JPH01207993A - Electronic component - Google Patents

Abstract

PURPOSE:To ensure a sealing, and to prevent the influence of a mechanical shock or the like from the outside, by a structure wherein an opaque resin layer with a high hardness to which a silicate filler is added is formed on a high insulating first layer with a flexibility. CONSTITUTION:In an electronic component of a hybrid IC in which a resin coating is performed by means of a case potting method, a potting resin layer consists of a first layer 35 with which a circuit component received in a case 31 is covered, and a second layer 36 which is formed on the first layer 35 and closes the opening of the case 31. In this connection, the first layer 35 is made of a high insulating resin which does not contain substantially an additive of a colorant or the like, while the second layer 36 is made of a resin to which a silicate filler is added by the ratio of 10-100% with respect to the weight of the resin and which has a low transparency and a higher hardness than that of the first layer 35. As a result, these is no possibility that after potting, a cap is putted on the case to close the opening, and therefore a space is formed between the cap and a potting resin and gas, water and the like enter the space from the outside to fill it. Moreover, since there is not a cap covering process, the manufacturing cost can be lowered.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to electronic components such as hybrid ICs and various other functional devices coated with a resin by the case potting method.

Conventional technology Electronic components such as the hybrid 1c that have been resin-coated using the case potting method are not only surrounded by a resin layer, but also have a hard case covering the outside of the resin layer, so they cannot be coated using a dipping method. Compared to electronic components coated with resin using other methods, they have particularly good impact resistance, moisture resistance, and water resistance, but because the outside is covered with a hard case, Due to the thermal stress of
In order to prevent circuit boards and the like sealed with resin inside the case from being compressed, a resin that remains relatively flexible even after hardening is usually used as a potting resin that forms the resin layer inside the case.

For example, Figures 5 and 6 show a conventional hybrid I coated with a resin coating by the case potting method.
Hybrid I shown in FIG.
C10 accommodates the board 12 horizontally in a hard resin case 11 with an opening 11a at the top so that the surface of the board 12 on which the electronic circuit components 13 are mounted is on the opening 11a side. After the potting resin is placed in the case 11, a potting resin made of a resin material that remains relatively flexible even after hardening is injected into the opening 11a, and heated and hardened to form the substrate 12 and the electronic circuit component 13. A resin layer 14 is formed to cover the entire periphery, and the case 1
The opening 11a is closed by a lid 15 made of the same hard resin as 1.
is blocked.

Further, the hybrid IC 20 shown in FIG.
2 is inserted vertically, and this board 22 on which the electronic circuit component 23 is mounted is arranged parallel to the side wall of the case 21. After that, a botting resin is injected into the case 21 from the opening 21a. A resin layer 24 that remains flexible even after curing is formed by heating and curing the entire periphery of the board 22 and the electronic circuit component 23, and the opening 21a is formed by M25 made of the same hard resin as the case 21. is blocked.

Problems that Komei is trying to solve In this way, the conventional hybrids 1 (, 10, 2) coated with resin by the case-botting method
0, a resin material that remains relatively flexible even after curing is used as the potting resin to protect electronic circuit components from thermal stress, but the resin layer formed inside the case 11.21 14. If the 24 is soft, it will not provide sufficient protection against external pressure and impact, so case 1
In order to close the openings 1ja and 21a of 1°21 and protect them from external pressure etc., the hard resin M2S and 25
was essential. Therefore, after the potting resin is injected into the cases 11 and 21, the M2S is formed of the same material as the hard case before or after heat curing.
, 25 and the opening 11a.

21a had to be occluded. In particular, in the case of the hybrid ICl0 shown in Fig. 1, as the potting resin,
If a transparent resin containing no coloring agent or filler is used to achieve high insulation, the opening 11 should be
It was necessary to cover the inside of a with a lid. In this way, hybrid-IC using the conventional case-botting method
In the case of 10°20, 115.25 was applied to the openings 11a and 21a of the case 11°21 in the manufacturing process, which resulted in an increase in cost due to the increased number of cold steps.

Hybrid I with two resin coating layers
Examples of C include Japanese Patent Application Laid-Open No. 60-245293, Japanese Patent Application No. 194013-1983, and Japanese Patent Application No. 1987-277586.
As shown in the above publications, all of these are two-layer coating resin layers formed by the dipping method, so there is little risk of reliability deterioration due to thermal stress, and hybrid coatings are formed by the case-botting method. Since there is no component equivalent to the IC case lid, and the resin layer is formed by immersing the substrate in a resin liquid, it cannot be applied to the case botting method.

Also, in the past, there are some electronic components such as hybrid ICs made using the case-botting method that do not have lids.
For example, in the case of a hybrid IC that uses potting resin with carbon powder added to hide the inside of the case, the insulation properties may be reduced, leading to circuit damage, leaks, malfunctions, etc. Hybrid I with a thick layer of botting resin to protect against impact
In the case of C, the case becomes larger and the cost increases, and if a hard botting resin is used to protect against impact with a small amount of resin, thermal stress increases and reliability decreases. There are problems, and the challenge is to solve these problems.

This invention was made in view of the above-mentioned problems, and it effectively protects the electronic components inside the case with a small amount of botting resin. The aim is to provide electronic components through the case botting method, which eliminates the need for case profits.

Means for Solving the Problems As a means for solving the above problems, the present invention provides an electronic component such as a hybrid IC coated with a resin by a case botting method, in which a potting resin layer is applied to a circuit component housed in a case. and a second layer formed on the first layer to close the opening side of the case, and the first layer does not substantially contain additives such as colorants. The second layer is made of a highly insulating resin, and the second layer is made of a finely powdered silica-based filler that accounts for 10% of the weight of the resin.
It is characterized in that it is formed of a resin with low transparency and higher hardness than the first layer, which is added in an amount of 0 to 100%.

Function: By configuring as described above, by covering the circuit component with the first layer having high insulation and flexibility, the circuit component is insulated and protected against thermal stress. Furthermore, since a silica-based filler is added to form an opaque and highly hard resin layer on the first layer, the circuit components inside the case are reliably hidden, and the circuit components are not accessible from the outside. The effects of impact, etc. are effectively prevented.

EXAMPLE Hereinafter, an example of this light beam will be explained with reference to FIGS. 1 to 4.

The botting resin used when resin-coating electronic components such as hybrid ICs by the woosbotting method is a highly insulating first resin layer that covers the circuit board and electronic circuit components housed in the case. The botting resin is formed on the first resin layer to hide the inside so that it cannot be seen, and external pressure, impact, etc. can be applied to the circuit board and electronic circuits through the first resin layer. Botting resin is used to form a high-hardness second resin layer that closes the opening side of the case so as not to reach parts, etc., but in each embodiment, botting resin to form the first resin layer is used. As the resin, a two-component thermosetting silicone resin containing no colorant or filler is used, and as a potting resin for forming and covering the second resin layer, a coloring agent is added to the two-component thermosetting silicone resin. A finely powdered silica-based filler was added as a filler.

In addition, the amount of the fine powder silica filler added to the botting resin forming the second resin layer, the viscosity of the botting resin liquid, the defoaming property after injection of the botting resin liquid, and the amount of the botting resin liquid after heating and curing are also included. The relationship between hardness, hiding property after heat curing, and volume resistivity after heat curing was measured when the above-mentioned addition amount was 2 to 100%, and as a comparative example, filler Similar measurements were performed on the botting resin forming the first resin layer to which no additives were added, and the measurement results are shown in Table 1.

Note that the amount of the fine powder silica filler added is expressed as a weight ratio with respect to the case where the two-component thermosetting silicone resin is taken as 100. The curing conditions were as follows: heating at 70° C. for 30 minutes to dry to the touch, and then heating at 150° C. for 1 hour for curing.

In addition, the viscosity of the botting resin liquid was measured using a BM type viscometer (3
10 to 100 poise.
e) was measured at 12 rpm, and 100 poise or more was measured at 5 rpm. However, the rotor was set in the botting resin liquid, and the value was measured one minute after the rotor started rotating.

On the other hand, the hardness after curing is measured using a spring type hardness tester (JISA
(type).

Furthermore, regarding the hiding property after curing, 0.3 seconds on the blank surface
Create a test paper by drawing a 5myn grid with black lines of width, place a piece of resin with a thickness of 1 rtrm to 5rRm on the test paper, and pass through the resin piece from above and if the grid below is not visible. ○, if the grid was visible, it was marked as ×.

In addition, regarding the defoaming property of the bodding resin liquid, after stirring the potting resin liquid and mixing air, 1011
Defoaming was performed for 10 minutes with 1#IH (I), and if it was completely defoamed, it was 01. If it was not completely defoamed, it was marked as ×.

The volume resistivity after curing was determined by measuring the electrical resistance of a cured test piece, and calculating the volume resistivity from the thickness and cross-sectional area of the test piece.

To summarize the results for 1 ml from Table 1, first of all, regarding the hiding property, in order to hide the electronic circuit components at the bottom with a coating with a thickness of 5 mm JJ, the amount of fine powdered silica filler added must be 10 For example, if the amount added is 10%, the thickness is 4 mm, and the amount added is 20 to 30 mm.
%, the thickness is 2 mm when the addition amount is 50%, the desired hiding property is obtained at 1.5 mm when the addition amount is 100%, and when the addition amount is less than 10%, the thickness is 5 mm.
Even mm was insufficient. In addition, in the case of the resin material forming the 111th fat layer to which no filler was added, the hiding performance was evaluated as poor even at a thickness of 50 mm.

Regarding hardness, if there is a large difference in hardness between the resin material of the first resin layer and the resin material of the second resin layer, there will be a difference in the elastic modulus of the two, and when an external impact is applied, the interface between the two layers Since there is a risk of cracking and peeling, it is desirable that the hardness of the resin material of the second resin layer is within twice that of the resin material of the first resin layer.

Therefore, the hardness of the additive-free resin material of the first resin layer is 26H.
6, whereas the hardness of 100% added resin material is 49.
Since it is about twice as large as H6, the amount of filler added is 100
% or less is appropriate.

Next, properties other than hiding property and hardness are examined for each case where the amount of filler added is 10% to 100%.
The viscosity was about 10 times the initial viscosity even when the amount added was 100%, so there was no problem with workability. In addition, the defoaming property was completely defoamed within 10 minutes at 10 sH (I) in all cases, and there was no problem.
In either case, there was no problem when the distance was 100 cm or more.

From these results, it was found that the appropriate amount of the fine powder silica filler added is 10% or more and 100% or less by weight.

Next, based on the above study results, the case where the present invention is applied to various electronic components will be explained.

FIGS. 1(a), (b), and (c) sequentially show the manufacturing process of the hybrid IC of the first embodiment. The completed hybrid IC 30 (see FIG. 1(C)) has an opening at the top. A section 31a is provided (butapolybutylene lenticule 1-(
A case 31 made of hard resin such as PBT) and this case 3
1, an electronic circuit component 33 mounted on the circuit board 32, and a lead wire 34 extending outside from the opening 31a. , the board 32 and the electronic circuit component 3
The first resin layer 35 is formed up to the vicinity of the opening 31a of the case 31 so as to cover the entire circumference of the first resin layer 3.
5 and a second resin layer 36 formed on the opening 31a to close the opening 31a.

The first resin layer 35 is formed by injecting a predetermined amount of a two-component thermosetting silicone resin to which no colorant or filler is added, and then vacuuming for about 10 minutes at a vacuum degree of about 10 sH ( ) as necessary. Defoaming and removing air bubbles in the injected resin, then
At a predetermined heat curing temperature for a predetermined time (e.g. 30 at 70°C)
The first resin layer 35 is cured to a touch-dry state by heating (see FIG. 1(b)). The second resin layer 36 is based on the same two-component thermosetting silicone resin as the resin used for the first resin layer 35, and this two-component thermosetting silicone resin is filled with fine powder silica. A resin material prepared to have low transparency and high hardness by adding 10 to 100% of the agent by weight is injected onto the first resin layer 35 to a thickness of 5 nm or less. The second resin layer 36 is formed on the first resin layer 35 by performing vacuum defoaming if necessary and further curing to a touch-dry state under the same conditions as for the first resin layer 35. The frontage 31a side is closed and the inside is hidden. Thereafter, the first resin layer 35 and the second resin layer 36 are completely cured by heating at about 150° C. for about 30 minutes, and a finished product hybrid IC 30 is obtained by applying a resin coating using the case potting method. (Figure 1 (
See C).

As described above, the hybrid IC 30 of this first embodiment
In this case, the first resin layer 35 is made of a transparent resin material to which no colorant or the like is added, so it has high insulation properties and remains flexible even after curing, making it reliable due to thermal stress. It is possible to prevent a decline in sexual performance. Furthermore, since the second resin layer 36 is made of an opaque resin material obtained by adding a fine powdered silica filler to the same resin material as the first resin layer 35, the first resin layer 35 is transparent and soft. However, since the second resin layer 36 can hide the circuit configuration on the board 32 inside the case 31, and the high hardness second resin layer 36 closes the opening 31a side of the case 31, it cannot be accessed from the outside. It is possible to prevent effects such as impact on the inside of the case 31. Furthermore, since the first resin layer 35 and the second resin layer 36 have the same resin base, with or without addition of silica filler, the adhesion between them is good and interfacial peeling between them is prevented. There is no risk of curing, and the conditions such as curing temperature and heating time required for curing are almost the same, making it possible to improve the quality of the product.

In the hybrid IC 30 of this embodiment, the second resin layer 36 is exposed from inside the case 31 without being covered with a lid or the like, so the product number, lot number, etc. are written on the surface of the second resin layer 36. Can be marked. In this case, the amount of filler added is adjusted so that the hardness of the second resin layer 36 after hardening becomes a hardness that allows marking, and after being heated and hardened, the second resin layer 36 The surface of 36 is marked using a marking ink by a screen printing method or a stamping method, and after marking, it is further heat-cured at 140° C. to 150° C. for about 2 to 5 minutes.

Furthermore, since the second resin layer 36 is a white silica-based filler, black is suitable for the color of the marking ink, but if necessary, marking can be done with other false-tone inks such as blue or red. good.

Moreover, FIGS. 2(a), (b), and (C) sequentially show the manufacturing process of the hybrid IC of the second embodiment, and the completed hybrid I'C40 (see FIG. 2(C)) is A board 42 is vertically inserted into a case 41 made of hard resin with an opening 41a at the top, and the board 42, on which electronic circuit components 43 are mounted, is arranged parallel to the side wall of the case 41. (See Figure 2(a)) Next, as in the case of the first embodiment, a transparent two-component thermosetting silicone resin to which no coloring agent has been added is injected, and vacuum treatment is performed as necessary. After degassing, the first resin M45 is formed by heating and curing until it is dry to the touch (see FIG. 2(b)).Then, a finely powdered silica-based resin is added to the same resin as the first resin layer 45. A resin material prepared to be opaque and highly hard by adding a filler in an amount of 10 to 100% by weight is injected onto the first resin layer 45, vacuum defoamed if necessary, and then heated. The second resin layer 45 is cured until it is inserted into the finger-touch state.
A resin layer 46 is formed to close the opening 41a side of the case 41 and hide the inside. And after that, about 1
The first resin layer 45 is heated at 50° C. for about 30 minutes:
When both the first and second resin layers 46 are completely cured, the first resin layer 46 is completely cured.
Excellent hybrid IC40 almost the same as in the example
is obtained (see FIG. 2(C)).

However, when the second resin @ 46 and the circuit board 42 are in contact with each other as in the case of the hybrid IC 40 of the second embodiment, the stress of the second resin layer 36 is not directly applied to the circuit board 42. Therefore, it is desirable to minimize the contact area between the two.

FIG. 3 shows a third embodiment of the present invention, in which a pickup coil 52 is housed in a case 51 made of hard resin.
As in both of the above embodiments, the first resin layer 55 is flexible even after curing without the addition of a coloring agent, and the second resin layer 55 is opaque and has high hardness and contains a finely powdered silica filler. 56 shows an electronic component 50 coated with resin coach ink, and the pickup coil 52 inside the case 51 can be effectively protected from external impact and thermal stress.

Furthermore, FIG. 4 shows a fourth embodiment of the present invention, in which a thermistor 62 is housed in a case 61 made of hard resin, and as in the case of each of the embodiments described above, no coloring material is added and it remains flexible even after curing. This figure shows an electronic component 60 coated with a resin by a first resin layer 65 having a high hardness and a second resin layer 66 which is opaque and has high hardness and contains a fine powdered silica filler. , WjI attack from outside,
It can effectively protect against thermal stress.

Note that in each of the above embodiments, a hybrid IC is used.

Although the pickup coil and thermistor have been described, the present invention can also be applied to various other electronic components.

As described in detail, the electronic component of the present invention is an electronic component such as a hybrid IC coated with a resin by the case potting method, in which the potting resin layer covers the first circuit component housed in the case. layer, and a second layer formed on the first layer to close the opening side of the case, and the first layer is made of highly insulating material that does not substantially contain additives such as colorants. The second
The layer was formed of a resin with low transparency and higher hardness than the first layer, in which 10 to 100% of the resin was added with a silica-based filler. After botting, a lid is placed on the case to close the opening, so a gap is formed between the lid and the botting resin, and there is no risk of gas or water entering and accumulating in this gap from the outside world. Furthermore, manufacturing costs can be reduced since there is no need to cover the lid.

Further, since the hard second layer serves as a lid, even if the first layer is flexible, internal circuit components etc. can be effectively protected from external impacts.

Furthermore, since the second layer is made opaque by adding silica-based filler, it is possible to reliably hide the internal circuit structure, etc., and ensure high insulation. It is possible to manufacture highly reliable electronic components without circuit damage, leaks, or malfunctions due to poor electrical insulation, unlike in the case of coloring.

Furthermore, since a silica-based filler is used as the filler, the material cost is lower than that of conventional potting resins, making it possible to reduce the cost of electronic components.

Furthermore, since it can be manufactured using the same manufacturing equipment and manufacturing process as in the case of conventional electronic components such as hybrid ICs, it has the advantage that conventional manufacturing equipment can be used as is.

[Brief explanation of the drawing]

1 to 4 show embodiments of the present invention, and FIGS. 1(a) and 1(c) show the manufacturing process of the hybrid IC of the first embodiment. A) is an explanatory diagram showing the step of disposing the circuit board in the case, FIG. 1(b) is the step of forming the first resin layer, and FIG. 1(C) is the step of forming the second resin layer. Figure 2 (a), (b)
, (c) shows the manufacturing process of the hybrid IC of the second embodiment, where Fig. 2 (a) shows the process of inserting the circuit board into the case, and Fig. 2 (b) shows the process of forming the first resin layer. process,
FIG. 2(C) is an explanatory diagram showing the steps of forming the second resin layer, FIG. 3 is a cross-sectional side view of the electronic component of the third embodiment, and FIG. 4 is a cross-sectional view of the electronic component of the fourth embodiment. The side view, FIG. 5, and FIG. 6 are sectional side views showing examples of conventional electronic components, respectively. 30.40...Hybrid IC, 31,41...
Case, 31a, 41a...opening, 32°42
...Circuit board, 33.43...Electronic circuit parts, 3
5.45... First resin layer, 36.46... Second resin layer, 50... Electronic component, 51... Case, 5
2... Pickup coil, 55... First resin layer, 56... Second resin layer, 60... Electronic component, 6
1...Case, 62...Thermistor, 65...
- 1st resin layer, 66... 2nd resin layer.

Claims (1)

[Claims] In electronic components such as hybrid ICs coated with resin by the case potting method, the potting resin layer includes a first layer that covers the circuit components housed in the case, and a potting resin layer that is formed on the first layer to cover the opening of the case. The first layer is made of a highly insulating resin that does not substantially contain additives such as colorants, and the second layer is made of a silica-based filler. Resin weight 10~
An electronic component characterized in that it is made of a 100% additive resin with low transparency and higher hardness than the first layer.