JP2007254543A - One-pack type epoxy resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a one-pack type epoxy resin composition which improves the pot life while maintaining good permeability and connection reliability on heat cycle treatment when used as an under-filling material for sealing a gap between a semiconductor device and a substrate. <P>SOLUTION: The one-pack type epoxy resin composition comprises a bisphenol type epoxy resin having a molecular weight of 400 or more, an inorganic filler, and a silane coupling agent having a nucleophilic functional group as essential components, and the above silane coupling agent preferably contains an aminosilanes. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a one-pack type epoxy resin composition.

  In recent years, miniaturization of LSI devices has been demanded as small electronic devices such as digital cameras, integrated VTRs and mobile phones have become widespread. For this reason, the CSP or the like can be used for the purpose of downsizing and improving the characteristics of the bare chip while taking advantage of the characteristics of the conventional chip mounting package that can protect the semiconductor bare chip such as LSI and can easily perform the test. New packages such as BGA are becoming popular.

  This lead-free chip carrier includes a large number of input / output connections between a chip and a corresponding substrate in a relatively small package. A lead-free chip carrier typically consists of a package containing a single ceramic, such as alumina, which forms a chip carrier or base on which the chip is mounted. The package on which the chip is mounted is mounted on a larger printed wiring board (PCB) or the like. Specifically, a contact pad having a mirror image relationship with the contact pad of the package is formed on the PCB, and after both are aligned, it is electrically and mechanically connected by performing reflow soldering, etc. Is done. When the package is connected to the PCB by solder, solder paste is usually used or solder bumps are used. Generally, an epoxy-based sealing resin (underfill material) is injected into a gap generated by a solder bump between the package and the PCB.

  As one method for reducing the area required when mounting a chip on a package or PCB, there is a flip chip connection method. This is a method in which the connection pad on the upper surface side of the chip is directed to the lower surface side and connected to the opposing package or PCB by solder bumps. Also in this case, a gap due to solder bumps is generated between the chip element surface and the chip carrier, or between the chip element surface and the PCB, so that an underfill material is similarly injected. The underfill material not only fills the gaps and spaces in the connection part, but also seals the electrical contacts to protect them from the surroundings, and has a function of bonding the package and the PCB, for example, at a small mechanical joint. It also has the purpose of preventing an excessive force from acting on a certain solder bump joint.

Recently, due to narrow gaps and narrow pitches in solder bump joints, there is a strong demand for permeability of underfill materials and connection reliability during heat cycle processing. There is a need for low linear expansion, such as by filling. However, when the low-viscosity underfill material contains an inorganic filler, the specific gravity of the inorganic filler and other compositions is greatly different, so that the inorganic filler is liable to settle and the pot life is shortened.
In order to suppress sedimentation of the inorganic filler, researches such as adjusting the particle size of the inorganic filler have been conducted. (For example, see Patent Document 1.)

JP 2004-210901 A

The present invention improves pot life while maintaining good permeability and connection reliability during heat cycle processing when used as an underfill material for sealing between a semiconductor device and a substrate. A one-pack type epoxy resin composition is provided.

Such an object is achieved by the following present inventions (1) to (7).
(1) A one-component epoxy resin used as an underfill material for sealing between a semiconductor device and a substrate to which the semiconductor device is electrically connected, and having a molecular weight of 400 or more, A one-pack type epoxy resin composition comprising an inorganic filler and a silane coupling agent having a nucleophilic functional group as essential components.
(2) The one-pack type epoxy resin composition according to (1), wherein the silane coupling agent contains aminosilanes.
(3) The one-component epoxy resin composition according to (1) or (2), wherein the content of the silane coupling agent is 0.1 to 5% by weight with respect to the inorganic filler.
(4) The one-pack type epoxy resin composition according to any one of (1) to (3), wherein the content of the inorganic filler is 15 to 65% by weight with respect to the entire epoxy resin composition.
(5) The one-component epoxy resin composition according to any one of (1) to (4), wherein the inorganic filler includes substantially spherical fused silica.
(6) In the inorganic filler, the proportion of the substantially spherical fused silica having an average particle diameter of 0.1 to 10 μm is 95% by volume or more based on the whole inorganic filler. The one-component epoxy resin composition according to any one of the above.
(7) The one-component epoxy resin composition according to any one of (1) to (6), wherein the viscosity at 25 ° C. is 3 Pa · s or less.

According to the one-pack type epoxy resin composition of the present invention, when used as an underfill material for sealing between a semiconductor device and a substrate, good permeability and connection reliability during heat cycle treatment are obtained. Pot life can be improved by suppressing sedimentation of an inorganic filler, hold | maintaining.

Below, the one-pack type epoxy resin composition of this invention is demonstrated.
The one-pack type epoxy resin composition of the present invention (hereinafter sometimes simply referred to as “composition”) is an underfill material that seals between a semiconductor device and a substrate to which the semiconductor device is electrically connected. It is a composition used for the above, and contains a bisphenol type epoxy resin having a molecular weight of 400 or more, an inorganic filler, and a silane coupling agent having a nucleophilic functional group as essential components.

In the composition of the present invention, a bisphenol type epoxy resin having a molecular weight of 400 or more (hereinafter sometimes simply referred to as “epoxy resin”) is blended.
By using an epoxy resin having a molecular weight of 400 or more, pot life, permeability, and heat cycle resistance can be provided in a balanced manner.

The molecular weight can be measured and evaluated by, for example, GPC (Gel Permeation Chromatography). Specific examples of the GPC measurement conditions are shown below.
Tetrahydrofuran was used as an elution solvent, a differential refractometer was measured as a detector under the conditions of a flow rate of 1.0 ml / min and a column temperature of 40 ° C., and the molecular weight was converted by standard polystyrene. The equipment used is as follows.
-Body: manufactured by TOSOH-"HLC-8120"
・ Analytical column: manufactured by TOSOH ・ One "G1000HXL", two "G2000HXL", one "G3000HXL"

Although it does not specifically limit as a hardening | curing agent of the said epoxy resin, Three types, a polyaddition type, a catalyst type, and a condensation type, are mentioned.
The polyaddition type curing agent is not particularly limited. For example, aliphatic polyamines such as diethylenetriamine (DETA), triethylenetetramine (TETA), and metaxylylenediamine (MXDA), diaminodiphenylmethane (DDM), m -In addition to aromatic polyamines such as phenylenediamine (MPDA) and diaminodiphenylsulfone (DDS), polyamine compounds containing dicyandiamide (DICY), organic acid dihydrazide, hexahydrophthalic anhydride (HHPA), methyltetrahydrophthalic anhydride (MTHPA) ), Alicyclic acid anhydrides, trimellitic anhydride (TMA), pyromellitic anhydride (PMDA), acid anhydrides including aromatic acid anhydrides such as benzophenone tetracarboxylic acid (BTDA), novolac phenols resin Polyphenol compounds such as phenol polymer, polysulfide, thioester, polymercaptan compounds such as thioether, an isocyanate prepolymer, the isocyanate compounds such as blocked isocyanates, and organic acids such as carboxylic acid-containing polyester resins.

The catalyst-type curing agent is not particularly limited, and examples thereof include tertiary amine compounds such as benzyldimethylamine (BDMA) and 2,4,6-trisdimethylaminomethylphenol (DMP-30), and 2-methylimidazole. And imidazole compounds such as 2-ethyl-4-methylimidazole (EMI24), Lewis acids such as BF ₃ complex, and the like.

  The condensation type curing agent is not particularly limited, and examples thereof include phenol resins such as resol type phenol resins, urea resins such as methylol group-containing urea resins, and melamine resins such as methylol group-containing melamine resins. Can be mentioned.

These curing agents can be used alone or in combination of two or more depending on the type of epoxy resin used and the physical properties of the desired cured product. Among these, it is preferable to use a combination of hexahydrophthalic anhydride (HHPA) or methyltetrahydrophthalic anhydride (MTHPA) and an imidazole compound. Thereby, the viscosity of the composition can be lowered and the permeability can be improved while maintaining the curability at a practical level.
It is preferable that content of the hardening | curing agent used for the composition of this invention is 50-150 weight part with respect to 100 weight part of epoxy resins, More preferably, it is 70-130 weight part. By making the said hardening | curing agent content of the said range, it will become the thing which was especially excellent in balance with curability and permeability.

In the composition of the present invention, a silane coupling agent having a nucleophilic functional group is blended.
Examples of the silane coupling agent having a nucleophilic functional group include aminosilanes, mercaptosilanes, and isocyanate silanes. Of these, aminosilanes are preferred.
Examples of aminosilanes include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N- (2-aminoethyl) 3-aminopropyltrimethoxysilane, and N- (2-aminoethyl) 3-amino. Examples thereof include propylmethyldimethoxysilane and N-β (aminoethyl) γ-aminopropyltriethoxysilane.

  By blending the silane coupling agent having the nucleophilic functional group, the nucleophilic functional group reacts with the glycidyl group of the epoxy resin, and the alkanol group reacts with the inorganic filler. It is thought that it can suppress the settling of the inorganic filler and improve the pot life because the apparent specific gravity of the inorganic filler is reduced by forming a film of an epoxy resin and a silane coupling agent. It is done. Moreover, since the wettability between the epoxy resin and the inorganic filler is improved, the fluidity can be improved.

  The content of the silane coupling agent is preferably 0.1 to 5% by weight, more preferably 0.5 to 3% by weight with respect to the inorganic filler. By making the content of the silane coupling agent having the nucleophilic functional group within the above range, the balance between the permeability, the connection reliability at the time of heat cycle treatment, and the pot life can be optimized. it can.

An inorganic filler is blended in the composition of the present invention.
Examples of the inorganic filler include silica, fused silica, aluminum oxide, and aluminum nitride.
The inorganic filler is inert and has a small linear expansion. By containing this in the composition, the linear expansion coefficient of the composition can be reduced. As a result, the linear expansion of the underfill material can be approximated to that of a package or PCB, and the stress concentration on the solder bump joint can be suppressed, so that the connection reliability during the heat cycle process can be improved.

  The content of the inorganic filler is preferably 15 to 65% by weight, more preferably 25 to 45 parts by weight, based on the entire epoxy resin composition. By making content of an inorganic filler into the said range, especially permeability and the connection reliability at the time of a heat cycle process can be comprised with sufficient balance.

Among the inorganic fillers, fused silica is preferably used, and substantially spherical fused silica is more preferable.
By doing so, the rolling resistance in the composition, the frictional resistance caused by the collision of the particles, and the like can be reduced, so that the permeability can be improved.

  In the inorganic filler, the ratio of the substantially spherical fused silica having an average particle diameter of 0.1 to 10 μm is preferably 95% by volume or more based on the whole inorganic filler. More preferably, the ratio of the substantially spherical fused silica having an average particle diameter of 0.4 to 6 μm is 95% by volume or more. By doing so, in particular, the permeability and pot life can be improved in a well-balanced manner.

  The viscosity at 25 ° C. of the composition of the present invention is preferably 3 Pa · s or less. In this way, particularly excellent permeability can be achieved.

  In addition to the raw material components described above, the composition of the present invention includes pigments, dyes, modifiers, thixotropic agents, anti-coloring agents, anti-aging agents, release agents, as long as the object of the present invention is not adversely affected. Additives such as an agent, a reactive or non-reactive diluent can be blended.

  As described above, the composition of the present invention retains good permeability and connection reliability during heat cycle processing when used as an underfill material for sealing between a semiconductor device and a substrate. However, pot life can be improved by suppressing sedimentation of the inorganic filler.

Next, the manufacturing method of the composition of this invention is demonstrated.
Although it does not specifically limit as a method of manufacturing the composition of this invention, For example, an epoxy resin and a silane coupling agent are mixed, and it aged for 24 hours or more (if necessary, heats at 100 degrees C or less), and it is sufficient with an epoxy group. A method of mixing other raw material components after reacting a nucleophilic substituent is desirable.

  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 apparatus used include a mixing roll, a dissolver, a planetary mixer, a kneader, and an extrusion apparatus. 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
100 parts by weight of epoxy resin A and 1.5 parts by weight of silane coupling agent A were mixed and stirred at room temperature for 24 hours or more using a planetary mixer, and then 30 parts by weight of an imidazole compound as a curing agent. 72 parts by weight of an acid anhydride and 100 parts by weight of fused silica as an inorganic filler were blended, and the mixture was sufficiently stirred and mixed at room temperature using a planetary mixer to obtain a composition.

(Example 2)
A composition was obtained in the same manner as in Example 1 except that the amount of the silane coupling agent A was reduced to 1 part by weight.

(Example 3)
A composition was obtained in the same manner as in Example 1 except that the amount of the silane coupling agent A was increased to 2 parts by weight.

Example 4
A composition was obtained in the same manner as in Example 1 except that the amount of the silane coupling agent A was increased to 3 parts by weight.

(Example 5)
A composition was obtained in the same manner as in Experimental Example 1 except that the silane coupling agent A was replaced with the silane coupling agent B.

(Example 6)
A composition was obtained in the same manner as in Example 5 except that the amount of the silane coupling agent B was reduced to 1 part by weight.

(Example 7)
A composition was obtained in the same manner as in Example 5 except that the amount of the silane coupling agent B was increased to 2 parts by weight.

(Example 8)
A composition was obtained in the same manner as in Example 5 except that the amount of the silane coupling agent B was increased to 3 parts by weight.

(Comparative Example 1)
Inorganic filler and silane coupling agent are not added, 100 parts by weight of epoxy resin A, 30 parts by weight of imidazole compound as a curing agent, 72 parts by weight of acid anhydride are blended, and then uniformly at room temperature using a planetary mixer The composition was obtained by sufficiently stirring and mixing until dispersed.

(Comparative Example 2)
A composition was obtained in the same manner as in Comparative Example 1 except that 100 parts by weight of fused silica was additionally blended as an inorganic filler.

(Comparative Example 3)
A composition was obtained in the same manner as in Comparative Example 2 except that 1.5 parts by weight of the silane coupling agent C was additionally blended.

(Comparative Example 4)
A composition was obtained in the same manner as in Example 1 except that the epoxy resin B was used in place of the epoxy resin A.

  Table 1 shows the composition of the compositions of Examples and Comparative Examples. In the table, each compounding amount represents “part by weight”.

  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 raw materials used and the evaluation methods are as follows.

1. Raw material (1) Epoxy resin / Epoxy resin A: manufactured by Asahi Denka Kogyo Co., Ltd. “EP-4000S” (bisphenol A type epoxy resin, molecular weight 456)
-Epoxy resin B: manufactured by Dainippon Ink & Co., Ltd. "EXA-835LV" (bisphenol A type epoxy resin, molecular weight 340, bisphenol F type epoxy resin, molecular weight 312 each 50% by weight)
(2) Curing agent / Imidazole compound: Asahi Kasei Corporation “Novacure HX-3722” (Imidazole epoxy resin adduct curing agent)
・ Acid anhydride: manufactured by Shin Nippon Science Co., Ltd. “MT-500” (methyltetrahydrophthalic anhydride, acid anhydride equivalent of about 169)
(3) Inorganic filler, manufactured by Admatechs Co., Ltd. “SO-32R” (substantially spherical fused silica, average particle size 1.5 μm, average particle size 0.1-8 μm is 95% by volume or more)
(4) Silane coupling agent / silane coupling agent A: manufactured by Shin-Etsu Chemical Co., Ltd. “KBE-903” (3-aminopropyltriethoxysilane: nucleophilic functional group)
Silane coupling agent B: manufactured by Shin-Etsu Chemical Co., Ltd. “KBM-603” (N- (2-aminoethyl) 3-aminopropyltrimethoxysilane: has a nucleophilic functional group)
Silane coupling agent C: manufactured by Shin-Etsu Chemical Co., Ltd. “KBM-403” (3-glycidoxypropyltrimethoxysilane: has no nucleophilic functional group)

2. Evaluation method (1) Penetration In a state where the pine sediment sediment plate 18 × 18 mm and the gap 70 μm are maintained at 50 ° C., the composition is dropped on one side with a syringe, and the gap is filled with the composition within 3 minutes. Tested.
○: The composition could be filled within 3 minutes.
X: It took 3 minutes or more to fill the composition, or the permeation stopped midway.

(2) Connection reliability during heat treatment A circuit board on which a 10 × 10 mm BGA (0.5 mm pitch, 121 pins, solder ball diameter 0.35 mm) is mounted, and the composition is filled between the BGA and the circuit board. Then, 1000 cycles of heat cycle treatment (-40 ° C / 125 ° C for 10 minutes each). The presence or absence of poor conduction was confirmed.
A: No conduction failure occurred at the end of 1000 cycles.
X: A conduction failure occurred at the end of 1000 cycles.

(3) Pot life (25 ° C)
A 30 ml syringe manufactured by Musashi Engineering Co., Ltd. was filled with 30 g of the composition, and after standing for 24 hours in a standing state, the permeability was evaluated by the same method as in (1) above, and the time taken to fill the gap was 1. It was tested whether it was less than 5 times.
A: Less than 1.5 times the initial value.
X: 1.5 times or more of the initial value, or the penetration stopped in the middle.

(4) Viscosity (25 ° C)
It measured with the E-type viscosity meter (made by Toki Sangyo Co., Ltd.). The rotor type was 1 ° 34 "cone.

Examples 1 to 8 are one-part epoxy resin compositions of the present invention containing bisphenol type epoxy resin having a molecular weight of 400 or more, an inorganic filler, and a silane coupling agent having a nucleophilic functional group as essential components. It was proved that the permeability, the connection reliability during the heat cycle treatment, and the pot life were excellent.
On the other hand, among Comparative Examples 1 to 4 that do not contain a silane coupling agent having a nucleophilic functional group, Comparative Example 1 further does not contain an inorganic filler, so that linear expansion increases, and connection reliability during heat cycle processing is increased. Decreased. Comparative Example 2 that does not contain a silane coupling agent having a nucleophilic functional group, Comparative Example 3 that includes a silane coupling agent that does not have a nucleophilic functional group, and Comparative Example 4 that has a low molecular weight of an epoxy resin are inorganic. A sufficient film could not be formed on the surface of the filler, and the pot life was reduced.
Moreover, the viscosity in 25 degreeC of Examples 1-8 and Comparative Examples 1-4 was all 3 Pa * s or less.

Claims (7)

Bisphenol type epoxy resin having a molecular weight of 400 or more, inorganic filler, used as an underfill material for sealing between a semiconductor device and a substrate to which the semiconductor device is electrically connected And a silane coupling agent having a nucleophilic functional group as an essential component. The one-pack type epoxy resin composition according to claim 1, wherein the silane coupling agent contains aminosilanes. The one-pack type epoxy resin composition according to claim 1 or 2, wherein the content of the silane coupling agent is 0.1 to 5 wt% with respect to the inorganic filler. The content of the said inorganic filler is 15 to 65 weight% with respect to the whole epoxy resin composition, The one-pack type epoxy resin composition in any one of Claims 1-3. The one-pack type epoxy resin composition according to any one of claims 1 to 4, wherein the inorganic filler contains substantially spherical fused silica. The said inorganic filler is 95 volume% or more with respect to the said whole inorganic filler in the ratio of the said substantially spherical fused silica with an average particle diameter of 0.1-10 micrometers. One-pack type epoxy resin composition. The one-pack type epoxy resin composition according to any one of claims 1 to 6, wherein the viscosity at 25 ° C is 3 Pa · s or less.