JP5254265B2 - Resin composition for sealing electronic parts and lid for sealing electronic parts using the same - Google Patents

Description

  The present invention relates to a resin composition for encapsulating an electronic component that is used when an electronic component element such as a solid-state imaging device, a crystal resonator, or a laser pickup is housed in a hollow package and hermetically sealed, and an electronic component using the same The present invention relates to a sealing lid.

Conventionally, electronic component elements such as solid-state imaging devices and crystal resonators are housed in a package such as ceramic, and this is covered with a resin composition for sealing electronic components made of an organic adhesive or an inorganic adhesive. The material is hermetically sealed.
That is, after the electronic component element is housed in the package body, the resin composition for sealing the electronic component is interposed between the package body and the lid material, and the package body and the lid material are heated while being pressed to apply the resin. The composition is melted, and the package body and the lid are bonded and hermetically sealed.

Conventionally, a semi-cured adhesive mainly composed of an epoxy resin has been used as a resin composition for sealing an electronic component (see, for example, Patent Document 1 and Patent Document 2). Such a conventional semi-cured adhesive requires a curing temperature of 150 ° C. or more, and a curing time of 3 hours or more.
However, in recent years, the resin composition for electronic component sealing that seals and seals the package body for a solid-state imaging device or a semiconductor laser and a lid material is caused by problems of heat resistance of the substrate or heat resistance of the device and outgas. Due to the problem of contamination, there is a demand for a curing temperature that is low and that curing can be completed in a short time and has low outgas.
The low-temperature and short-time curing can be solved by using a curing agent or a curing accelerator whose reaction proceeds at a lower temperature. However, since this method has a high curing rate, the semi-cured state of the resin composition cannot be controlled and maintained, and cannot be used as the sealing lid material for electronic parts.
On the other hand, an ultraviolet curable adhesive may be used as an airtight sealing adhesive that satisfies the above requirements. However, under the present circumstances, an ultraviolet curable adhesive that can be fully satisfied has not yet been obtained due to the problem of airtightness between the package body and the lid.

JP-A-1-310565 JP-A-8-143646

  The present invention has been made in consideration of the above circumstances, and the package body for housing the electronic component element and the lid member can be hermetically sealed with sufficient reliability, while being able to be semi-cured and maintained and stored. An object of the present invention is to provide an electronic component sealing resin composition that can be cured at a lower outgas, lower temperature, and shorter time than conventional ones, and an electronic component sealing lid using the same.

The resin composition for encapsulating electronic components of the present invention comprises a thermosetting resin composed of an epoxy resin , a semi-curing agent composed of an aromatic amine or an alicyclic amine, an imidazole-based adduct-type latent curing agent , boric acid It contains a stabilizer comprising an ester compound .
Further, it is preferable to contain a reaction accelerator consisting of a further in e elastomer and imidazoles.
The electronic component sealing lid is characterized in that the resin composition for sealing an electronic component is formed in an arbitrary shape on a substrate in a semi-cured state.

  According to the present invention, it is possible to hermetically seal the package main body and the lid member for housing the electronic component element with sufficient reliability, and while being capable of semi-curing control and maintenance storage, it is lower than the conventional one. It is possible to provide an electronic component sealing resin composition that can be cured in an outgas, low temperature, and short time, and an electronic component sealing lid using the same.

It is explanatory drawing which showed the electronic component sealing lid body of this invention. It is explanatory drawing which showed another electronic component sealing lid body of this invention. It is explanatory drawing which showed another electronic component sealing lid body of this invention. It is explanatory drawing which showed another electronic component sealing lid body of this invention.

Hereinafter, the present invention will be described in detail.
Examples of the thermosetting resin in the present invention include phenol resin, furan resin, epoxy resin, unsaturated polyester resin, polyimide resin, urea resin, and melamine resin. Among these, an epoxy resin is particularly preferable. As the epoxy resin referred to in the present invention, one or two or more liquid epoxy resins selected from bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, and glycidylamine are preferable.
Among these resins, those that are liquid at room temperature are preferable because they are easily applied to a substrate such as a package body or a lid. However, solid epoxy resins can be used, for example, by mixing with liquid epoxy resins or by adding a reactive diluent.
In addition, if the viscosity of the resin used is lowered by increasing the temperature at the time of application, a solid epoxy resin can be used at room temperature, and solid epoxy can be used as a liquid curing agent or reactive diluent. A resin can be dispersed and used.
It is preferable that content of a thermosetting resin is 1-80 mass% in the resin composition for electronic component sealing. When the amount of the thermosetting resin is less than 1% by mass, sufficient heat resistance may not be obtained. When the amount is more than 80% by mass, the internal stress becomes excessively brittle, resulting in poor heat resistance reliability and poor workability. There is a case. Further, the content of the thermosetting resin is preferably 1 to 60% by mass, and by setting the content to 1 to 60% by mass, a product having a relatively low internal stress and a high glass transition temperature can be obtained. A reliable resin composition can be obtained.

In the present invention, another semi-curing agent different from the latent curing agent is contained for the purpose of semi-curing the epoxy resin component. The latent curing agent must not be activated during the semi-curing, and is limited to a semi-curing agent that can be used in a temperature range that maintains the potential. As such a semi-curing agent, aromatic amines or alicyclic amines such as diaminodiphenylmethane and diaminodiphenylsulfone are preferable, and aromatic amines and derivatives thereof are preferably used in order to achieve semi-curing at a lower temperature.
The content ratio of the semi-curing agent to the thermosetting resin is preferably in the range of an equivalent ratio of 0.2 to 1.0 from the viewpoint of heat resistance and workability. If the equivalent ratio is less than 0.2, it takes time to obtain a semi-cured state, and if it is more than 1.0, it is difficult to obtain a semi-cured state.

  The latent curing agent as used in the present invention completely cures the thermosetting resin when heated. As the latent curing agent, one or a plurality of various latent curing agents can be selected and used. In particular, amine-based adduct-type latent curing agents or imidazole-based adduct-type latent curing agents are preferable, and examples thereof include latent amine compounds and modified amines such as amine adducts. The modified amines include a core-shell type curing agent (microcapsule) in which the surface of the core of an amine compound or amine adducts is surrounded by a shell of a modified amine (such as surface adduct), and these are mixed with an epoxy resin. A masterbatch-type curing agent in a heated state is included.

  As the stabilizer referred to in the present invention, an alkyl or aryl ester of boric acid is used alone or in combination with a phenol resin. The boric acid ester is an alkyl or aryl ester of boric acid, specifically, trimethyl borate, triethyl borate, tributyl borate, triphenyl borate and the like. In the present invention, the boric acid ester content is preferably in the range of 5.0 to 15.0 parts by mass with respect to 100 parts by mass of the thermosetting resin from the viewpoint of reactivity and physical properties. In particular, if the blending amount is less than this, the effect of improving the storage stability cannot be obtained, and if this amount is exceeded, the curing reactivity may be extremely lowered, or conversely, the storage stability may be deteriorated.

  In the present invention, it is preferable to contain an elastomer for the purpose of relieving the adhesiveness and adhesion to the substrate and the stress generated between the substrates at the time of adhesion. The elastomer is not particularly defined, but for example, isoprene rubber, butadiene rubber, styrene butadiene rubber, chloroprene rubber, nitrile rubber, butyl rubber, ethylene-propylene rubber, acrylic rubber, silicone rubber, fluorine rubber, urethane rubber, polysulfide rubber, etc. Styrene-type TPE, olefin-type TPE, urethane-type TPE, ester-type TPE, amide-type TPE, natural rubber-type TPE, polyvinyl chloride (PVC) type as thermoplastic elastomers and thermoplastic elastomers (hereinafter abbreviated as TPE) Mention may be made of TPE. These elastomers can be used alone or in combination. In the present invention, the elastomer content is preferably in the range of 5.0 to 15.0 parts by mass with respect to 100 parts by mass of the thermosetting resin in terms of reactivity and physical properties.

The resin composition for sealing an electronic component of the present invention may contain a reactive diluent, a reaction accelerator, a filler, a coupling agent and the like.
As the reactive diluent, it is possible to adjust the viscosity of the resin composition for encapsulating an electronic component, and it does not affect the characteristics of the electronic component element that is gasified and stored when the package is sealed. Anything can be used.
Examples of the reaction accelerator include imidazoles such as 2-ethyl-4-methylimidazole and 2-undecylimidazole, m-phenylrangeamine, diaminodiphenyl ether, and trifluoride for the purpose of curing at high temperature for a short time. Examples include amines such as boron monoethylamine complex salt, triphenylphosphine, carboxylic acid and the like.
Examples of the filler include silica, quartz powder, alumina, calcium carbonate, magnesium oxide, and zinc oxide.
The viscosity of the resin composition for sealing an electronic component in the present invention is preferably liquid at room temperature, and particularly preferably in the range of 1 to 1000000 centipoise at 25 ° C. However, even if it is solid at room temperature, it can be used in the present invention as long as it becomes liquid upon heating.

The lid for sealing an electronic component of the present invention is obtained by forming the above-described resin composition for sealing an electronic component in an arbitrary shape on a substrate in a semi-cured state. The semi-cured state here refers to a state called a B-stage state. This state refers to a state where the reaction proceeds two-dimensionally in the thermosetting resin and the semi-curing agent and exists as a linear high molecular weight substance. While this state is a thermosetting resin, it has the properties of a thermoplastic resin and melts by heating, and reacts with another curing agent at a temperature above a certain temperature, leading to a three-dimensional crosslinking reaction and insoluble and infusible. It becomes a cured product.
The electronic component sealing lid of the present invention is, for example, one in which a rectangular electronic component sealing resin composition 2 having a space inside is formed on a rectangular substrate 1 as shown in FIG. Can be mentioned. Moreover, as shown in FIG. 2, the thing in which the resin composition 2 for circular electronic component sealing which has a space inside was formed on the circular base | substrate 1 can be mentioned. Moreover, as shown in FIG. 3, the thing in which the resin composition 2 for the square-shaped electronic component sealing which does not have a space inside on the square-shaped base | substrate 1 can be mentioned. The substrate referred to in the present invention is not limited to a planar body as shown in FIGS. 1 to 3, but a substrate 1 as shown in FIG. 3 having an electronic component element 3 such as a solid-state imaging device, a crystal resonator, or a laser pickup in a hollow interior. But you can. In FIG. 3, an electronic component sealing resin composition 2 is formed on the frame of the substrate 1.
Examples of the method for forming the resin composition 2 for encapsulating an electronic component on the substrate 1 include a screen printing method and a dispenser method. Any method may be used as long as the dimensional accuracy and the coating shape can be controlled.
Hereinafter, the present invention will be described based on examples.

[ Reference Examples 1-2, Example 3 and Comparative Examples 1-2]
After the materials shown in Table 1 were kneaded by a three-roll mill, vacuum degassing was performed to obtain an electronic component sealing resin composition of the present invention and a comparative electronic component sealing resin composition. In addition, the compounding quantity of Table 1 shows a mass part.

Specific compounds of the materials in Table 1 are as follows.
・ Epoxy resin: Bisphenol A type epoxy resin ・ Aromatic amine: Diaminodiphenylmethane ・ Modified amine: Urea type adduct modified amine ・ Amine adduct: Epoxy amine adduct ・ Imidazole adduct: Epoxy imidazole adduct ・ Boric acid ester compound: Epoxy phenol borate ester Compound-Imidazole A: 2,4-Diamino-6- [2'-methylimidazolyl- (1 ')]-ethyl-S-triazine isocyanuric acid adduct-Imidazole B: 2-ethyl-4-methylimidazole-Silane Coupling agent: 3-glycidoxypropyltrimethoxysilane Elastomer: Polyisoprene maleic anhydride adduct Filler: Silica

Table 2 shows the results of testing the semi-curing control, the semi-cured state stability, and the complete curing temperature of the electronic component sealing resin composition shown in Table 1.
(A) Semi-curing control ○ indicates that semi-curing control is possible.
X indicates that semi-curing cannot be controlled and complete curing occurs.
(B) Stability of semi-cured state ○ indicates that the semi-cured state can be stably maintained at room temperature.
Δ indicates that although the semi-cured state is maintained at room temperature, the reaction proceeds and the long-term stability is poor.
In Table 2, Reference Example 1 and Reference Example 2 are examples in which the latent curing agent was used alone. Although Reference Example 1 and Reference Example 2 are capable of controlling semi-curing and reducing the temperature of complete curing, they are inferior in stability in a semi-cured state as compared with Example 3.
Example 3 is an example in which a stabilizer is added in addition to the latent curing agent. In Example 3, good results were obtained for both the semi-curing control and the stability of the semi-cured state. Moreover, it was confirmed that the complete curing temperature is low and curing can be performed at a low temperature.
Comparative Example 1 is excellent in semi-curing control and stability, but high-temperature heating is necessary for complete curing. Comparative Example 2 is an example using an imidazole system in which the reaction proceeds at a lower temperature in the complete curing process, and although it is possible to lower the temperature of complete curing, semi-curing control is impossible.

  Next, a borosilicate glass and an alumina ceramic cap (6.34 × 6.24 mm, t: 1.5 mm) were used as a hollow package evaluation for Example 3. The resin composition for encapsulating electronic components of Example 3 was applied to the peripheral portion of the alumina ceramic cap to a width of 0.5 mm, dried by heating and semi-cured to obtain the lid for encapsulating electronic components of the present invention. It was. The lid was mounted on borosilicate glass and heated at 90 ° C. for 1 hour while applying a load of 2 kg to completely cure the resin composition, and hermetically sealed. Similarly, a lid for sealing an electronic component was produced for Comparative Example 1 and hermetically sealed by heating at 110 ° C. for 30 minutes and then at 150 ° C. for 1 hour.

The airtightness of the sealed package is confirmed by microscopic appearance inspection, gross leak test and helium leak test. After confirming that these packages are airtightly sealed, an adhesive strength test and a reliability test are performed. went. A shear force test was performed as an adhesion test, and a reflow test, a high temperature test, a low temperature test, a high temperature and high humidity test, and a thermal shock test were performed as reliability evaluations, and the airtightness after each reliability test was evaluated. The results are shown in Table 3.
Each inspection and each test is as described below.
(1) Microscope appearance inspection When an electronic component element is housed in a hollow package and hermetically sealed, a force that causes internal air to escape to the outside due to an increase in internal pressure of the package due to heating acts, and this force is applied to the resin sealing surface. Part or complete penetration of the air layer may occur. In this state, the airtightness of the package is inferior, and sufficient reliability cannot be obtained. ○ indicates that there was no air bubble or missing on the sealing surface in the appearance inspection.
(2) Gross Leak Test A hermetically sealed package was immersed in 125 ° C. Fluorinert, and the presence or absence of bubbles was confirmed in 1 minute. ○ indicates that no bubbles were generated.
(3) Helium leak test A hermetically sealed package was pressurized in a helium atmosphere chamber at a pressure of 0.5 Mpa for 30 minutes, then opened and left in the atmosphere for 30 minutes. Helium gas that entered the package was detected during pressure. This is a test in which helium is detected when there is a minute leak. ○ indicates that helium gas was not detected.
(4) Adhesive strength test When the glass part of the hermetically sealed package is fixed, a claw is hooked on an alumina ceramic cap and a tensile load is applied (shear) in the horizontal direction at a speed of 50 mm / min. The force was determined as the adhesive strength.

(5) Reflow test Holding the hermetically sealed package in a 260 ° C. reflow bath for 30 seconds was performed three times, and then the state of the package was observed. ○ indicates that no bubbles were generated in the gross leak test after reflow.
(6) High temperature test The hermetically sealed package was left in a 120 ° C. tank for 1000 hours, and then the state of the package was observed. ○ indicates that no bubbles were generated in the gross leak test after the high temperature test.
(7) Low temperature test The hermetically sealed package was left in a -40 ° C bath for 1000 hours, and then the state of the package was observed. ○ indicates that no bubbles were generated in the gross leak test after the low temperature test.
(8) High-temperature and high-humidity test The hermetically sealed package was left in an 85 ° C., 85% tank for 1000 hours, and then the state of the package was observed. ○ indicates that no bubbles were generated in the gross leak test after the high temperature and high humidity test. Also, Δ indicates that there was a partial occurrence.
(9) Thermal Shock Test The hermetically sealed package was alternately placed in a 120 ° C. and −40 ° C. bath for 30 minutes each, and this was repeated 1000 times, and the state of the subsequent package was observed. ○ indicates that no bubbles were generated in the gross leak test after the thermal shock test.

  As is apparent from Table 3, in Example 3, which is the resin composition for sealing an electronic component of the present invention, both the airtightness and adhesiveness were practically satisfactory. In the high-temperature and high-humidity test, in Comparative Example 1, a part of the airtightness was insufficient and the adhesive strength was lowered, but in Example 3, the reliability was maintained without any problem. This is presumed to be an effect of improving adhesion and adhesion by containing an elastomer.

Moreover, the outgas property was evaluated from the both surfaces after hardening about the resin composition for electronic component sealing of Example 3 and the comparative example 1 at the time of hardening. The purge and trap GC-MS method was used for the measurement. The outgas at the time of curing was measured at each curing temperature, and the outgas after curing was treated at the curing temperature, and then the outgas under heating at 200 ° C. was measured. The results are shown in Table 4. The measurement conditions are as follows.
Curing outgas measurement conditions: Example 3 is 90 ° C. for 30 minutes, and Comparative Example 1 is 150 ° C. for 30 minutes.

  As shown in Table 4, Example 3 which is a resin composition for encapsulating electronic parts of the present invention has a reduced outgas at the time of curing to 1/3 and an outgas after curing to 1/5 from Comparative Example 1. In addition to the effect of reducing the outgassing due to the lowering of the curing temperature, the results show that the resin composition of the present invention itself has a low outgassing property.

DESCRIPTION OF SYMBOLS 1 Base | substrate 2 Resin composition for electronic component sealing 3 Electronic component element

Claims (4)

It contains a thermosetting resin made of epoxy resin , a semi-curing agent made of aromatic amines or alicyclic amines, an imidazole-based adduct-type latent curing agent , and a stabilizer made of a boric acid ester compound. An electronic component sealing resin composition.   The resin composition for sealing an electronic component according to claim 1, further comprising an elastomer.   The resin composition for sealing an electronic component according to claim 1 or 2, further comprising a reaction accelerator comprising imidazoles. One of the electronic component sealing resin composition for electronic component encapsulation lid, characterized in that it is formed on a substrate in a semi-cured state of claims 1 to 3.

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