JP2000129237A - Adhesive - Google Patents

Abstract

(57) [Problem] To provide an adhesive for bonding electronic parts, which can be stored for a long time without impairing the curing speed. SOLUTION: In a one-pack type electronic component bonding adhesive containing a curing agent and a main agent which reacts with the curing agent and thermally cures, the curing agent is contained as imidazole solid particles. Preferably, a hardening accelerator for accelerating the hardening of a main agent, for example, an epoxy resin, is further mixed as solid particles, and may further contain conductive particles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive, for example, an adhesive used for joining an electronic component such as a semiconductor chip to a substrate.

[0002]

2. Description of the Related Art In recent years, with the development of the semiconductor industry, various methods have been proposed for joining electronic components such as semiconductor chips to a substrate in addition to the conventional solder joining. Above all, there is a strong tendency to use an adhesive instead of solder in consideration of cost, bonding temperature, environmental aspect and the like.

Heretofore, adhesives for bonding electronic parts have long been hardened, and cannot sufficiently reduce the stress generated between the bonded semiconductor chip and the substrate. For this reason, the adhesive for electronic component bonding is required to be devised so as to solve the above-mentioned disadvantages.

As an adhesive for joining electronic parts, a one-component adhesive in which a main agent and a curing agent are mixed in advance (see, for example, JP-A-59-142270) is used. And two types of two-component adhesives are mainly used. However, these adhesives have the following problems.

[0005]

Most of the one-part adhesives are low-temperature and quick-curing, and have a pot life at room temperature (the time during which the adhesive can be used, the so-called pot life). It is getting shorter. For this reason, it is necessary to keep most of the one-component adhesive in a frozen state, prevent the reaction between the main agent and the curing agent by the time of use, and extend the pot life. The pot life of the adhesive at room temperature is about one day, and the pot life can be extended to only about two or three months even if it is stored frozen. Therefore, it is difficult to store the adhesive for a long time. In addition, when using an adhesive stored in a frozen state, the adhesive must be returned to room temperature, resulting in poor workability. Further, the adhesive absorbs moisture in the outside air when returning to room temperature, so that its properties are deteriorated.

On the other hand, when a two-part adhesive is used, the main agent and the curing agent must be mixed, so that the workability also deteriorates.

To solve the above problems, Japanese Patent Application Laid-Open No. 10-50142 discloses (A) an epoxy resin as a main agent, (B) a reaction product of an imidazole and an epoxy resin as a curing agent, and a borate ester. And a phenolic resin, and (C) a conductive resin paste composition containing a conductive filler as an additive.
In this composition, the boric acid ester contained as a curing agent and the phenol resin suppress the reaction between the imidazoles and the epoxy resin at room temperature, so that the polymerization curing of the epoxy resin as the main agent is delayed, so that the pot life is reduced. On the other hand, the epoxy resin as the main agent is rapidly polymerized and cured by the curing agent during heating while being heated.

However, in the conductive resin paste composition, it is necessary to add a special component such as a boric acid ester or a phenol resin in order to suppress polymerization and curing of the epoxy resin at room temperature. For this reason, preparation of the composition is not only time-consuming but also cost-effective.

The present invention has been conceived under such circumstances, and does not impair the curing speed during heating and does not add a special component for extending the pot life. Another object of the present invention is to provide an adhesive which can be stored at room temperature for a long period of time.

[0010]

Means for Solving the Problems To solve the above problems, the present invention takes the following technical means.

That is, according to the present invention, a curing agent,
A one-part adhesive containing a main agent that is thermally cured by reacting with the curing agent, wherein the curing agent is contained as solid particles of imidazoles. Is done.

In the adhesive having the above structure, imidazoles contained as solid particles do not melt into the main agent at room temperature. Therefore, when stored at room temperature, only the surface of the imidazole solid particles reacts with the main agent, and the inside does not react with the main agent. As a result, at room temperature, the viscosity of the adhesive hardly increases, the pot life becomes longer, and the adhesive can be stored for a long time. In addition, there is no need to add a special component for suppressing the curing reaction at room temperature.

The imidazoles contained as solid particles preferably have a melting point of 50 to 300 ° C. This is because by setting the melting point to 50 ° C. or more of imidazoles, melting at room temperature is surely suppressed and the pot life can be extended. In addition, when an imidazole having a melting point of more than 300 ° C. is used when the semiconductor chip is used as an adhesive when bonding the semiconductor chip to the substrate, heat of more than 300 ° C. is applied when the semiconductor chip and the substrate are bonded. Because of the necessity, the semiconductor chip and the substrate may be damaged. For this reason, it is preferable to use imidazoles having a melting point of 50 to 300 ° C.

The particle size of the solid particles of the curing agent is set, for example, to 0.1 to 200 μm. The particle size of the hardener solid particles has a close relationship with the pot life and the curing speed. If the particle size is unduly small, the pot life will be shortened unduly, and if the particle size is unduly large, the hardening during heating will occur. It is preferable to use imidazoles having a particle size in the above range because the speed is unduly slow.

[0015] Preferably, a curing accelerator for accelerating the curing of the main component (most commonly epoxy resin) may be contained.

Preferably, the composition may further contain a conductive filler. As the conductive filler, for example, gold,
Metal particles such as silver, copper, nickel, iron, aluminum, and stainless steel, and particles obtained by coating these metal particles with another metal may be used. Further, a metal capsule may be used as a microcapsule type in which metal particles are coated with an insulating resin such as an epoxy resin so that the conductive filler is uniformly dispersed in the base material.

In addition, an inorganic filler such as alumina, silica or aluminum nitride may be added for the purpose of adjusting the coefficient of thermal expansion, and a viscosity modifier such as liquid acrylic may be used for the purpose of adjusting the viscosity. It may be added.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the adhesive of the present invention will be described with reference to the accompanying drawings, but the present invention is not limited to the embodiment.

FIG. 1 is a sectional view showing an adhesive according to an embodiment of the present invention. As shown in FIG.
It is composed of a main agent 1, a curing agent 2, and an inorganic filler 3,
For example, it is stored and stored in the container 10. In the preservation state of the adhesive A, the solid particles of the hardener 2 and the solid particles of the inorganic filler 3 are dispersed and held in the main agent 1 serving as a matrix. When an electronic component such as a semiconductor chip (not shown) is joined to a substrate (not shown) using the adhesive A, an appropriate amount of the adhesive A is applied to the joint, and the solid particles are heated. What is necessary is just to melt | dissolve the hardening agent 2 of a shape, and to make it react with the main agent 1.

As the main agent 1, an epoxy resin is generally used. Epoxy resin has excellent adhesion,
Since the balance between heat resistance and mechanical properties is good, it is suitable as the main agent 1 of the adhesive A.

The curing agent 2 has, for example, a melting point of 50 to 300.
Solid particles of imidazoles at 0 ° C are preferably used.
Solid particles of imidazoles having a melting point in the above range,
Since it does not melt at room temperature, the main agent 1 reacts only with the solid particle surface of the curing agent 2. Therefore, the main agent 1
There is almost no increase in the viscosity of the adhesive A due to the reaction of the adhesive A with the curing agent 2 even at room temperature. For this reason, the pot life of the adhesive A becomes longer, and long-term storage at room temperature becomes possible.

The average particle size of the curing agent 2 is, for example, 0.1 to 200 μm, preferably 0.1 to 100 μm.
In particular, it is set to 0.1 to 10 μm. If the particle size of the solid particles is unduly small, the pot life becomes unduly short, and if the particle size is unduly large, the curing speed during heating becomes unduly slow, so the particle size is preferably set within the above range. It is.

The imidazoles preferably used as the curing agent 2 include, for example, 2-heptadecyl imidazole and 2,4-diamino-6- (2'-methyl-imidazolyl- (1 '))-ethyl- S-triazine, 2-phenylimidazole, 2-undecylimidazole, 2,4-diamino-6- (2′-undecylimidazolyl) -ethyl-S-triazine, 2-phenyl-4-methylimidazole, 2-ethyl -4-methylimidazole, 2-methylimidazole and the like. These may be used alone or in combination of two or more. The amount of the curing agent 2 added is 10
The amount is preferably 1 to 15 parts by weight with respect to 0 parts by weight.

Examples of the inorganic filler 3 include powders of inorganic compounds such as alumina, silica, and aluminum aluminum. These inorganic compound powders may be used alone or in combination. The inorganic filler 3 is added for the purpose of reducing the thermal expansion property of the adhesive A. That is, for example, when joining materials having low thermal expansion, such as a semiconductor chip and a substrate, if the thermal expansion of the adhesive A is too large, it is difficult to achieve a bonding state that is stabilized against temperature changes. That's why.

The average particle size and the amount of the inorganic filler 3 to be determined should be determined according to the thermal expansion to be achieved. However, when the average particle size is unduly large or the amount of the inorganic filler 3 is unduly large. Since the main agent 1 cannot wet all of the inorganic filler 3 and the adhesive A is hard to be in a liquid state, for example, the average particle diameter is 0.01 to 40 μm, and the amount added to 100 parts by weight of the main agent 1 is 1 to 1. Preferably it is 300 parts by weight.

Although a small amount of impurity ions may be contained in the adhesive A, the concentration of the impurity ions is set to 50 pp so as not to lower the performance as an adhesive.
m or less. The impurity ions that may be contained in the adhesive A include sodium ions (N
a ⁺ ), potassium ion (K ⁺ ), chlorine ion (C
l ^-), and the like.

Then, in order to accelerate the polymerization and curing of the base material 1, the adhesive A may be contained by containing a curing accelerator. As the curing accelerator, imidazoles are used, and the average particle size is preferably 0.01 to 300 μm.

In order to adjust the viscosity of the adhesive A,
A viscosity modifier such as liquid acrylic may be added.

Of course, in addition to the above-described components, a conductive filler may be further added to form a conductive adhesive. Here, the form of the conductive adhesive is schematically shown in FIG.

As the conductive filler 4 used in this case, for example, metal particles such as gold, silver, copper, nickel, iron, aluminum, stainless steel, alloys such as silver-palladium, or other metal particles. Coated with a metal. In order to disperse the conductive filler 4 as uniformly as possible in the base material 1, the conductive filler 4 may be covered with an insulating resin such as an epoxy resin and added as a microcapsule. FIG. 2 shows an example in which the conductive filler 4 is of a microcapsule type.

The adhesive B having such a configuration is shown in FIG.
As shown in (1), for example, it is used when the semiconductor chip 5 is mounted on the substrate 6 in a face-down manner. Specifically, first, in a state where the bump terminals 50 of the semiconductor chip 5 and the corresponding bump terminals 60 provided on the substrate 6 are opposed to each other, the terminal formation surface 51 of the semiconductor chip 5 is
The adhesive B is interposed between the mounting surface 61 and the mounting surface 61. And
By pressing the semiconductor chip 5 against the substrate 6, the conductive filler 4 is selectively interposed between the terminals 50 and 60 facing each other. Then, the force at the time of pressing the semiconductor chip 5 breaks the insulating component 40 of the conductive filler 4 interposed between the terminals 50 and 60, exposing the conductor component 41, and establishing a conductive connection between the terminals 50 and 60. Is done. At this time, since the conductive filler 4 remains covered with the insulating component 40 except for between the terminals 50 and 60,
The insulation other than between the terminals 60 is still secured, and only the terminals 50 and 60 are selectively conducted.
In this state, when the main agent 1 or the curing agent 2 is heated, thermal curing of the main agent 1 starts, and the semiconductor chip 5 and the substrate 6 are joined by the thermally cured main agent 1. Since the thermosetting resin generally tends to shrink during curing, the curing shrinkage causes a greater force to act between the terminals 50 and 60 so as to sandwich the conductive filler 4. In this manner, when the adhesive B is used, the terminals 50 of the semiconductor chip 5 and the terminals 60 of the substrate 6 are reliably electrically connected to each other, and the insulation of other portions is reliably maintained.

The average particle diameter of the conductor portion in the inorganic filler 3 is set to be larger than that of the inorganic filler 3 in the conductive filler 4. For example, the average particle size of the conductor component 41 is 1 to 20.
It is preferred to be in the range of μm. This is because if the average particle size of the inorganic filler 3 becomes unduly large, the inorganic filler 3 may be pinched between the terminal 50 of the semiconductor chip 5 and the terminal 60 of the substrate 6 and may cause a conduction failure. .

The conductive filler 4 in the adhesive B
Is, for example, 1 to 45 vol%. This is because when the proportion of the conductive filler 4 is unduly large, a conductive adhesive in a state of maintaining the graininess cannot be obtained. Also, if the ratio of the conductive filler 4 is unduly small, it may be difficult to selectively conduct only between the terminal 50 of the semiconductor chip 5 and the terminal 60 of the substrate 6.

[0034]

Next, examples of the present invention will be described together with comparative examples.

[0035]

Example 1 In this example, 100 parts by weight of a bisphenol F-type epoxy resin (trade name: EXA830LVP, manufactured by Dainippon Ink Co., Ltd.) was used as a main agent, and solid particulate imidazole (trade name: 2MA-OK) was used as a curing agent. , Shikoku Chemicals Co., Ltd.), 5 parts by weight, alumina fine powder as an inorganic filler (trade name: AO-902, Admatechs Co., Ltd.)
) Was uniformly stirred and mixed with 120 parts by weight to prepare an adhesive. The average particle size of the inorganic filler was 2 μm, and the impurity ions (N
a ^+, K ^+, Cl ^- concentration) was less than 10 ppm. Then, the following test was conducted for this adhesive,
The performance was evaluated.

(Gel time method)
The gel time of the adhesive in this example was measured. In the gel time method, the adhesive is heated to 150 ° C. while the rotor is immersed in the adhesive and rotated, and the time during which the adhesive hardens and the rotor does not move (gel time) is measured. The curability of the adhesive was determined.
The adhesive of this example had a gel time at 150 ° C. of 15 seconds, and was confirmed to be excellent in curability.

(Joint stability after temperature cycle test) Using the adhesive in this embodiment, 128 terminal electrodes (15
A silicon chip having a pitch of 0 μm) and a glass epoxy substrate having 128 connection pads corresponding to the terminal electrodes of the silicon chip were bonded by thermocompression bonding to obtain a sample for a temperature cycle test. 500 samples for such a temperature cycle test were prepared, and each sample was subjected to a temperature cycle test in the range of -55 ° C to 125 ° C. In the temperature cycle test, the sample was first cooled at −55 ° C. for 15 minutes, then raised to room temperature and left for 10 minutes, and further heated to 125 ° C. and heated for 15 minutes to form one cycle. After repeating this cycle 1000 times for each sample, the conduction resistance was measured. In the present embodiment, as a result of measuring the conduction resistance of 6.4 × 10 ⁴ (128 × 500) connection points in 500 samples, at all the connection points,
The increase in resistance after the cycle test was as good as 10% or less of the resistance before the cycle test, and no poor conduction was observed. That is, it was confirmed that the chip and the substrate were stably joined by the adhesive of this example even when the temperature was changed.

(Pot life) The adhesive in this example was left at room temperature for 6 months, and the change with time of the viscosity of the adhesive was measured. Further, according to an infrared absorption spectrum (IR), the peak area of the epoxy group / the peak area of the phenylene at the P-position in the adhesive (a change in the ratio means that the epoxy resin was polymerized and cured by reacting with the curing agent. Do)
The changes were investigated. Table 1 shows the results.

[0039]

[Table 1]

As shown in Table 1, neither the viscosity nor the peak area of the epoxy group / the peak area of the phenylene at the P-position changed significantly after 6 months. Therefore, at room temperature, the epoxy group does not react with imidazoles as a curing agent, and judging from the numerical values in Table 1, the pot life of the adhesive in this example is expected to be one year or more at room temperature. .

(Electrolytic Corrosion Test) FIG. 2 is a schematic structural view showing a comb-shaped pattern electrode used in the electrolytic corrosion test. As shown in the figure, the adhesive in this example was applied to the electrodes 7 and 8 constituting the comb pattern with a gap of 40 μm, and the adhesive was cured by heating at 175 ° C. for 1 minute. . Next, an electrolytic corrosion test was performed at a temperature of 85 ° C., a relative humidity of 85%, and a direct current (DC) of 5 V for 500 hours, and the insulation resistance before and after the test was compared. Table 2 shows the results.

[0042]

[Table 2]

As shown in Table 2, it was confirmed that the electrode coated with the adhesive of the present example did not change much in insulation resistance and had good corrosion resistance. Also, 1
The above-described electrolytic corrosion test was also performed on the electrodes having a comb pattern having a gap of 0 μm and 20 μm.
As in the case of the comb pattern electrode having a gap, 500
The change in insulation resistance after time was not so large, and the corrosion resistance was good.

[0044]

Example 2 In this example, the adhesive of Example 1 was further added with a latent imidazole (trade name: H) as a curing accelerator.
X3921 (manufactured by Asahi Ciba Co., Ltd.) was added, and the other composition was the same as in Example 1. An adhesive was prepared, and the same test as in Example 1 was performed on the obtained adhesive. Gel time, bonding stability after temperature cycle test, pot life,
In each of the electrolytic corrosion tests, the same result as in Example 1 was obtained.

Also, imidazoles such as HX3941, HX3741, HX3722, HX
3742 (all trade names, manufactured by Asahi Ciba Co., Ltd.), PN
Using any of -23, MY-24, and MY-N (all of which are trade names, manufactured by Ajinomoto Co., Inc.), the same results as in Example 1 were obtained.

[0046]

Example 3 In this example, instead of the curing agent (2MA-OK) in Example 1, 2-heptadecyl imidazole (trade name: C17Z) and 2,4-diamino-6- (2 ′) were used, respectively. -Methylimidazolyl- (1 '))-
Ethyl-S-triazine (trade name: 2MZ-A), 2-
Phenylimidazole (trade name: 2PZ-A), 2-undecylimidazole (trade name: C11Z), 2,4-
Diamino-6- (2′-undecylimidazolyl) -ethyl-S-triazine (trade name: C11Z-A), 2-
Phenyl-4-methylimidazole (trade name: 2P4M
Z), 2-ethyl-4-methylimidazole (trade name:
2E4MZ), 2-methylimidazole (trade name: 2M)
Z) Each adhesive was prepared in the same manner as in Example 1 except that solid particulate imidazole (all manufactured by Shikoku Chemicals Co., Ltd.) was used, and the respective adhesives were prepared. Was tested. As a result, the same results as in Example 1 were obtained for all the adhesives in the gel time, the bonding stability after the temperature cycle test, the pot life, and the electrolytic corrosion test.

[0047]

EXAMPLE 4 In this example, the curing accelerators (HX3921, HX3941, HX3741, HX3741) used in Example 2 were used.
X3722, HX3742, PN-23, MY-24,
MY-N) and the curing agent used in Example 3 (C17Z,
2MZ-A, 2PZ-A, C11Z-A, C11Z, 2
P4MZ, 2E4MZ, 2MZ) to prepare adhesives. Other compositions were the same as in Example 1, and the same test as in Example 1 was performed on the obtained adhesive. In each of the gel time method, the bonding stability after the temperature cycle test, the pot life, and the electrolytic corrosion test, the same results as in Example 1 were obtained.

[0048]

Embodiment 5 In the present embodiment, instead of the inorganic filler (alumina powder) in Embodiment 1, aluminum nitride coated with Si (trade name: SCAN ^* 70, manufactured by DuPont)
Was used. An adhesive was prepared with the other composition being the same as in Example 1, and the same test as in Example 1 was performed on the obtained adhesive. Gel time, bonding stability after temperature cycle test, pot life, in any of the electrolytic corrosion test,
A result similar to that of Example 1 was obtained.

[0049]

Embodiment 6 In this embodiment, an adhesive was produced by changing the amount of the inorganic filler (alumina powder) added in Embodiment 1. Specifically, 1 part by weight, 100 parts by weight, and 300 parts by weight of an additive were added to 100 parts by weight of the main agent, an adhesive was prepared in the same manner as in Example 1, and an adhesive was prepared. The same test as in Example 1 was performed. Gel time, bonding stability after temperature cycle test, pot life,
In each of the electrolytic corrosion tests, the same result as in Example 1 was obtained.

[0050]

Example 7 In this example, an adhesive was prepared in the same manner as in Example 1 except that the impurity ion concentration in Example 1 was set to 20 ppm or less, and the obtained adhesive was tested in the same manner as in Example 1. Was performed. As a result, the gel time method,
The same results as in Example 1 were obtained in any of the bonding stability, the pot life, and the electrolytic corrosion test after the temperature cycle test.

[0051]

Example 8 In this example, 100 parts by weight of a bisphenol F type epoxy resin (trade name: EXA830LVP, manufactured by Dainippon Ink Co., Ltd.) was used as a main agent, and solid particulate imidazole (trade name: 2MA-OK) was used as a curing agent. , Shikoku Chemicals Co., Ltd.), 5 parts by weight, alumina fine powder as an inorganic filler (trade name: AO-902, Admatechs Co., Ltd.)
Of a microcapsule-type conductive filler obtained by coating the surface of an Ag particle (conductor component) having an average particle diameter of 7 μm with an epoxy resin so that the volume ratio in the entire adhesive becomes 15 vol%. Stir and mix into
An adhesive was prepared. The average particle size of the inorganic filler is 2
μm. In addition, the conductive filler is used as a solvent for 6.
An oil in which Ag particles having an average particle diameter of 7 μm and an epoxy resin (trade name: Epicoat 828, manufactured by Yuka Shell Epoxy Co., Ltd.) are mixed in 0 ml such that the volume ratio thereof is 7:30. The phase is formed by stirring and dispersing in an aqueous phase in which 15 g of tetraethylenepentamine as a curing agent is dissolved in 400 ml of water to form a suspension, and heating the suspension at 60 ° C. for 120 minutes with stirring.

Using the same test as in Example 1, the adhesive was evaluated for gel time, bonding stability after a temperature cycle test, pot life, and electrolytic corrosion.

As a result of the test by the gel time method, 150 ° C.
Was 15 seconds, and it was confirmed that the curability was excellent.

As a result of the temperature cycle test, 6.4 × 10 ⁴ (= 128 × 50) in 500 samples was obtained.
0) As a result of measuring the conduction resistance of the connection points, at all the connection points, the resistance increase after the cycle test was as good as 10% or less of the resistance before the cycle test, and no conduction failure was observed. Was. That is, it was confirmed that the chip and the substrate were stably joined by the adhesive of this example even when the temperature was changed.

Table 3 shows the pot life test results.
The viscosity and the epoxy group peak area / P-position phenylene peak area did not change significantly after one month of standing at room temperature or after one year of freezing and storage. Therefore, it is presumed that the epoxy group hardly reacts with imidazoles as a curing agent, and the pot life is prolonged not only when the adhesive of the present embodiment is stored in a frozen state but also when left at room temperature.

[0056]

[Table 3]

The results of the electrolytic corrosion test are shown in Table 4. The electrode coated with the adhesive of the present example showed a very small change in the insulation resistance even in the 500-hour electrolytic corrosion test, and showed good corrosion resistance. It was confirmed that there was.

[0058]

[Table 4]

[0059]

Example 9 In this example, an adhesive was prepared in the same manner as in Example 8 except that no curing accelerator was added, and the same test as in Example 1 was performed on the obtained adhesive. In all of the gel time, the bonding stability after the temperature cycle test, the pot life, and the electrolytic corrosion test, the same results as in Example 8 were obtained.

[0060]

Embodiment 10 In this embodiment, instead of the curing accelerator (trade name: HX3921, manufactured by Asahi Chiba KK) in Example 8, imidazoles such as HX3941 and HX374 are used.
1, HX3722, HX3742 (all trade names, manufactured by Asahi Chiba Co., Ltd.), PN-23, MY-24, MY-N
An adhesive was prepared in the same manner as in Example 8 using each of the above (trade names, manufactured by Ajinomoto Co., Inc.), and the same test as in Example 1 was performed for each obtained adhesive.
For each adhesive, gel time, bonding stability after temperature cycle test, pot life, and electrolytic corrosion test,
A result similar to that of Example 8 was obtained.

[0061]

Embodiment 11 In this embodiment, 2-heptadecylimidazole (trade name: C17Z) and 2,4-diamino-6- (2 ′) are used instead of the curing agent (2MA-OK) in Embodiment 8. -Methylimidazolyl- (1 '))-
Ethyl-S-triazine (trade name: 2MZ-A), 2-
Phenylimidazole (trade name: 2PZ-A), 2-undecylimidazole (trade name: C11Z), 2,4-
Diamino-6- (2′-undecylimidazole) -ethyl-S-triazine (trade name: C11Z-A), 2-
Phenyl-4-methylimidazole (trade name: 2P4M
Z), 2-ethyl-4-methylimidazole (trade name:
2E4MZ), 2-methylimidazole (trade name: 2M)
Z) Each adhesive was prepared in the same manner as in Example 8 except that solid particulate imidazole (all of which were manufactured by Shikoku Chemicals Co., Ltd.) was used. Was tested. As a result, the same results as in Example 8 were obtained for all the adhesives in any of the gel time, the bonding stability after the temperature cycle test, the pot life, and the electrolytic corrosion test.

[0062]

Example 12 In this example, the curing accelerators (HX3921, HX3941, HX374) used in Example 10 were used.
1, HX3722, HX3742, PN-23, MY-
24, MY-N) and the curing agent (C
17Z, 2MZ-A, 2PZ-A, C11Z-A, C1
1Z, 2P4MZ, 2E4MZ, and 2MZ), and the same test as in Example 1 was performed on the adhesive obtained in the same manner as in Example 8 except for the other compositions. In each of the gel time method, the bonding stability after the temperature cycle test, the pot life, and the electrolytic corrosion test, the same results as in Example 8 were obtained.

[0063]

Example 13 In this example, an adhesive was used in the same manner as in Example 8, except that solid imidazole having a melting point of about 50 ° C. (trade name: 2MZ-CN, manufactured by Shikoku Chemicals Co., Ltd.) was used. The same test as in Example 1 was performed on the prepared and obtained adhesive. Gel time, bonding stability after temperature cycle test, pot life, in any of the electrolytic corrosion test,
A result similar to that of Example 8 was obtained.

[0064]

Example 14 In this example, silica powder (trade name: SE-05, manufactured by Admatex Co., Ltd.) was used in place of the alumina powder as the inorganic filler used in Example 8. An adhesive was prepared in the same manner as in Example 8, and the same test as in Example 1 was performed on the obtained adhesive.
In all of the gel time, the bonding stability after the temperature cycle test, the pot life, and the electrolytic corrosion test, the same results as in Example 8 were obtained.

[0065]

Embodiment 15 In this embodiment, an adhesive was produced by changing the amount of alumina powder as an inorganic filler in Embodiment 8. Specifically, 1.5 parts by weight (0.5 wt%) of alumina and 3 parts by weight (1.0 wt.
%) And 300 parts by weight (100 wt%), and the other composition was the same as in Example 8, an adhesive was produced. The same test as in Example 1 was performed on the obtained adhesive. In all of the gel time, the bonding stability after the temperature cycle test, the pot life, and the electrolytic corrosion test, the same results as in Example 8 were obtained.

[0066]

Example 16 In this example, an adhesive was produced in the same manner as in Example 8 except that the liquid acrylic was removed from the adhesive in Example 8, and the obtained adhesive was tested in the same manner as in Example 1. Was performed. Gel time, bonding stability after temperature cycle test, pot life, in any of the electrolytic corrosion test,
A result similar to that of Example 8 was obtained.

[0067]

Embodiment 17 In this embodiment, an adhesive was produced by changing the amount of the conductive filler added in Embodiment 8. Specifically, the volume ratio in the entire adhesive is 1 vol%, 20 vol.
An adhesive having the same composition as in Example 8 was prepared except that the vol% was changed to 45 vol%, and the same test as in Example 1 was performed for each of the obtained adhesives. In all of the gel time, the bonding stability after the temperature cycle test, the pot life, and the electrolytic corrosion test, the same results as in Example 8 were obtained.

[0068]

Comparative Example 1 In this comparative example, an adhesive was produced under the same conditions as in Example 1 except that the alumina fine powder as the inorganic filler in Example 1 was not used at all, and the obtained adhesive was evaluated. The same test as in Example 1 was performed. As a result, for gel time, pot life, and electrolytic corrosion test,
Although the same results as in Example 1 were obtained, the bonding stability after the temperature cycle test was 1 out of 500 samples.
Poor conduction was found in 16 samples. From this,
It was confirmed that it is preferable to add an inorganic filler such as alumina in order to secure the bonding stability.

[0069]

Comparative Example 2 In this comparative example, an adhesive was prepared by changing the amount of alumina powder as an inorganic filler in Example 1 to be added. Specifically, 310 parts by weight of the inorganic filler was added to 100 parts by weight of the main ingredient. However, since the amount of the alumina powder added was too large, some alumina powders did not wet with the main ingredient.
The adhesive did not go liquid. From this, it was confirmed that when the content of the inorganic filler such as alumina was excessively increased, the preparation of the adhesive became difficult.

[0070]

Comparative Example 3 In this comparative example, the impurity ion concentration was 50 pp.
An adhesive was prepared in the same manner as in Example 1 except that the value was m or more, and the same test as in Example 1 was performed on the obtained adhesive. The same results as in Example 1 were obtained for the gel time, the bonding stability after the temperature cycle test, and the pot life. However, a short circuit occurred after 100 hours in the electrolytic corrosion test because of a large amount of impurity ions.

[0071]

Comparative Example 4 In this comparative example, a solid imidazole having a melting point of 45 ° C. (trade name: IB2PZ, Shikoku Chemicals Co., Ltd.)
An adhesive was prepared in the same manner as in Example 8 except that the adhesive was used, and the same test as in Example 1 was performed on the obtained adhesive. In all of the gel time, the bonding stability after the temperature cycle test, and the electrolytic corrosion test, the same results as in Example 8 were obtained, but the viscosity was doubled after one month, and the pot life was poor. Further, when solid imidazole having a melting point of 300 ° C. or more is used, it is necessary to raise the temperature of the junction between the semiconductor chip and the substrate, which may cause damage to the substrate and the like. These facts and Example 13
From that solid imidazole as a curing agent has a melting point of 50
A temperature of about 300 ° C. is considered appropriate.

[0072]

Comparative Example 5 In this comparative example, the addition amount of the alumina powder as the inorganic filler in Example 8 was 310 parts by weight (110 wt%) relative to 100 parts by weight of the main agent, but the addition amount of the alumina powder was too large. The adhesive did not become liquid because some alumina powder did not wet with the main agent. From this, it was confirmed that when the content of the additive such as alumina was excessively increased, the preparation of the adhesive became difficult.

[0073]

Comparative Example 6 In this comparative example, the average particle size of the conductive component of the microcapsule type conductive filler in Example 8 was set to 1 μm, and the average particle size of the alumina powder as the inorganic filler was set to 5 μm. An adhesive was prepared in the same manner as in Example 8. As for the gel time, the pot life, and the electrolytic corrosion test, the same results as in Example 8 were obtained. However,
After the temperature cycle test, 385 out of 500 sheets had poor conduction after the sample was produced. From this, it is presumed that the particle size of the conductive particles needs to be larger than that of the inorganic filler.

[0074]

Comparative Example 7 In this comparative example, an adhesive was produced by changing the amount of the conductive filler added in Example 8. Specifically, the volume ratio in the entire adhesive is 0.5 vol%, 5 vol%,
An adhesive was prepared with the same composition as in Example 8 except that the content was 0 vol%, and the same test as in Example 1 was performed for each of the obtained adhesives. With respect to the adhesive having an addition amount of 0.5 vol%, conduction failure occurred after the preparation of the sample for the temperature cycle test. In addition, the adhesive could not be prepared for the 50 vol% adhesive because the conductive filler did not completely fit into the adhesive.

[0075]

As described above, the adhesive for bonding electronic parts of the present invention contains solid particles of imidazoles having a melting point of 50 to 300 ° C. as a curing agent, so that the pot life at room temperature becomes longer, Long-term storage at room temperature becomes possible.
In addition, since the curing speed at the time of heating does not decrease and remains large, the workability is high. The same effect can be obtained with an adhesive to which a conductive filler has been added.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a stored state of an adhesive according to the present invention.

FIG. 2 is a sectional view showing a storage state of another adhesive according to the present invention.

FIG. 3 is a sectional view showing a state of use of the adhesive shown in FIG. 2;

FIG. 4 is a schematic configuration diagram showing a comb-shaped pattern electrode used for an electrolytic corrosion test.

[Explanation of symbols]

 A, B Adhesives for bonding electronic parts 1 Main agent 2 Hardener 3 Inorganic filler 4 Conductive filler

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Eiji Tokuhira 4-1-1, Kamikodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Nobuhiro Imaizumi 4-1-1, Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa No. 1 Inside Fujitsu Limited (72) Tomohisa Yagi 4-1-1 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture 1-1 Inside Fujitsu Limited (72) Makoto Usui 4-chome, Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture No. 1 in Fujitsu Limited

Claims (3)

[Claims] 1. A one-part adhesive containing a curing agent and a main agent which is thermally cured by reacting with the curing agent, wherein the curing agent is contained as imidazole solid particles. Adhesive characterized by the following. 2. The adhesive according to claim 1, wherein a hardening accelerator for accelerating the hardening of the main agent is further mixed as solid particles, and the main agent is an epoxy resin. 3. The adhesive according to claim 1, further comprising conductive particles.