curing agent contains an acid anhydride.
(3) The epoxy resin composition according to claim 1 or 2, wherein the content of the curing agent is 10 to 150 parts by weight with respect to 100 parts by weight of the epoxy resin.
(4) The epoxy resin composition according to any one of claims 1 to 3, wherein the inorganic filler contains substantially spherical fused silica.
(5) The epoxy resin composition according to claim 4, wherein the fused silica has an average particle size of 0.5 to 20 μm.

  According to the present invention, it has excellent filling properties, can reliably reinforce small semiconductor devices such as CSP and LGA connected on a wiring board, has excellent connection reliability during heat cycle processing, and is sealed. An epoxy resin composition used for the material can be provided.

Below, the epoxy resin composition of this invention is demonstrated.
The epoxy resin composition of the present invention (hereinafter sometimes simply referred to as “composition”) contains an epoxy resin, a curing agent, and an inorganic filler, and a semiconductor package and the semiconductor package are electrically connected to each other. An epoxy resin composition used for sealing between the substrate and the substrate to be formed, wherein the curing agent has a viscosity of 0.01 to 0.6 Pa · s at 25 ° C.

  Although it does not specifically limit as an epoxy resin used for the composition of this invention, What has two or more glycidyl groups in a molecule | numerator is preferable, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type In addition to bisphenol-type epoxy resins such as epoxy resins, alicyclic epoxy resins, and novolak-type epoxy resins, polyglycidyl ethers obtained by reacting catechol, resorcinol, or polyhydric alcohols such as glycerin and polyethylene glycol with epichlorohydrin are also available. Can be used. Also, obtained by reacting epichlorohydrin with glycidyl ether ester obtained by reacting hydroxycarboxylic acids such as P-hydroxybenzoic acid and β-hydroxynaphthoic acid with epichlorohydrin, or polycarboxylic acids such as phthalic acid and terephthalic acid. Polyglycidyl ester, epoxidized phenol novolak resin, epoxidized cresol novolak resin, and the like can also be used, and these may be used alone or in combination.

  The form of the epoxy resin is not particularly limited and may be liquid or solid, but bisphenol A type and bisphenol F type epoxy resins that are liquid after mixing and dissolution, and have a relatively low molecular weight and low viscosity are preferable. Thereby, even when the compounding rate of the inorganic filler mentioned later is high, suitable filling property and fluidity | liquidity as an underfill material can be provided.

  Examples of the curing agent used in the composition of the present invention include acid anhydrides, imidazole compounds, aromatic amines, aliphatic amines, tertiary amines, phenol resins, hydrazine compounds, amide compounds, and cationic polymerization initiators. Is mentioned. Among these, it is preferable to use an acid anhydride in terms of cured product characteristics and workability.

  The curing agent used in the composition of the present invention is characterized by having a viscosity at 25 ° C. of 0.01 to 0.6 Pa · s. By using a curing agent having a viscosity at 25 ° C. in the above range, particularly the filling property of the composition can be remarkably improved. This is because the increase in viscosity due to high filling of the filler for the purpose of reducing the coefficient of thermal expansion of the cured resin can be reduced by blending with a low viscosity curing agent, so that a decrease in filling property can be suppressed. .

  Moreover, it is preferable that content of the said hardening | curing agent is 10-150 weight part with respect to 100 weight part of epoxy resins. More preferably, it is 10-130 weight part. By setting the content of the curing agent in the above range, it is possible to optimize the balance between the properties of the cured product and the filling property.

  The curing agent used in the composition of the present invention can be used in combination with another curing agent such as an imidazole compound or an amine compound as a curing accelerator in order to improve curability. When applied to a one-pack type resin composition, a resin composition having an excellent balance between fillability and curability can be obtained by using an acid anhydride as a main component and using an imidazole compound in combination.

Since the viscosity of the curing agent increases greatly when a high-viscosity epoxy resin is used or when a filler such as silica is highly filled, it is preferable to use a curing agent with as low a viscosity as possible.
In addition, the curing rate can be increased by combining with an imidazole compound or an amine compound, but it is desirable that the viscosity does not increase as much as possible.

Examples of the acid anhydride include dodecenyl succinic anhydride, methyl hymic anhydride, 4-methylhexahydrophthalic anhydride, 3-methyltetrahydrophthalic anhydride, and the like.

An imidazole compound or the like can be added to the composition of the present invention to improve reactivity, but an epoxy-imidazole adduct compound commercially available as a latent curing agent can be preferably used. Examples of commercially available products include “Amicure PN-23”, “Amicure PN-40” manufactured by Ajinomoto Fine Techno Co., “Novacure HX-3721” manufactured by Asahi Kasei Co., Ltd., “ Fuji Cure FX-1000 "and the like.
In addition, a general imidazole compound, a masterbatch type curing agent for a one-part epoxy resin disclosed in JP-A-1-70523 (a masterbatch type curing agent for a one-part epoxy resin), You may use the latent hardening agent currently disclosed by 6-73156 gazette (latent boric-acid-ester compound hardening | curing agent).

Examples of the inorganic filler used in the composition of the present invention include silica, alumina, aluminum hydroxide, and the like, but it is preferable to use substantially spherical fused silica.
The fused silica is an inorganic filler that is inert and has a small linear expansion coefficient. By blending this with the composition, the linear expansion coefficient of the composition can be reduced. By reducing the linear expansion coefficient, it is possible to reduce the occurrence of stress due to dimensional changes during heating / cooling, so that the connection reliability when used as a sealant can be improved.

In addition, by using fused silica, when the composition is filled in the gap between the semiconductor device and the wiring board, it is possible to reduce the rolling resistance of silica particles in the composition, the friction resistance due to the collision of particles, and the like. it can. Thereby, the fluidity | liquidity of a composition can be improved and the filling property at the time of using as an underfill material can be made favorable.
Furthermore, the dispersibility of the fused silica in the composition can be improved by using fused silica having a substantially spherical shape. Thereby, it is thought that generation | occurrence | production of the crack resulting from the uneven distribution of an inorganic filler, etc. can be prevented.

In the composition of the present invention, one kind of fused silica can be used alone, but those having different average particle diameters may be used in combination from the balance with separation and viscosity. Thereby, sedimentation and separation of fused silica can be suppressed and suitable fluidity can be imparted.
Such an effect can be expressed particularly effectively when the content of fused silica in the composition is high.

  The average particle size of the fused silica is preferably 0.5 to 20 μm. More preferably, it is 1-10 micrometers. Thereby, the balance of the sedimentation-separation property of the fused silica in the composition and the viscosity of the composition can be made suitable.

  In the composition of the present invention, the content of the fused silica is not particularly limited, and can be appropriately set according to the properties of the target composition. % Is preferred. More preferably, it is 15 to 70% by weight. Thereby, the balance of the fillability in the case of using as an underfill material and the connection reliability of the hardened | cured material obtained can be made suitable.

  In addition, a coupling agent can be used in the composition of the present invention as necessary. Although it does not specifically limit as content of a coupling agent, 0.3-2.0 weight part is preferable with respect to 100 weight part of fused silica. More preferably, it is 0.5 to 1.5 parts by weight. By making content of a coupling agent into the said range, the adhesiveness of an epoxy resin and a fused silica can be improved and heat cycle resistance can be improved.

  In the composition of the present invention, in addition to the above raw material components, as long as it does not contradict the purpose of the present invention, as necessary, pigments, dyes, modifiers, thixotropic agents, anti-coloring agents, anti-aging agents, Additives such as mold release agents, reactive or non-reactive diluents can be blended.

  The composition of the present invention may be either a one-component type or a two-component type divided into a main agent and a curing agent. The one-pack type has good workability because a curing agent is blended in advance, and the two-pack type is easy to store and can be cured at low temperature.

  The composition of the present invention can be produced by applying a general stirring and mixing apparatus and processing conditions similar to those for producing a normal epoxy resin composition. Examples of the device used include a mixing roll, a dissolver, a planetary mixer, a kneader, and an extrusion device. As processing conditions, you may heat in order to melt | dissolve and / or reduce viscosity of an epoxy resin etc., and to improve stirring mixing efficiency. Further, cooling may be performed in order to remove frictional heat generation, reaction heat generation, and the like. The time for stirring and mixing can be determined as necessary, and is not particularly limited.

  Hereinafter, the present invention will be described in detail by way of examples.

Example 1
40 parts by weight of a bis F type epoxy resin, 60 parts by weight of a bis A type epoxy resin, 0.5 parts by weight of a silane coupling agent are mixed with a planetary mixer, and further 20 parts by weight of an acid anhydride, 10 parts by weight of an imidazole compound, 45 parts by weight of fused silica A, 0.5 part of a colorant (carbon black) and an antifoaming agent were charged and mixed, and then kneaded with a three roll to obtain a composition.

(Example 2)
40 parts by weight of a bis F type epoxy resin, 60 parts by weight of a bis A type epoxy resin, 0.5 parts by weight of a silane coupling agent are mixed with a planetary mixer, and 50 parts by weight of an acid anhydride, 10 parts by weight of an imidazole compound, 60 parts by weight of fused silica A, 0.7 part of a colorant (carbon black) and an antifoaming agent were charged and mixed, and then kneaded with a three roll to obtain a composition.

(Example 3)
60 parts by weight of a bis F type epoxy resin, 40 parts by weight of a bis A type epoxy resin, and 2.0 parts by weight of a silane coupling agent are mixed with a planetary mixer, and further 90 parts by weight of an acid anhydride and 7.0 parts by weight of an imidazole compound. Parts, 200 parts by weight of fused silica A, 1.2 parts of a colorant (carbon black) and an antifoaming agent were charged and mixed, and then kneaded with a three roll to obtain a composition.

Example 4
60 parts by weight of a bis F type epoxy resin, 40 parts by weight of a bis A type epoxy resin, and 1.0 part by weight of a silane coupling agent are mixed with a planetary mixer, and further 90 parts by weight of an acid anhydride and 7.0 parts by weight of an imidazole compound. Parts, 100 parts by weight of fused silica A, 0.9 parts of a colorant (carbon black) and an antifoaming agent were charged and mixed, and then kneaded with a three roll to obtain a composition.

(Example 5)
A composition was obtained in the same manner using an amine compound instead of the imidazole compound of Example 4.

(Example 6)
60 parts by weight of a bis F type epoxy resin, 40 parts by weight of a bis A type epoxy resin, and 0.5 parts by weight of a silane coupling agent are mixed with a planetary mixer, and further 90 parts by weight of an acid anhydride and 7.0 parts by weight of an amine compound. Parts, 50 parts by weight of fused silica A, 0.7 parts of a colorant (carbon black) and an antifoaming agent were charged and mixed, and then kneaded with a three-roll to obtain a composition.

(Example 7)
50 parts by weight of a bis-F type epoxy resin, 50 parts by weight of an alicyclic epoxy resin, and 3.0 parts by weight of a silane coupling agent are mixed with a planetary mixer, and further 105 parts by weight of an acid anhydride and 7.0 parts by weight of an imidazole compound. Parts, 100 parts by weight of fused silica A, 200 parts by weight of fused silica B, 1.6 parts of a colorant (carbon black) and an antifoaming agent were mixed and then kneaded with three rolls to obtain a composition. .

(Example 8)
50 parts by weight of a bis-F type epoxy resin, 50 parts by weight of an alicyclic epoxy resin, and 5.0 parts by weight of a silane coupling agent are mixed with a planetary mixer, and further 120 parts by weight of an acid anhydride and 7.0 parts by weight of an imidazole compound. Parts, 150 parts by weight of fused silica A, 350 parts by weight of fused silica B, 2.2 parts of a colorant (carbon black) and an antifoaming agent were mixed and then kneaded with three rolls to obtain a composition. .

(Comparative Example 1)
60 parts by weight of bis-F type epoxy resin, 40 parts by weight of bis-A type epoxy resin, 10 parts by weight of imidazole compound, 0.3 part of colorant (carbon black) and antifoaming agent are mixed with a planetary mixer, and three more The composition was obtained by kneading with a roll.

(Comparative Example 2)
60 parts by weight of bis F type epoxy resin, 40 parts by weight of bis A type epoxy resin and 1.0 part by weight of silane coupling agent are mixed with a planetary mixer, and further 7 parts by weight of imidazole compound and 100 parts by weight of fused silica A Then, 0.6 part of a colorant (carbon black) and an antifoaming agent were charged and mixed, and then kneaded with a three roll to obtain a composition.

(Comparative Example 3)
A composition was obtained in the same manner as in Comparative Example 2 except that 90 parts by weight of acid anhydride B was additionally blended and the colorant (carbon black) was increased to 0.9 part.

  Table 1 shows the composition of the compositions of the examples. In Table 1, each compounding amount represents “part by weight”. The raw materials used are as follows.

  Moreover, the following items were evaluated about the composition obtained by the Example and the comparative example. The results are shown in Table 2. The evaluation method is as follows.

1. Raw material (1) Epoxy resin / bis F type epoxy resin: manufactured by Japan Epoxy Resin Co., Ltd. “Epicoat 807”, epoxy equivalent of about 170)
・ Bis A type epoxy resin: manufactured by Dow Chemical Co., Ltd. ・ "DER-331", epoxy equivalent of about 190)
-Alicyclic epoxy resin: manufactured by Daicel Chemical Industries, Ltd.-"Celoxide 2021P", epoxy equivalent of about 135)
(2) Curing agent / Acid anhydride A: “Rikacid MH-700” (manufactured by Shin Nippon Rika Co., Ltd.) (Methylhexahydrophthalic anhydride viscosity 0.04 Pa · s)
・ Acid anhydride B: manufactured by Shin Nippon Rika Co., Ltd. ・ "Ricacid HF-04" (viscosity 1.0 Pa.s)
・ Imidazole compounds: Ajinomoto Fine Techno Co., Ltd. ・ Amicure PN-40 (Imidazole epoxy resin adduct curing agent)
・ Amine compounds: manufactured by Fuji Kasei Kogyo Co., Ltd. ・ “FXR-1020” (polyamine)
(3) Inorganic filler / Fused silica A: “FB-01” (average particle size 2.1 μm) manufactured by Denki Kagaku Kogyo Co., Ltd.
-Fused silica B: manufactured by Denki Kagaku Kogyo Co., Ltd.-"FB-8S" (average particle size 8 μm)
(4) Coupling agent / Coupling agent A: “A-1100” manufactured by Nihon Unicar Company
(5) Pigment Made by Mitsubishi Chemical Industries, Ltd. “MA-600” (carbon black)

2. Evaluation method (1) Viscosity (25 ° C.)
Measured with an EH viscometer (manufactured by Toki Sangyo Co., Ltd.). The rotor model was a 1 ° 34 'cone.

(2) Gel time Using a hot plate at 150 ° C., the time until gelation by stirring with a spatula was measured.

(3) Filling property A 18 × 18 mm cover glass (thickness of about 0.5 mm) is bonded to a 25 × 75 mm slide glass (thickness of about 1.2 mm) through a spherical spacer of 70 μm in diameter at four corners. Created a space for. With the temperature maintained at 50 ° C., the composition was dropped on one side with a syringe, and the time until the filling space was filled with the composition was measured.

(4) Coefficient of thermal expansion The resin composition was poured into an aluminum cup having a diameter of 5 cm to a thickness of 5 mm, heated at 80 ° C. for 30 minutes + 120 ° C. for 30 minutes, and the cured product was cut into 5 × 5 × 10 mm size, and TMA (thermal machine The coefficient of thermal expansion was measured with a measuring device.

(5) Connection reliability Using a circuit board in which a 10 x 10 mm BGA (0.8 mm pitch, 121 pins, solder ball diameter 0.3 mm) is daisy chain connected, the composition is osmotically cured between the BGA and the circuit board. Then, a heat cycle treatment (-40 to 125 ° C., 125 to −40 ° C. alternately with 30 minutes each as one cycle) was performed. The continuity was checked after every 100 cycles. When the disconnection or the conduction resistance increased by 10% or more of the initial value, it was determined as NG. More than 1000 cycles were accepted.

As is apparent from the results in Table 1, Examples 1 to 8, which are epoxy resin compositions of the present invention containing a curing agent having a viscosity at 25 ° C. of 0.01 to 0.6 Pa · s, do not include this. Compared with Comparative Examples 1-3, it was excellent in filling property and connection reliability.
In Comparative Example 1, since only an imidazole compound was blended as a curing agent, although good filling properties were exhibited, the thermal expansion coefficient was high and the connection reliability was poor. The comparative example 2 was inferior to the filling property and connection reliability of the blended fused silica. In Comparative Example 3, since an acid anhydride having a viscosity at 25 ° C. of 1 Pa · s was used as the curing agent, the filling property and connection reliability were poor as in Comparative Example 2.

Claims (5)

An epoxy resin composition containing an epoxy resin, a curing agent, and an inorganic filler, and used for sealing between a semiconductor package and a substrate to which the semiconductor package is electrically connected, An epoxy resin composition, wherein the curing agent has a viscosity at 25 ° C. of 0.01 to 0.6 Pa · s. The epoxy resin composition according to claim 1, wherein the curing agent contains an acid anhydride. 3. The epoxy resin composition according to claim 1, wherein the content of the curing agent is 10 to 150 parts by weight with respect to 100 parts by weight of the epoxy resin. The epoxy resin composition according to claim 1, wherein the inorganic filler contains substantially spherical fused silica. The epoxy resin composition according to claim 4, wherein the fused silica has an average particle size of 0.5 to 20 μm.