JPH0529159B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to an impregnating agent for electronic components used for the purpose of filling small gaps and spaces between electronic components and sealing resin. Problems to be solved by conventional techniques and inventions Conventionally, transistors, diodes, resistors,
Electronic components such as capacitors and capacitors made of compacted ceramic powder are encapsulated with resins such as epoxy resin compositions, but there are usually very small gaps or voids between the encapsulation resin and the electronic components. arise. When such gaps and voids exist, components that degrade the characteristics of electronic components, such as water, Cl ^- , and Na ⁺ , can enter from the outside through these gaps and voids, causing the characteristics of electronic components to deteriorate. get up. For this reason, natural waxes such as carnauba and silicone oil have traditionally been used to fill these gaps and voids. Among them, silicone oil has a low surface tension, so it easily gets into small gaps.
In addition, it is widely used because it contains few impurities such as Cl ^- and Na ⁺ that degrade the characteristics of electronic parts, and has excellent heat resistance. However, recently, in order to increase productivity, when attaching electronic components to a printed circuit board, a process has been adopted in which the electronic components are bonded to the printed circuit board with adhesive in advance, and then immersed in a solder bath to attach the electronic components to the printed circuit board. However, when conventional silicone oil is used, it not only fills the voids and crevices of electronic components, but also creates a slight silicone film on the surface, which has poor adhesion with adhesives. A problem arises in that the adhesive does not adhere to the electronic components and cannot be attached to the printed circuit board. Therefore, it is easy to get into the gaps between electronic components, and Cl ^- ,
There is a need for the development of an impregnating agent for electronic components that has a low content of impurities such as Na ⁺ , has good heat resistance, and has good adhesion to adhesives. The present invention was made in view of the above circumstances, and provides an impregnating agent for electronic components that has excellent impregnation properties, good moisture resistance after impregnation and curing, and good adhesion to adhesives. The purpose is to provide. Means and Action for Solving the Problems In order to achieve the above object, the present inventors have found that silicone coatings on the surfaces of electronic components are the biggest drawback when using silicone-based impregnation agents for electronic components. As a result of intensive studies to improve the problem that the adhesiveness to adhesives becomes extremely weak, we found that using a specific silicone compound containing an acrylic group improves the wettability with adhesives and improves the adhesiveness to adhesives. That is, at 25°C obtained by reacting a silicone compound of the formula (1) described below having an acrylic group in one molecule with an alkoxy group-containing silicone compound of the formula (2) described below. The viscosity
3.5 to 50 centistokes silicone compound,
It has excellent impregnating properties when impregnated into electronic parts, reliably prevents external influences on the electronic parts, and has excellent adhesion to adhesives.As mentioned above, electronic parts impregnated and cured with this silicone compound can be The inventors discovered that electronic components can be reliably held on a printed circuit board, etc., even when they are adhered to a printed circuit board, etc., using a type of adhesive and immersed in a solder bath, leading to the completion of the present invention. . Therefore, the present invention provides an impregnating agent for electronic components that fills small gaps and spaces between electronic components and a sealing resin, wherein the impregnating agent has (A) the following general formula (1) R ¹ _a R ² _b Si(OR ³ ) _4-ab ...(1) (However, in the formula, R ¹ is a monovalent hydrocarbon group containing an acryloxy group or a methacryloxy group, R ² is a substituted or unsubstituted monovalent hydrocarbon group, R ³ is an alkyl group or a hydrogen atom, a is 1 or 2, and b is 0 or 1.) and (B) the following general formula (2) R ⁴ ₂ Si(OR ⁵ ) ₂ ...(2) (However, in the formula, R ⁴ is a substituted or unsubstituted monovalent hydrocarbon group or hydrogen atom, and R ⁵ is a monovalent organic group.) Reaction molar ratio with the organosilicon compound represented by (A)/(B) = 0.1 to 10 reaction products, the viscosity at 25°C is in the range of 3.5 to 50 centistokes, and the content of Na ⁺ and Cl ^- is 10 ppm or less each. The present invention provides an impregnating agent for electronic parts with characteristics. The present invention will be explained in more detail below. Used to obtain the impregnating agent for electronic components of the present invention
As mentioned above, the organosilicon compound of component (A) is represented by the following general formula (1) R ¹ _a R ² _b Si(OR ³ ) _4-ab (1). Here, the (meth)acryloxy group-containing monovalent hydrocarbon group of R ¹ in the above formula is not particularly limited, but for example,

[Formula] (γ-methacryloxypropyl group) and a γ-acryloxypropyl group in which the methyl group of this group is a hydrogen atom can be suitably used. Substituted or unsubstituted monovalent hydrocarbon groups for ^R2 include alkyl groups such as methyl, ethyl, and propyl groups, cycloalkyl groups such as cyclohexyl and cycloheptyl groups, and alkenyl groups such as vinyl and allyl groups. , phenyl groups, aryl groups such as xylyl groups, aralkyl groups such as benzyl groups, and groups in which hydrogen atoms of these groups are partially substituted with halogen atoms, mercapto groups, glycidoxy groups, amino groups, etc. can. Also,
R ³ is a hydrogen atom or an alkyl group, and examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and a butyl group. Specifically, examples of the organosilicon compound of component (A) include γ-methacryloxypropyltriethoxysilane, α-methacryloxypropylmethyldimethoxysilane, γ-methacryloxyvinyldimethoxysilane, etc. . The organosilicon compound of component (A) is not particularly limited, but its viscosity at 25°C is 3.
The range is preferably from 100 centistokes to 100 centistokes, more preferably from 3 to 50 centistokes. If the viscosity of component (A) at 25°C is less than 3 centistokes, it may easily volatilize when this composition is impregnated into electronic parts and cured, whereas if it exceeds 100 centistokes, , the impregnating property may be lowered, so for the purpose of the present invention, it is preferable to set it to 3 to 100 centistokes. In addition, from the viewpoint of moisture resistance of electronic parts, component (A)
The contents of Na ⁺ and Cl ^- are each preferably at most 10 ppm, more preferably at most 2 ppm. When the content of Na ⁺ and Cl ^- exceeds 10 ppm, when the silicone composition of the present invention is applied as an impregnating agent for electronic parts, the characteristics of the electronic parts may deteriorate. Next, as mentioned above, the organosilicon compound as the component (B) to be blended into the composition of the present invention is represented by the following general formula (2) R ⁴ ₂ Si (OR ⁵ ) ₂ ...(2) It is something. Here, R ⁴ is a substituted or unsubstituted monovalent hydrocarbon group, specifically an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a cycloalkyl group such as a cyclohexyl group, a cycloheptyl group, etc. alkenyl groups such as vinyl groups and allyl groups, aryl groups such as phenyl groups and xylyl groups, aralkyl groups such as benzyl groups, or hydrogen atoms of these groups are partially halogen atoms, mercapto groups, glycidoxy groups, or amino groups. Examples include groups substituted with, etc. Further, R ⁵ represents an alkyl group, preferably a lower alkyl group having 1 to 4 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, and the like. Examples of the organic silicon compound of component (B) include dimethyldiethoxysilane, dimethyldimethoxysilane, and phenylmethyldimethoxysilane. Like the organosilicon compound of component (A), the organosilicon compound of component (B) preferably has a viscosity of 3 to 100 centistokes at 25°C, more preferably 3 to 50 centistokes. It's Stokes. If the viscosity at 25°C is less than 3 centistokes, the silicone composition of the present invention obtained by reacting with component (A) may easily volatilize when it is impregnated into electronic parts and cured.
If it exceeds 100 centistokes, impregnating properties may decrease. In addition, from the viewpoint of moisture resistance of electronic parts, component (B)
The contents of Na ⁺ and Cl ^- are each preferably at most 10 ppm, more preferably at most 2 ppm. When the content of Na ⁺ and Cl ^- exceeds 10 ppm,
When impregnated into electronic parts, the characteristics of the electronic parts may deteriorate. The impregnating agent for electronic components of the present invention is obtained by reacting the above-mentioned components (A) and (B). ~100 centistokes, preferably 3
It is necessary to polymerize until the viscosity is in the range of ~50 centistokes, and if the viscosity is less than 3.5 centistokes, the impregnating property will be good, but when impregnating and curing electronic parts, etc. The adhesive properties of the adhesive are reduced. Furthermore, if the viscosity exceeds 50 centistokes, the adhesion with the adhesive will be good, but the impregnation into small gaps will be reduced. Therefore, in order to obtain an impregnating agent for electronic components that has both adhesion and impregnating properties to adhesives, it is particularly important to keep the viscosity within the above range. Here, the reaction between components (A) and (B) in the presence of an acid is a well-known condensation reaction, and polymerization occurs through condensation of the alkoxy groups and hydroxyl groups of components (A) and (B). be. Furthermore, since the impregnating agent for electronic components of the present invention directly contacts the very sensitive parts of electronic components, as can be seen from the usage example described later, the impregnating agent for electronic components (A) and B) Component organosilicon compounds include Na ⁺ , which has a negative effect on electronic components.
Although it is preferable to use a product with as little Na + and Cl ^- as possible, it is important to control Na ⁺ and Cl ^- in the silicone composition of the present invention, which is a reaction product.
Na ⁺ and Cl ^- are each 10 ppm or less,
More preferably it is 5 ppm or less. In addition, 5μm that may be mixed in during the reaction of component (A) and (B).
The above solid impurities are preferably 1 mg or less, more preferably 0.01 mg in 100 g of the present impregnating agent.
It is as follows. Moreover, the reaction ratio of component (A) and component (B) is (A)/(B)=0.1-10 in molar ratio, preferably 0.3-5. If this reaction ratio is less than 0.1, the viscosity may increase significantly, and if it exceeds 10, the volatile content during curing may increase and the moisture resistance may decrease. The impregnating agent for electronic components of the present invention may contain various surfactants, such as polyoxyethylene glycol dimethyl siloxane, alkyl fluoride surfactants, etc., in order to obtain a film with a smooth surface, and may further contain colloidal surfactants. There is no problem in adding and blending silica or the like. The impregnating agent for electronic components of the present invention is cured after being impregnated into electronic components, and the curing conditions may be curing at 150 to 180° C. for 1 to 4 hours. Note that the impregnation method may be any known method, such as pressure impregnation method, vacuum impregnation method, normal pressure impregnation method, etc. In particular, the following vacuum impregnation method is more effective for improving the characteristics of electronic components. It is true. Vacuum impregnation method (1) Place the parts to be impregnated into a container, then add impregnating agent so that the parts are completely immersed, (2) Place the container in a device that can reduce pressure, and reduce the pressure of the entire system (in this case, the parts Bubbles are generated from the surface of the part. Bubbles initially appear from the entire surface, but after a while they begin to be generated only from the voids of the part. Note that it is preferable that the degree of vacuum is as high as possible;
(20 to 50mmHg is sufficient), (3) When the generation of bubbles has stopped or is almost gone, return the system to normal pressure. (4) After removing the parts from the impregnating liquid and cutting off any excess,
Immerse it in a solvent such as trichloroethylene, toluene, acetone, etc. to remove the impregnating agent attached to the surface. (5) Pull it out of the solvent, thoroughly evaporate the remaining solvent at room temperature, and then heat and dry as necessary. (6) Cure at a predetermined temperature. Effects of the Invention The impregnating water for electronic parts of the present invention effectively prevents impurities such as Cl ^- and Na ⁺ from entering electronic parts,
Moreover, even if a silicone film is formed on the surface of an electronic component, the adhesive adheres well due to the acrylic group contained in the composition. EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples and Comparative Examples, but the present invention is not limited to the Examples below. In addition, in the following examples, parts indicate parts by weight. Example 1 γ-methacryloxypropyltrimethoxysilane (viscosity 1.0 centistokes at 25°C)
150 parts, dimethyldimethoxysilane (viscosity 0.3 centistokes at 25°C) 50 parts, methanol
Pour 50 parts into a heatable flask and stir while stirring.
150 parts of a 0.2N-HCl aqueous solution was gradually added dropwise, and after the dropwise addition was completed, the mixture was stirred at room temperature for 3 hours, and then reacted with heating reflux for 8 hours to complete the reaction. After cooling the reaction solution to room temperature, 0.5 part of propylene oxide was added to neutralize it, and it was filtered through Millipore.
The solvent was removed at 80° C./10 mmHg to obtain a silicone composition for impregnating electronic components (yield: 85%). The viscosity of this composition at 25°C is 4.5 centistokes, the refractive index is 1.406, the extracted water conductivity is 5.8μ≠/cm,
Na and K ion contents are less than 1 ppm each, Cl
The ion concentration was 2 ppm. Further, a strong film was obtained by curing this silicone composition at 150° C. for 1 hour. Example 2 100 parts of γ-methacryloxypropyltrimethoxysilane, 50 parts of methacryloxypropyldimethoxymethylsilane (viscosity 1.0 centistokes at 25°C), 50 parts of dimethyldimethoxysilane
and 50 parts of methanol were placed in a heatable flask, and 15 parts of a 0.5N HCl aqueous solution was gradually added dropwise while stirring. After the dropwise addition was completed, the mixture was stirred at room temperature for 3 hours, and then heated and refluxed for 8 hours to stop the reaction. finished. Next, the reaction solution was cooled to room temperature, neutralized by adding 0.5 part of propylene oxide, filtered through Millipore, and the solvent was removed at 80° C./10 mmHg to obtain a silicone composition for impregnating electronic components. (yield 87
%). The viscosity of this composition at 25°C is 9.0 centistokes, the refractive index is 1.4406, the extracted water conductivity is 10μ≠/cm,
Na and K ion contents are less than 1 ppm each, Cl
The ion concentration was 4ppm. Further, a strong film was obtained by curing this silicone composition at 150° C. for 1 hour. Example 3 100 parts of γ-methacryloxypropyltrimethoxysilane, 15 parts of dimethoxymethylphenylsilane (viscosity 1.0 centistokes at 25°C),
Put 85 parts of dimethyldimethoxysilane and 50 parts of methanol into a heatable flask, and add while stirring.
15 parts of a 0.5N-HCl aqueous solution was gradually added dropwise, and after the dropwise addition was completed, the mixture was stirred at room temperature for 3 hours, and then reacted by heating reflux for 8 hours to complete the reaction. Next, the reaction solution was cooled to room temperature, neutralized by adding 0.5 part of propylene oxide, filtered through Millipore, and the solvent was removed at 80° C./10 mmHg to obtain a silicone composition for impregnating electronic components. (Yield 92
%). The viscosity of this composition at 25° C. was 23 centistokes, the conductivity of extracted water was 12 μ≠/cm, the contents of Na and K ions were each less than 1 ppm, and the content of Cl ions was 2 ppm. In addition, this silicone composition was heated at 150℃/
A strong film was obtained by curing for 1 hour. Examples 4 to 10, Comparative Examples 1 and 2 Silicone compositions for impregnating electronic components were obtained from the components shown in Table 1 in the same manner as in Examples 1 to 3 above.
For comparison, a silicone composition for impregnating electronic components consisting of dimethylsiloxane and methylhydropolysiloxane was also obtained. Next, the heat resistance and adhesive properties of these silicone compositions were measured using the measurement methods shown below. The results are also listed in Table 1. Measurement method Moisture resistance: Aluminum wiring (film thickness 1μ, line width 5μ)
After mounting the silicone chip on a 14-pin DIP frame, the compositions of Examples 4 to 10 were applied to electronic components sealed with thermosetting epoxy resin.
The compositions of Comparative Examples 1 and 2 were each subjected to vacuum impregnation treatment under reduced pressure, then cured at 180°C for 4 hours, and PC
T (121°C, 2 atm) and the open failure rate of the aluminum wiring was measured. Adhesion: 100 electronic components impregnated with the compositions of Examples 4 to 10 and Comparative Examples 1 and 2 and cured were temporarily fixed to an epoxy laminate using an acrylic adhesive. Dip the epoxy laminate facing upward into a solder bath at 260℃ for a specified number of times.
We measured the number of electronic components that came off the epoxy laminate and fell into the solder bath when we pulled it out of the solder bath.
I looked into that rate.

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[Claims]

1 A high-temperature method characterized by printing and firing a conductive paste containing crystallized glass and an insulating paste mainly composed of crystallized glass through an oxide film formed on a highly thermally conductive substrate. Conductive thick film multilayer wiring board. 2 High thermal conductivity substrate is AlN, SiC/BeO, SiC,
The highly thermally conductive thick film multilayer wiring board according to claim 1, which is made of Cu/W, ZrB ₂ or the like. 3 When the conductor paste is 100 parts by weight of Au, α=
2 to 5 parts by weight of crystallized glass having a thermal expansion coefficient of 2.5 to 4.5×10 ^-6 /°C, 0.1 to 0.1 parts by weight of copper oxide powder (CuO)
1 part by weight of Ag powder, and 3 parts by weight or less of Ag powder. 4. The highly thermally conductive thick film multilayer wiring board according to claim 1, wherein the insulating paste is mainly composed of crystallized glass having a coefficient of thermal expansion of α=2.5 to 4.5×10 ⁻⁶ /°C. 5. The highly thermally conductive thick film multilayer wiring board according to claim 1, wherein the oxide film is formed by surface treatment in a humidified reducing atmosphere with a dew point of -30 to +5°C at 1200 to 1450°C.

Claims (1)

Impregnating agent for electronic parts. 2. Claim 1 in which the contents of Na ⁺ and Cl ^- in component (A) and component (B) are each 10 ppm or less
Impregnating agent for electronic components as described in . 3. The impregnating agent for electronic components according to claim 1 or 2, wherein the components (A) and (B) each have a viscosity of 3 to 100 centistokes at 25°C.