JP3079396B2 - Hybrid IC - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hybrid IC in which an electronic component element on a substrate is sealed with a protective layer of an insulating resin and a shield layer is formed thereon.

[0002]

2. Description of the Related Art A hybrid IC is used by being mounted on a printed wiring board, and its electronic component elements are covered with a protective layer of an insulating resin to be protected from an external environment. A shield layer is formed so as to block the influence of the electromagnetic waves emitted from the hybrid IC on the outside and the influence on the hybrid IC from the outside.

[0003] The formation of the shield layer includes a means for providing an exterior of a metal case and a means for applying a conductive substance disclosed in Japanese Utility Model Application Laid-Open No. 75192/1986. The former has a large shape and is expensive. On the other hand, the latter has the advantage that the entire hybrid IC can be miniaturized and the manufacturing cost is low.

[0004] However, a conductive paint is usually used for the above-mentioned conductive material. However, conventionally, a conductive material having a viscosity suitable for coating and having a sufficient conductivity has been proposed. The fact is that it has not been done. There are no satisfactory dip coatings that can be used especially for workability.

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to make a shield layer dip-coatable and have sufficient conductivity.

[0006]

In order to solve the above-mentioned problems, according to the present invention, an electronic component element is mounted on a substrate, and the element is covered with a protective layer of an insulating resin. A number of lead terminals protruding from the protective layer, on the protective layer, comprising the following composition (A) to (D);
3 to 30 parts by weight of the resol-type phenol resin formed a shield layer of a conductive paint having a hydroxyl group or a methylol group as a butoxy group, and the shield layer was electrically connected only to the ground lead terminal among the lead terminals. It was a configuration.

(A) 100 parts by weight of metallic copper powder coated with 0.05 to 0.2 parts by weight of titanate, zirconate or a mixture thereof (B) 5 to 33 parts by weight of resole type phenol resin (C) 0.5 to 3.5 parts by weight of amino compound (D) 3.0 to 10 parts by weight of chelating layer forming agent.

The above-mentioned resole type phenol resin is preferably as follows. The infrared transmittances of the 2-substituted product, 2,4-2-substituted product, 2,4,6-3-substituted product, methylol group, dimethylene ether, and phenyl group are represented by 1, m, n, a, b, c
Between each transmittance, (a) l / n = 0.8-1.2 (b) m / n = 0.8-1.2 (c) b / a = 0.8-1.2 ( D) A resol-type phenol resin that satisfies the relationship of c / a = 1.2 to 1.5.

The protective layer and the shield layer are preferably formed by dip coating in which a substrate on which electronic component elements are mounted is sequentially immersed in an insulating resin bath and a conductive paint bath.

[0010] The substrate material is an insulating material such as an epoxy resin, a phenol resin, a glass fiber, and a ceramic.

The metallic copper powder may have any shape such as a flake, a dendrite, a sphere, and an irregular shape. Particle size is 10
It is preferably 0 μm or less, particularly preferably 1 to 30 μm.
Particles having a particle size of less than 1 μm are not preferred because they are easily oxidized and the conductivity of the obtained coating film (coating film) is reduced.

The metallic copper powder may be titanate, zirconate, or a mixture thereof (hereinafter, referred to as a dispersibility-imparting agent).
By coating the surface, the fine dispersion in the resin mixture is promoted, thereby stabilizing the quality of the conductive paint and improving the conductivity. The amount of the dispersibility-imparting agent added is 0.05 to 0.2 with respect to 100 parts by weight of metallic copper powder.
Parts by weight. When the amount of the dispersibility-imparting agent is less than 0.05 parts by weight, the conductivity of the coating film is reduced. When the amount exceeds 0.2 parts by weight, the adhesion to the copper foil (copper alloy foil) and the soldering are reduced. Heat resistance is not preferred. The dispersibility-imparting agent itself may be added alone, or the solvent may be removed after being added as a solution. Incidentally, this surface treatment makes it unnecessary to add a dispersant.

If the content of the resol-type phenolic resin is less than 5 parts by weight, the metallic copper powder is not sufficiently bound, and the resulting coating film becomes brittle. If the amount exceeds 33 parts by weight, the conductivity will decrease. Preferably, it is 9 to 20 parts by weight. Of this resole type phenol resin, 3 to 30
The parts by weight are obtained by converting a hydroxyl group or a methylol group into a butoxy group by etherification as shown in Chemical Formulas 1 and 2 below. As a result, bleeding during printing can be eliminated, and the effect cannot be expected with less than 3 parts by weight, and when it exceeds 30 parts by weight, a problem occurs in conductivity.

[0014]

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[0015]

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Further, the stoichiometry and the amount of the 2-substituted product are λ,
The amount of 2,4-2 substituted product is μ, the amount of 2,4,6-3 substituted product is ν, the amount of methylol group is α, the amount of dimethylene ether is β,
Assuming that the amount of phenyl groups is γ, l / n and m / n
Means that λ / ν and μ / ν are small. That is, the 2-1 substitution amount λ, 2,4-2
This means that the 2,4,6-3 substituted amount ν is larger than the substituted amount μ. Further, b / a, c /
When a is large, β / α and λ / α are small. That is, it means that the amount α of methylol groups is larger than the amount β of dimethylene ether and the amount λ of phenyl groups.

In general, as the amount of the 2,4,6-3 substituted product ν increases, the crosslink density of the resol-type phenol resin increases, so that the smaller λ / ν and μ / ν are, that is, 1 / n , M / n is higher, the conductivity of the coating film is better. However, on the contrary, the coating film tends to be hard and brittle, and the physical properties deteriorate. On the other hand, if β / α is small, the solderability of the coating film deteriorates, and if γ / α is large, the conductivity of the coating film deteriorates.

Therefore, in the obtained conductive paint, the resol-type phenolic resin having an appropriate hardness of the coating film and having both good conductivity and good solderability is the l / n, m / n , B / a are respectively 0.8 to 1.2, c
It is suitable that / a is 1.2 to 1.5.

The chelating layer forming agent is at least one selected from aliphatic amines such as monoethanolamine, diethanolamine, triethanolamine, ethylenediamine, triethylenediamine and triethylenetetramine.
Is a seed. The chelate layer forming agent prevents oxidation of the metallic copper powder and contributes to maintaining conductivity. The compounding amount is 3.0 to 10 parts by weight based on 100 parts by weight of the metal copper powder. When the amount is less than 3.0 parts by weight, the conductivity of the coating film decreases, and when the amount exceeds 10 parts by weight, the conductivity of the coating film also decreases.

The amino compound acts as a reducing agent in addition to the conductivity improver, prevents oxidation of the metallic copper powder, and contributes to maintaining conductivity. The compounding amount is 0.5 to 3.5 parts by weight based on 100 parts by weight of the metal copper powder. When the amount is less than 0.5 part by weight, the conductivity of the coating film is remarkably reduced, and conversely, 3.5.
If the amount exceeds the weight part, the conductivity is saturated and no further improvement is observed.

Specific examples of the amino compound include one or more of aniline, diphenylamine, phenylenediamine, diaminonaphthalene, anisidine, aminophenol, diaminophenol, acetylaminophenol, aminobenzoic acid, N, N-diphenylbenzidine and the like. Some examples include, but are not limited to:

Incidentally, a common organic solvent can be appropriately used for the conductive paint in order to adjust the viscosity. For example, known solvents such as cellosolve acetate, carbitol, butyl carbitol, and butyl cellosolve acetate.

[0023]

As can be understood from the above description, the conductive paint according to the present invention having such a structure has excellent conductivity and adhesion of the coating film, and has high conductivity even if the viscosity is low. is there. For this reason, like the protective layer, the shield layer can be easily formed by dip coating on the conductive paint bath.

[0024]

First, 100 parts by weight of dendritic metal copper powder having a specific surface area of 0.4 m ² / g or less and a hydrogen reduction weight of 0.25% or less having a particle size of 5 to 10 μm was placed in a stirrer. Was added little by little and the mixture was stirred to coat the titanate on the surface of the metallic copper powder. Thereafter, the metal copper powder was added with aminophenol as a reducing agent, triethanolamine as a chelating layer-forming agent, and an infrared transmittance ratio (l / n: 1.
03, m / n: 1.02, b / a: 0.96, c / a:
Table 1 shows each of the resol type phenol resins of 1.31).
And a mixed solvent of ethyl carbitol and butyl cellosolve was added as a solvent, and the mixture was kneaded in a fixed position with a triaxial roll for 20 minutes.
04 so as to obtain 20 to 40P to obtain a conductive paint bath.

In place of ethyl carbitol and butyl cellosolve, known compounds such as butyl carbitol, butyl carbitol acetate, butyl cellosolve acetate, methyl isobutyl ketone, toluene and xylene can be used.

[0026]

[Table 1]

On the other hand, as shown in FIG. 1, electronic components such as various chip components 2 and resistors 3 are mounted or printed on an epoxy resin substrate 1 and a required number of lead terminals 4. ..., 4a is projected.

The substrate 1 is immersed in an epoxy resin bath by masking the base 4a 'of the ground lead terminal 4a to form a protective layer 5 having a required thickness. During the immersion, the immersion is performed up to the exposed portion (connection portion) of the ground lead terminal 4a, that is, while leaving the connection portion, so that the other lead terminals 4 are surely filled and covered with the resin. This is to prevent a short-circuit between a later-described shield layer 6 and the lead terminal 4.

Subsequently, the substrate 1 is immersed in the conductive paint bath with the masking removed, to form a shield layer 6 having a required thickness. The immersion depth does not reach the edge of the protective layer 5 on the lead terminals 4 and 4a side. By this immersion, the conductive paint enters the masking portion 4a ', and the ground lead terminal 4a and the shield layer 6 are electrically connected.

The superiority of the conductive paint b of this example can be understood by the following test.

That is, as shown in FIG. 2, each of the conductive paints b in Table 1 was applied to a through-hole 33 (having a hole diameter of 0.8 mm) of a paper phenol substrate 32 having a thickness of 1.6 mm using an 80-mesh tetron screen. Embedded by screen printing. Then, after drying at 25 ° C. ± 5 ° C. for 24 hours, the coating was cured by heating at 160 ° C. for 30 minutes using an air oven.

As shown in FIG. 3, the through-holes 33 have a horizontal line of 20 holes, and a large number of such rows A to K are provided. On the front side of the substrate 32, two adjacent through-holes 33, 33,... Are connected by a copper foil 34 (see FIG. 2A), and two through-holes not connected by the copper foil 34 on the front side. 33, 33... Are copper foils 34 ', 3
4 '(see FIG. 4B).

Ends 41-42, 42-43, 43-44
The series resistance value of 20 holes between them was measured and divided by 20 to obtain the resistance value per through hole. The results of evaluating the conductivity of the coating film b based on this resistance value are shown in the lower column of Table 1.

The presence or absence of bleeding was evaluated as follows. That is, those which were printed out by 100 shots and oozed out of the copper foil land portion were evaluated as "bleeding", and those which did not ooze out of the copper foil land portion were evaluated as "no bleeding".

As apparent from the results, Examples 1 to
In No. 3, the conductive paint b according to the present invention is appropriately combined with a specific composition, and high conductivity is obtained. The high conductivity indicates that the paint b has flowed smoothly into the through-hole 33 in addition to the high conductivity of the coating film b (conductive paint) itself. (Coating) The effect can be obtained.

On the other hand, Comparative Examples 1 and 2 have too much resol type phenolic resin, and all have poor conductivity. In Comparative Example 3, the amount of the resole phenol resin having a butoxy group (XPL4289C) was small, and bleeding occurred.

[0037]

The present invention is configured as described above.
By the dip coating, a hybrid IC having a shield layer having excellent conductivity can be obtained. In addition, workability is good, and manufacturing cost can be reduced.

[Brief description of the drawings]

1A is a front view of one embodiment, and FIG. 1B is a cross-sectional view taken along line XX of FIG.

FIG. 2 is a cross-sectional view of a resistance test piece.

3A is a plan view of the test piece, and FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Chip component 3 Resistance 4 Lead terminal 4a Ground lead terminal 5 Protective layer 6 Shield layer b Conductive paint (coating) 33 Through hole 35, 34 'Copper foil

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI H05K 3/28 (56) References JP-A-3-190195 (JP, A) JP-A-4-11675 (JP, A) JP-A-2-18463 (JP, A) JP-A-5-29736 (JP, A) JP-A-4-93368 (JP, A) Japanese Utility Model Publication No. 58-103196 (JP, U) (58) Int.Cl. ⁷ , DB name) H05K 9/00

Claims (2)

(57) [Claims] An electronic component element is mounted on a substrate, and the electronic component element is covered with a protective layer of an insulating resin, and a required number of lead terminals are protruded from the protective layer.
3 to 30 parts by weight of the resol-type phenol resin forms a shield layer of a conductive paint having a hydroxyl group or a methylol group as a butoxy group, and the shield layer is formed of the lead terminal. A hybrid IC electrically connected only to the ground lead terminal. (A) 100 to 100 parts by weight of metallic copper powder coated with 0.05 to 0.2 parts by weight of titanate, zirconate or a mixture thereof (B) 5 to 33 parts by weight of resole type phenol resin (C) amino compound 0 0.5 to 3.5 parts by weight (D) 3.0 to 10 parts by weight of a chelate layer forming agent 2. The hybrid IC according to claim 1, wherein the resol type phenol resin is as follows. The infrared transmittances of the 2-substituted product, 2,4-2-substituted product, 2,4,6-3-substituted product, methylol group, dimethylene ether, and phenyl group are represented by 1, m, n, a, b, c
Between each transmittance, (a) l / n = 0.8-1.2 (b) m / n = 0.8-1.2 (c) b / a = 0.8-1.2 ( D) A resol-type phenol resin that satisfies the relationship of c / a = 1.2 to 1.5.