JPH10144822A - Electronic part mounting substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic part mounting substrate with which generation of the defect such as voids, etc., on sealing resin can be prevented when a resin sealing operation is conducted. SOLUTION: This electronic part mounting substrate consists of a mounting part 3 where an electronic part 30 is mounted, an insulated substrate 2 having a conductive circuit 5 provided around the mounting part 3, and a lead 6 provided protruding to the outside of the insulated substrate 2 in such a manner that it is connected to the conductive circuit 5. A protruding mold ring 1, with which the flow resistance of sealing resin 4 used to seal the electronic part 30 is increased, is provided on the circumference of the insulated substrate 2. When the electronic part 30 is sealed by pouring the sealing resin 4 into a cavity 980 from a gate 981 after fixing an electronic part mounting substrate 81 in the cavity 980 of a sealing metal mold 98, an air release groove 110, which is formed from the inside diameter side to the outside diameter side of the mold ring 1, is provided on a part 11 opposing to a proximity part 12 which comes close to the gate in the mold ring 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate for mounting an electronic component, and more particularly to a structure of a substrate for mounting an electronic component, which prevents generation of voids in a sealing resin for sealing an electronic component with a resin.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG.
It has a mounting section 93 for mounting 0 and a conductor circuit 95 provided around the mounting section 93. The conductor circuit 95 is
It is connected to a lead 96 provided to protrude outward from the insulating substrate 92. A heat radiating plate 97 is adhered to the lower surface of the insulating substrate 92 so as to cover the mounting portion 93. The electronic component 930 mounted on the mounting portion 93 is electrically connected to the conductor circuit 95 by a bonding wire 932. And
After mounting the electronic component 930, the electronic component mounting substrate 9 is sealed with the sealing resin 94.

As a method of sealing an electronic component mounting substrate with a sealing resin, for example, as shown in FIG. 12, a lead is inserted between an upper die 989 and a lower die 988 of a sealing die 98. 96 is pinched and fixed, and the upper mold 989 and the lower mold 988
Then, the electronic component mounting substrate 9 is fixed in the cavity 980 provided between them. A cavity 98 is provided in the mold 98 for sealing.
An air vent 985 for bleeding the air in 0 is provided.

Next, the molten sealing resin 94 is injected into the cavity 980 from the gate 981 which is an injection port of the sealing resin. Thus, the cavity 980 is filled with the sealing resin 94. Thereafter, the mold 98 is removed, and the electronic component mounting substrate 9 sealed with the sealing resin 94 is obtained.

[0005]

However, in the above-mentioned conventional electronic component mounting substrate, the flow of the sealing resin may be partially disturbed during the resin sealing, and defects such as voids may occur. That is, as shown in FIG. 12, when the electronic component mounting substrate 9 is fixed in the cavity 980, the insulating substrate 92 is arranged in the lower portion 980b of the cavity 980. Therefore, the cavity volume of the lower part 980b of the cavity 980 is smaller than the cavity volume of the upper part 980a of the cavity 980. When the heat radiating plate 97 is provided, the cavity volume of the lower portion 980b is further reduced by the volume of the heat radiating plate.

Therefore, the cavity 9 is moved from the gate 981.
When the sealing resin 94 is injected into 80, the flow speed of the sealing resin 94 is lower in the lower part 98b than in the upper part 980a.

Therefore, as shown in FIG.
a, the sealing resin 94 flowing into the lower part 980b
A void may be generated below the electronic component mounting board 9. In particular, voids are likely to occur in the lower portion 941 of the electronic component mounting substrate 9 located at the portion facing the gate 981.

Therefore, conventionally, as shown in FIG. 13, it has been considered to provide a dam ring 91 on the periphery of the electronic component mounting board 9 (Japanese Patent Laid-Open No. 4-215461). As shown in FIG.
Is fixed in the cavity 980 of the mold 98, the flow of the sealing resin 94 flowing through the upper part 980a of the cavity 980 is prevented by the dam ring 91, and the flow velocity of the sealing resin flowing through the upper part 980a and the lower part 980b is reduced. Are equal. Thus, it is possible to prevent the occurrence of voids in the lower part of the electronic component mounting board 9.

However, the conventional electronic component mounting substrate 9
In FIG. 14, as shown in FIG. 14, a ring inner diameter side 919 of an opposing portion located at a portion facing the gate 981 in the dam ring 91 is a portion where the flow of the sealing resin 94 is liable to be disturbed. Therefore, air may be trapped in the ring inner diameter side 919 to generate a void.

In view of the above problems, the present invention is to provide an electronic component mounting board which can prevent defects such as voids from occurring in a sealing resin during resin sealing. is there.

[0011]

According to the first aspect of the present invention, there is provided an insulating substrate having a mounting portion for mounting an electronic component, and a conductor circuit provided around the mounting portion, and an insulating substrate connected to the conductor circuit. In the electronic component mounting substrate, which is formed of leads protruding outward from the substrate, a peripheral portion of the insulating substrate has a convex shape for increasing the flow resistance of a sealing resin for sealing the electronic component. In addition to providing a mold ring, and fixing the electronic component mounting substrate in the cavity of the sealing mold and injecting the sealing resin into the cavity from the gate to seal the electronic component, An opposite part of the ring facing the above-mentioned gate which is close to the gate is provided with a groove for air vent opening from an inner diameter side to an outer diameter side of the mold ring, for mounting electronic parts. On the board .

The operation and effect of the present invention will be described.
In the electronic component mounting substrate of the present invention, a convex mold ring having a groove for venting air is provided on a peripheral portion of the insulating substrate. The air vent groove is provided in an opposing portion facing an adjacent portion that comes close to the gate which is an injection port of the sealing resin.

Since the flow of the sealing resin tends to be stagnant on the inner diameter side of the opposing portion of the mold ring, the flow is likely to be disturbed, and air is entrapped and voids are easily generated. By providing a groove for venting air in the facing portion, air trapped in the sealing resin can escape to the outside of the cavity through the groove. Therefore, according to the electronic component mounting substrate of the present invention, resin sealing can be performed without generating defects such as voids.

Also, by providing a convex dam ring at the peripheral edge of the insulating substrate, the flow resistance of the sealing resin flowing above the cavity is increased. Therefore, the upper portion of the cavity has substantially the same resin flow resistance as the lower portion of the cavity where the flow of the sealing resin is hindered by the insulating substrate. Therefore, almost the same amount of the sealing resin flows in the upper part of the cavity as in the lower part of the cavity.
Therefore, the flow of the sealing resin flowing through the upper and lower portions of the cavity is not disturbed, and no void is generated.

Next, as in the second aspect of the present invention, it is preferable that the groove is provided not only in the opposed portion of the mold ring but also in the adjacent portion. Even in the vicinity of the mold ring close to the gate, voids may be generated due to the disturbance of the flow of the sealing resin. For this reason, by providing a groove for air release also in the proximity part, the generation of voids can be further prevented.

Next, the shape of the mold ring may be any shape as long as it can surround the peripheral portion of the insulating substrate. For example, a polygonal shape such as a square shape or a hexagonal shape, a circular shape, etc. There is. When the mold ring has a polygonal shape, the groove may be provided at any one of the plurality of corners. Further, it is preferable that the mold ring has a quadrangular shape having four corners, and one of the corners is the adjacent portion provided with the groove. This allows air remaining in the inner diameter portion of the ring of the opposed portion to be easily removed from the groove provided in the opposed portion.

In the case where the mold ring has a square shape, the groove is provided not only in the adjacent portion but also in a corner portion adjacent to the adjacent corner portion. Preferably. The reason is the same as in the second aspect of the present invention.

Next, it is preferable that the groove is opened on a side of the mold ring facing the insulating substrate.

This allows air to escape to the outside of the cavity while maintaining a high resistance to the flow of the sealing resin. In addition, voids are likely to occur near the surface of the insulating substrate. Therefore, by providing a groove on the side of the mold ring facing the insulating substrate, air near the surface of the insulating substrate can be easily released from the groove.

Further, as in the sixth aspect of the present invention, the groove may be opened on the side of the mold ring opposite to the side facing the insulating substrate. The mold ring may be provided with an air vent hole penetrating from the inner diameter side to the outer diameter side of the mold ring instead of the air wiping groove. Also in the case where the holes are provided, the same effects as those of the fifth aspect can be obtained.

Next, the ratio of the depth of the groove to the height of the mold ring is 20 to 8 as in the present invention.
It is preferably 0%.

When the ratio of the groove depth is less than 20%,
It is difficult to allow air to escape smoothly, and voids may be generated. On the other hand, if it exceeds 80%,
The flow resistance of the sealing resin in the upper part of the cavity is reduced, and the sealing resin flowing in the upper part of the cavity goes around to the lower part, causing a disturbance in the flow, and a void may be generated in the lower part.

Next, the width of the groove is preferably 0.2 to 2 mm.

If the width of the groove is less than 0.2 mm, it is difficult to allow air to escape smoothly, and a void may be generated. On the other hand, if it exceeds 2 mm, the flow resistance of the sealing resin in the upper part of the cavity becomes low, the sealing resin flowing in the upper part goes around to the lower part, and the flow is disturbed, and a void may be generated in the lower part. There is.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION

First Embodiment An electronic component mounting board according to an embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the electronic component mounting board of the present embodiment has a mounting portion 3 for mounting electronic components and a conductor circuit 5 provided around the mounting portion 3. Is provided. Leads 6 are bonded to the insulating substrate 2 so as to be connected to the conductor circuit 5. One end of the lead 6 is soldered to the conductor circuit 5, and the other end of the lead 6 projects outside the insulating substrate 2. At the periphery of the insulating substrate 2, a convex mold ring 1 for increasing the flow resistance of a sealing resin 4 for sealing an electronic component mounted on the mounting portion is provided.

As shown in FIG. 1 and FIG.
When the electronic component mounting substrate 81 is fixed in the cavity 980 and the sealing resin 4 is injected into the cavity 980 from the gate 981 to seal the electronic component 30, the electronic component 30 comes close to the gate 981 in the mold ring 1. The facing portion 11 facing the adjacent portion 12 is provided with an air vent groove 110 that opens from the inner diameter side to the outer diameter side of the mold ring 1.

As shown in FIG. 5, the mold ring 1
It has a square shape having two corners, and has the same size as the outer dimensions of the insulating substrate 2. Square shaped mold ring 1
Of the four corners of the gate 981
And the proximity part 12 which is close to this. The corners facing the corners close to the gate 981 are formed by the air vent grooves 11.
0 is the opposing portion 11.

As shown in FIGS. 1 and 2, the groove 110 is opened on the side of the mold ring 1 opposite to the side facing the insulating substrate 2. The ratio of the depth of the groove 110 to the height of the mold ring 1 is 50%. The width of the groove 110 is 1 mm. The width of the mold ring 1 is 2 mm.

As shown in FIGS. 1 and 3, the heat radiating plate 7 is bonded to the insulating substrate 2 with an adhesive so as to cover the mounting portion 3 formed of a through hole penetrating the insulating substrate 2. The size of the insulating substrate 2 is 36 mm long, 36 mm wide, and 0.5 mm thick.
mm. The size of the heat sink 7 is 25 mm long and 25 mm wide.
mm and a thickness of 1.5 mm.

As shown in FIG. 4, the electronic component mounting board 81 mounts the electronic component 30 and connects the electronic component 30 and the conductor circuit 5 with each other by the bonding wire 32. Is sealed with the sealing resin 4. The sealing mold 98 is, like the conventional example, the upper mold 9.
89 and a lower mold 988, and a cavity 980 in which the electronic component mounting substrate 81 can be fixed is provided therebetween. The sealing mold 98 includes a gate 981 for injecting the sealing resin 4 into the cavity 980 and a cavity 98.
It has an air vent 985 for removing the air inside 0.

Then, the lead 96 is held and fixed between the upper die 989 and the lower die 988 of the sealing die 98, and the electronic component mounting substrate 81 is fixed in the cavity 980 of the die 98. At this time, the proximity portion 12 of the mold ring 1 is arranged at a position close to the gate 981. Next, the sealing resin 4 melted into the cavity 980 is injected from the gate 981 to fill the cavity 980 with the sealing resin 4. Thereafter, the sealing die 98 is removed, and the electronic component mounting substrate 81 sealed with the sealing resin 4 is obtained.

The operation and effect of this embodiment will be described. In the electronic component mounting board 81 of this example, as shown in FIGS. 1 and 4, a convex mold ring 1 is provided on a peripheral portion of the insulating substrate 2. Since the flow of the sealing resin 4 tends to be stagnant, the flow of the sealing resin 4 on the inner diameter side 119 of the facing portion 11 of the mold ring 1 is likely to be disturbed, and air is entrapped and voids are easily generated.

In this embodiment, the facing portion 11 is provided with a groove 110 for venting air. For this reason, air trapped in the sealing resin 4 through the groove 110 is
80 can escape outside. Therefore, according to the electronic component mounting substrate 81 of this example, resin sealing can be performed without generating defects such as voids.

Also, as shown in FIG. 4, the flow resistance of the sealing resin 4 flowing in the upper portion 980a of the cavity 980 increases by providing the convex mold ring 1 on the peripheral portion of the insulating substrate 2. Therefore, the upper part of the cavity 98
0a has substantially the same resin flow resistance as the lower part 980b of the cavity where the flow of the sealing resin 4 is hindered by the insulating substrate 2 and the radiator plate 7. Therefore, the sealing resin flows through the upper part 980a of the cavity 980 at substantially the same speed as the lower part 980b. Accordingly, the flow of the sealing resin 4 flowing through the upper portion 980a and the lower portion 980b of the cavity is not disturbed, and no void is generated.

Embodiment 2 In the electronic component mounting board of this embodiment, as shown in FIG. 6, the air vent grooves 110 and 120 are formed not only in the facing portion 11 of the mold ring 1 but also in the vicinity 1 of the gate.
2 is different from that of the first embodiment.
The shapes of the grooves 110 and 120 are the same. Other configurations are the same as those of the first embodiment.

At the time of resin sealing, a void may be generated due to disturbance of the flow of the sealing resin also in the proximity portion 12 of the mold ring 1 which is close to the gate 981. Therefore, in the electronic component mounting board 82 of the present embodiment, the air vent groove 12 is also provided in the proximity portion 12.
Therefore, generation of voids can be further prevented.

Embodiment 3 In the electronic component mounting board of this embodiment, as shown in FIG. 7, in addition to the opposing portion 11 and the proximate portion 12 located at the corners of the square mold ring 1, other corners are provided. Part 13,1
4 also has grooves 130 and 140 for venting air.

The shapes of the grooves 110, 120, 130 and 140 are all the same. Others are the second embodiment.
Is the same as In the electronic component mounting board 83 of this example, air vent grooves are provided at all corners of the square mold ring. Therefore, the generation of voids can be more effectively prevented.

Fourth Embodiment In the electronic component mounting board of the present embodiment, as shown in FIG.
It is open on the side facing. The ratio of the depth of the groove 111 to the height of the mold ring 1 is 70%. Groove 1
The width of 11 is 0.5 mm. The width of the mold ring 1 is 1 mm. Other configurations are the same as those of the first embodiment.

In the electronic component mounting board 84 of the present embodiment, as shown in FIG.
It is open on the side facing the insulating substrate 2. Therefore, an air flow path having the integral of the cross section of the groove is formed. In addition, the sealing resin that passes through the upper part 980a of the cavity has an increased resin flow resistance in a narrow resin flow path 4A formed between the upper surface of the mold ring 1 and the inner wall of the cavity 980.

Therefore, according to the present embodiment, air can escape to the outside of the cavity 980 while maintaining a high resin flow resistance. Further, voids are likely to occur near the surface of the insulating substrate 2. Therefore, by providing the groove 111 on the side of the mold ring 1 facing the insulating substrate 2, air near the surface of the insulating substrate 2 can be easily released.

On the other hand, as shown in FIG.
When the air vent groove 110c is opened on the side opposite to the side facing the insulating substrate 2, a space for air vent is formed and the upper part 980a of the cavity 980 is formed.
The cross-sectional area of the resin flow path 4B is enlarged. Therefore, the resin flow resistance may be reduced.

Embodiment 5 In the electronic component mounting board of this embodiment, as shown in FIG.
Are electrically connected through a solder through hole 52 filled with solder 51.

In manufacturing the electronic component mounting substrate 85, first, the mounting portion 3, the conductor circuit 5,
Then, a through hole 52 for solder is formed. The inner wall of the solder through hole 52 is covered with a metal plating film 520.

Next, the tip of the lead 6 is connected to the insulating substrate 2.
Is adhered to and fixed with a resinous adhesive 21. Next, a molten solder bath is arranged below the insulating substrate 2, and the solder is jetted from the solder bath to raise the solder 51 into the through hole 52 for solder. As a result, the solder through hole 52 and the tip of the lead 6 located above the through hole 52 are joined by the solder 51. After that, the heat sink 7 and the mold ring 1 are bonded to the insulating substrate 2 with an adhesive. Thus, the electronic component mounting board 81 is obtained.
Other configurations are the same as those of the first embodiment. Also in this example, the same effect as in the first embodiment can be obtained.

[0046]

According to the present invention, it is possible to provide an electronic component mounting substrate which can prevent defects such as voids from occurring in the sealing resin during resin sealing.

[Brief description of the drawings]

FIG. 1 is a perspective view of an electronic component mounting board according to a first embodiment.

FIG. 2 is a partially enlarged perspective view of an electronic component mounting substrate, showing a groove for air release in the first embodiment.

FIG. 3 is a perspective view of the electronic component mounting board according to the first embodiment as viewed from the back surface side.

FIG. 4 is an explanatory cross-sectional view of the electronic component mounting board fixed in the sealing mold according to the first embodiment.

FIG. 5 is a plan view of the electronic component mounting board, showing a groove forming position in the first embodiment.

FIG. 6 is a plan view of an electronic component mounting board showing a groove formation position in a second embodiment.

FIG. 7 is a plan view of an electronic component mounting substrate showing a position where a groove is formed in a third embodiment.

FIG. 8 is a partially enlarged perspective view of an electronic component mounting board showing a groove formation position in a fourth embodiment.

FIG. 9 is a comparative explanatory view of a groove opened on the side opposite to the side facing the insulating substrate and a groove opened on the side facing the insulating substrate in the fourth embodiment.

FIG. 10 is an illustrative sectional view of an electronic component mounting board according to a fifth embodiment;

FIG. 11 is an explanatory cross-sectional view of an electronic component mounting substrate sealed with a sealing resin in a conventional example.

FIG. 12 is an explanatory view showing a method of sealing an electronic component mounting substrate with a resin in a conventional example.

FIG. 13 is a perspective view of another electronic component mounting substrate in a conventional example.

FIG. 14 is an explanatory view showing a method of sealing another electronic component mounting substrate with a resin in a conventional example.

[Explanation of symbols]

 1. . . Mold ring, 11. . . 11. Opposing part, . . Proximity, 110, 111, 120, 130, 140. . . Groove, 2. . . 2. insulating substrate; . . Mounting part, 4. . . 4. sealing resin; . . 5. conductor circuit, . . Reed, 7. . . Heat sink, 81. . . Electronic component mounting board,

Claims (8)

[Claims] An insulating substrate having a mounting portion for mounting an electronic component, a conductor circuit provided around the mounting portion, and a projection protruding outward from the insulating substrate so as to be connected to the conductor circuit. In the electronic component mounting board comprising the leads provided, a convex mold ring for increasing the flow resistance of the sealing resin for sealing the electronic component is provided on the periphery of the insulating substrate, and When the electronic component mounting substrate is fixed in the cavity of the sealing mold, and the sealing resin is injected into the cavity from the gate to seal the electronic component, the electronic device is close to the gate in the mold ring. An electronic component mounting substrate, characterized in that an air-venting groove that opens from the inner diameter side to the outer diameter side of the mold ring is provided in a facing portion facing the adjacent portion. 2. The electronic component mounting board according to claim 1, wherein said groove is provided not only in said opposed portion of said mold ring but also in said adjacent portion. 3. The mold ring according to claim 1, wherein the mold ring has a quadrangular shape having four corners, and
An electronic component mounting board, wherein one of the corners is the adjacent portion provided with the groove. 4. The electronic component mounting board according to claim 3, wherein the groove is provided not only in the near portion but also in a corner portion adjacent to the corner portion which is the near portion. 5. The method according to claim 1, wherein:
The electronic component mounting substrate, wherein the groove is opened on a side of the mold ring facing the insulating substrate. 6. The method according to claim 1, wherein:
The substrate for mounting electronic components, wherein the groove is opened on a side of the mold ring opposite to a side facing the insulating substrate. 7. The method according to claim 1, wherein:
The ratio of the groove depth to the mold ring height is
An electronic component mounting substrate, wherein the content is 20 to 80%. 8. The method according to claim 1, wherein:
The width of the groove is 0.2 to 2 mm.