JPH073195U - Exterior structure of hybrid integrated circuit parts - Google Patents

Abstract

(57) [Summary] [Purpose] To disperse magnetic material particles in resin coating at a density that does not interfere with coating, and to increase the coating resin film thickness on the exterior, which leads to enlargement of circuit components. In addition, the external structure of the hybrid integrated circuit component is provided, which can protect the internal circuit and can achieve a satisfactory shield effect against the external magnetic field and electric field. An exterior structure of a hybrid integrated circuit component in which at least a part of the circuit substrate 1 is covered with a material that attenuates electromagnetic waves, and the circuit component 3 on the circuit substrate having a lead 2 is thermally and mechanically A first layer 5 made of a resin in which magnetic material particles are dispersed, and a magnetic material fixed on the surface of the first layer through an undercoat layer 4 which is usually provided to fulfill the role of buffering. The second layer 7 and the third layer 8 made of a resin for sealing the magnetic material particles of the second layer are formed in this order.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an exterior structure for a hybrid integrated circuit component.

[0002]

[Prior art]

 In recent years, many circuit devices that can prevent the influence of electromagnetic noise have been proposed. However, even in a hybrid integrated circuit, one in which a shielding effect is applied to a resin exterior is proposed.

A typical example thereof is a resin coating in which ferrite powder is dispersed, which is applied around a circuit board of a hybrid integrated circuit component and then cured, and mainly shields against a magnetic field. Is to do.

That is, as shown in the schematic cross-sectional view of FIG. 3, in a hybrid integrated circuit component configured by mounting various circuit components 3 on a circuit board 1 having leads 2, usually, thermal and mechanical A layer 5 made of a resin in which a magnetic material powder having magnetic permeability is dispersed in a base paint is formed through an undercoat layer 4 provided for the purpose of buffering, and the circuit is electrically and physically In general, a sealing layer 6 made of a resin coating is formed for the purpose of protecting the internal circuit against magnetic disturbance and further sealing the internal circuit.

Further, it is also known that a resin coating in which a ferrite powder having magnetic permeability and a conductive metal powder are dispersed is alternately applied and cured to shield both a magnetic field and an electric field.

[0006]

[Problems to be solved by the device]

 However, in the above structure, (1) in order to obtain a satisfactory shielding effect, it may be necessary to disperse the ferrite powder in the resin coating material at such a density that the coating is hindered. Even if coating can be performed, cracks may occur on the surface of the exterior during the curing process. (2) If a resin paint in which ferrite powder is dispersed at a normal density is used to solve the above-mentioned problem (1), a large amount of resin paint must be applied, and the film thickness of the exterior is inevitably increased. However, there was a problem that the number of hybrid integrated circuit components increased and the size of hybrid integrated circuit components was increased.

Therefore, the object of the present invention is to disperse the particles of the magnetic material in the resin at a density that does not interfere with the coating, and yet to increase the electrical and physical properties of the internal circuit without increasing the resin film thickness of the exterior. (EN) Provided is an exterior structure of a hybrid integrated circuit component, which can obtain a satisfactory shield effect against an external magnetic field and an electric field as well as a mechanical protection.

[0008]

[Means for Solving the Problems]

 The present inventor has conducted research to achieve the above-mentioned object, and in the conventional exterior structure, as shown in the graph of FIG. 5, magnetic material particles such as ferrite particles coated on the undercoat layer 4 are used. The ferrite content C in the dispersed resin layer (first layer) 5 depends on the resin coating material to be applied, but it is constant in the thickness direction of the coating film, and it depends on the viscosity and the necessity of coating work. Since there is a limit, it was found that the above-mentioned problems had occurred, and as a result of further study, as shown in the graph of Fig. 4, the ferrite-dispersed resin on the undercoat layer 4 is often applied in general. After coating and forming the layer (first layer) 5, the ferrite powder is adhered to the resin surface in a semi-dried state, and is fixed as the resin hardens to form the second layer 7, and the ferrite powder is further sealed on it. A resin, preferably the first layer In this way, if the ferrite-dispersed resin is applied and cured as the third layer 8, the second layer 7 has a high density of ferrite powder even if the film thickness of the coating film is the same as that of the conventional case. It is possible to dramatically increase the maximum value of the ferrite content in the coating film to be coated, and thus to obtain a remarkable shielding effect, so that it is possible to solve the problems in the conventional coating structure. Found and reached the present invention.

That is, the present invention is, firstly, an exterior structure of a hybrid integrated circuit component in which at least a part of a circuit board is covered with a material that attenuates electromagnetic waves, and a resin in which magnetic material particles are dispersed. A circuit board in the order of a first layer composed of, a second layer composed of a magnetic material fixed on the surface of the first layer, and a third layer composed of a resin covering the magnetic material particles of the second layer in this order. The exterior structure of the hybrid integrated circuit component is characterized by being formed as follows: Second, the exterior structure in which the magnetic material particles are mainly composed of a ferrite material having an insulating surface: the third The magnetic material particles are mainly composed of a manganese-zinc-based ferrite material. The second exterior structure is as follows: Fourth, the third layer is a resin in which the magnetic material particles are dispersed. Any of the above exterior structures consisting of: 5, the exterior structure is a structure in which only predetermined circuit elements on a circuit board are covered, and the fourth exterior structure is: sixth, the third layer is made of a resin in which a conductive filler is dispersed. The exterior structure according to any one of 1 to 3 is provided.

[0010]

[Action]

 In the exterior structure of the hybrid integrated circuit component of the present invention, the first layer made of resin in which the particles of the magnetic material are dispersed is formed, and the magnetic material is fixed as the second layer on the surface thereof.

Even if the magnetic material material (second layer) fixed on the surface of the first layer disperses the magnetic material particles in the resin of the first layer at a density that does not interfere with the coating, the external magnetic field It is possible to obtain a sufficient shield effect against.

By using a ferrite material having an insulating surface as the magnetic material particles, it is possible to secure sufficient insulating properties with respect to the conductor pattern on the substrate.

By using a manganese-zinc (Mn-Zn) -based ferrite material whose conductivity is close to that of an insulator as the magnetic material particles, the magnetic material particles can be used as they are in resin without any special insulation treatment. Can be dispersed.

The magnetic material is retained by forming a third layer of a resin in which particles of the magnetic material are dispersed on the second layer of the magnetic material fixed on the surface of the first layer. In addition, the shield effect can be strengthened.

By covering only predetermined circuit elements on the circuit board, it is not necessary to form an outer cover on a portion that does not require a shield, which leads to downsizing of the hybrid integrated circuit component, and further, the same circuit board The predetermined circuit element can be shielded from a portion that emits electromagnetic noise.

The magnetic material is retained by forming a third layer of resin in which a conductive filler is dispersed on the second layer of magnetic material fixed on the surface of the first layer. In addition, the effect of shielding the electric field is obtained.

[0017]

Embodiment 1 FIG. 1 is a schematic cross-sectional view showing the exterior structure of a hybrid integrated circuit component produced in this embodiment, and FIG. 6 is a graph showing the shielding effect in the exterior structure obtained by the present invention. A description will be given below with reference to these drawings. (1) 96% alumina ceramic circuit with external dimensions of 7.0 x 25.0 x 1.2 mm After forming the predetermined electrodes on the substrate 1, mount various parts 3 and install them on the edge of the substrate. A series of leads 2 were connected to form a serial inline (SIL) type hybrid integrated circuit component. (2) Next, an insulating resin was applied around the substrate by a dipping method and cured to form an undercoat layer 4. (3) Subsequently, an epoxy resin (hereinafter referred to as a ferrite dispersion resin) in which 50, 65, 70 and 75 wt% of Mn-Zn based ferrite material powder (hereinafter referred to as "ferrite powder") is dispersed respectively. Of the ferrite dispersion resin is applied to the undercoat layer 4 by the dip method to form the first layer 5, and then in a semi-dried state, the ferrite powder is densely adhered to the resin surface to A second layer 7 was formed by being fixed together with curing.

Here, as the ferrite powder, a powder of Mn—Zn based ferrite was used. This is because the Mn—Zn based ferrite is close to an insulator from the viewpoint of conductivity, and has an insulating property between circuit components. This is because there is no possibility of damaging the powder, and other materials such as Ni—Zn ferrite, strontium ferrite, and γ-Fe ₂ O ₃ may have their surface treated with an insulation treatment.

Further, the same Mn—Zn-based ferrite powder was used as the ferrite powder used for forming the first layer 5 and the second layer 7, but this was due to the difference in thermal expansion coefficient between the first layer and the second layer. And the effect of preventing peeling between the first layer and the second layer. Of course, another type of magnetic material may be used, but it is desirable to use a material that has a small difference in thermal expansion coefficient between the two as described above. (4) Further, the same ferrite-dispersed resin as the above was applied as the third layer 8 thereon by the dip method and cured to complete the exterior structure of the hybrid integrated circuit component.

The ferrite-dispersed resin used in the third layer 8 may be made of a ferrite powder or resin different from the one used in (3) above.

It should be noted that no crack was observed during curing in any of the above-mentioned outer casings having a ferrite powder content. FIG. 7 is a graph showing the shielding effect of a hybrid integrated circuit component which is obtained by coating and curing a resin paint in which ferrite powders are dispersed in 50, 65, 70 and 75% by weight, respectively, and FIG. 8 is a ferrite dispersion resin shown in FIG. FIG. 9 is a graph showing the shielding effect of a hybrid integrated circuit component which is obtained by coating the coating material twice and then curing it. As can be seen from FIGS. 6 and 8, the exterior of the present invention has approximately twice the shielding characteristics (shield Effect), it is possible to obtain sufficient shielding characteristics without increasing the thickness of the exterior.

It should be noted that the above-mentioned shielding effect is a hybrid effect produced by mounting the Hall element to which the measuring equipment is connected on the circuit board and then forming the exterior of the present embodiment or the comparative example on the circuit board in the previous period. It is obtained by preparing an integrated circuit component and measuring how much the electromagnetic wave emitted from the electromagnetic wave source toward the circuit component and reaching the Hall element is attenuated.

In addition, the shielding effect of the exterior according to the present invention is slower than the conventional one even if the content of the ferrite powder is low. Therefore, it is necessary to add another filler to the exterior resin. Also, it is possible to suppress the deterioration of the shield characteristics to a low level.

Since the undercoat layer 4 is formed as the lower layer of the first layer 5 in the exterior structure of the present embodiment, depending on the thickness of the undercoat layer 4, the inclusion of the ferrite powder having an insulating surface may be included. Even if the ferrite-dispersed resin is not used, there may be no problem with the insulating property to the conductor pattern on the substrate, but the undercoat layer 4 is not formed or the undercoat layer is not formed in order to prevent the resin film thickness from increasing. When the thickness of the layer 4 is reduced, it is desirable to use the ferrite dispersion resin in which the ferrite powder having the insulating surface as described above is dispersed.

[0025]

Second Embodiment FIG. 2 is a schematic cross-sectional view showing an exterior structure in this embodiment. In the first embodiment, the outer package is formed around the substrate of the hybrid integrated circuit component, but the outer package may be formed only on a part of the substrate as shown in FIG. 2, in which case electromagnetic noise of the same substrate is generated. It is possible to shield the part where the exterior is formed from the part.

[0026]

Example 3 After the ferrite powder was fixed on the surface of the ferrite-dispersed resin on the undercoat layer according to the procedure of Example 1, an epoxy resin in which powdery copper was dispersed was applied and cured on the ferrite powder. The exterior structure of the hybrid integrated circuit component was completed.

As a result, in addition to the magnetic field, the shield effect against the electric field can be obtained.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes and modifications can be made without departing from the scope of the claims of the present invention. It is possible to carry out a replacement or formation process.

For example, a second layer made of a magnetic material may be formed by fixing ferrite powder on the first layer by powder coating by electrostatic spraying after the first layer is completely cured. It is also possible to form the second layer by a sputtering method using a target made of a ferrite material.

[0030]

[Effect of device]

 As described above, in the exterior structure according to the present invention, the first layer made of the resin in which the magnetic material particles are dispersed is formed through the undercoat layer, and the magnetic material is fixed on the surface of the first layer. Therefore, even if the magnetic material is dispersed in the resin of the first layer at a density that does not interfere with the coating, a sufficient shielding effect can be obtained.

Furthermore, by holding a third layer made of a resin in which magnetic material particles are dispersed on the magnetic material (second layer) fixed on the surface of the first layer, the magnetic material is retained. In both cases, the shield effect can be enhanced, and by forming the third layer made of the resin in which the conductive filler is dispersed, the magnetic material can be retained and the shield effect against the electric field can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an exterior structure of a hybrid integrated circuit component created in one embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing an exterior structure according to another embodiment of the present invention.

FIG. 3 is a schematic sectional view showing an exterior structure of a conventional hybrid integrated circuit component.

FIG. 4 is a graph showing the characteristics of the exterior structure based on the present invention by the ferrite content in the thickness direction of the coating film.

FIG. 5 is a graph showing a ferrite content in a coating film thickness direction in a conventional exterior structure.

FIG. 6 is a graph showing the shielding effect of the exterior structure obtained according to the present invention.

FIG. 7 is a graph showing the shielding effect of a hybrid integrated circuit component which is obtained by coating and curing a resin coating material in which ferrite powders are dispersed in 50, 65, 70 and 75% by weight, respectively.

FIG. 8 is a graph showing the shielding effect of a hybrid integrated circuit component which is obtained by coating the ferrite-dispersed resin coating material shown in FIG. 7 twice and curing it.

[Explanation of symbols]

 1 circuit board 2 lead 3 circuit component 4 undercoat layer 5 first layer 6 encapsulating layer 7 second layer 8 third layer C ferrite content in ferrite dispersion resin Cm maximum ferrite content

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H05K 9/00 H

Claims (6)

[Scope of utility model registration request] 1. An exterior structure of a hybrid integrated circuit component in which at least a part of a circuit board is covered with a material for attenuating electromagnetic waves, the first layer comprising a resin in which magnetic material particles are dispersed, A second layer made of a magnetic material fixed on the surface of the first layer, and a third layer made of a resin covering the magnetic material particles of the second layer are formed in this order on the circuit board. Exterior structure for hybrid integrated circuit parts. 2. The exterior structure according to claim 1, wherein the magnetic material particles are mainly composed of a ferrite material having an insulating surface. 3. The exterior structure according to claim 2, wherein the magnetic material particles have a manganese-zinc based ferrite material as a main component. 4. The exterior structure according to claim 1, wherein the third layer is made of a resin in which the magnetic material particles are dispersed. 5. The exterior structure according to claim 1, wherein the exterior structure is a structure in which only predetermined circuit elements on a circuit board are covered. 6. The exterior structure according to claim 1, wherein the third layer is made of a resin in which a conductive filler is dispersed.