JPH0550132B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a resin-sealed electronic component, and more particularly to a resin-sealed electronic component in which a portion of the resin-sealed body is also formed on the lower surface of a support plate. Relating to a manufacturing method.

BACKGROUND ART AND PROBLEMS TO BE SOLVED There is a resin-sealed semiconductor device in which a portion of a resin-sealed body is also formed on the lower surface of a support plate. This type of semiconductor device has the advantage of being able to be mounted to an external heat sink without using an insulating plate, but in terms of heat dissipation, it is better than a resin-sealed semiconductor device with the bottom surface of the support plate exposed. It is disadvantageous. Therefore,
In order to improve heat dissipation as much as possible, it is necessary to form the resin layer on the lower surface side of the support plate as thin as possible.

In order to form a thin resin layer on the lower surface of the support plate, the support plate is placed at a distance from the bottom of the molding cavity, and the narrow gap formed between the bottom of the molding cavity and the lower surface of the support plate is A sealing resin must be injected inside. For this reason, the sealing resin was not properly injected, resulting in molding defects.

Therefore, in Japanese Patent Application Laid-open No. 60-257529, a downwardly protruding convex portion is provided on the upper surface of the molding cavity, and this convex portion suppresses the flow of the sealing resin toward the upper surface of the support plate. A method of resin molding the device is disclosed. According to this manufacturing method, the flow of the sealing resin toward the lower surface of the support plate can be relatively strengthened, so that the resin layer on the lower surface side of the support plate can be formed relatively well.

By the way, in the above manufacturing method, in order to float the support plate at a predetermined distance from the bottom of the molding cavity during resin molding, the support plate is fixed with pins that protrude into the molding cavity, or supports extending from the support plate are fixed. The support plate was fixed by holding the lead between molds. As a result, pin holes are formed in the completed resin sealing body, and broken surfaces of the support leads are exposed, so that the manufactured semiconductor devices cannot be used in applications requiring severe dielectric strength. Therefore, Japanese Patent Application Laid-Open No. 60-130129 discloses a method of forming a resin-sealed body by fixing a support plate with a movable pin that is provided to freely move forward and backward with respect to a mold. According to this method, the sealing resin can be continuously injected after the movable pin moves, and the sealing resin can also be injected into the void formed after the movable pin moves. It is possible to form a resin-sealed body without

However, it is difficult to control the movement timing of the movable pin, and this is not practical. That is, if the movable pin moves too early, the movable pin will release its hold and the support plate will tilt before the support plate is fixed by solidification of the sealing resin. In addition, if the movable pin is moved too late, the fluidity of the sealing resin around the movable pin will be impaired, and the sealing resin will not be able to be injected into the void that will be shaped after the movable pin is moved, resulting in the pin hole being damaged. There are some difficulties that arise.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method that can solve the above problems and form a thin resin layer on the lower surface of a support plate.

Means for Solving the Problems A method for manufacturing a resin-sealed electronic component according to the present invention includes a support plate having an electronic element fixed to one main surface thereof and an external lead connected to one end side of the support plate. an electronic component assembly having a molding cavity formed therein, a first movable mold, a second movable mold, a second movable mold, and a third movable mold movable with respect to the molding cavity; a step of preparing a molding mold provided with a resin injection port, and holding the external lead between the molding molds and bringing the first movable mold into contact with one main surface on the other end side of the support plate. or close and second
The third movable mold is brought into contact with one main surface on the other end side of the support plate, and the third movable mold is brought into contact with the other main surface on the other end side of the support plate. The distance between the other main surface and the wall surface of the molding cavity facing it is
arranging the electronic component assembly in the mold so that the distance is smaller than the distance between one main surface of the support plate and the wall surface of the molding cavity opposite thereto; The movable molds each block a part of the resin injection port, and the first and second movable molds restrict the injection of resin into the molding cavity on one main surface side of the support plate, while the other side of the support plate is closed. a step of injecting a fluidized sealing resin from a resin injection port into a molding cavity on the main surface side of the support plate, and at least a part of the molding cavity on the other main surface side of the support plate is filled with the sealing resin. After being filled, the first movable mold is moved away from the support plate, and further the sealing resin is injected into the molding cavity from the resin injection port, and the sealing resin injected into the molding cavity is After the support plate is substantially fixed by the above steps, the second and third movable molds are separated from the support plate, and a sealing resin is further injected into the molding cavity from the resin injection port. In the method for manufacturing a resin-sealed electronic component of the present invention, a part of the resin seal is also formed on the other main surface of the support plate, and substantially the entire surface of the support plate is covered with the resin seal. Ru.

Effect According to the present invention, since the flow of the sealing resin toward one main surface of the support plate is controlled by the first and second movable molds, the flow of the sealing resin toward the other main surface of the support plate is controlled. The flow of the sealing resin can be relatively strengthened.
Therefore, the balance between the sealing resin injected onto one main surface side of the support plate and the other main surface side of the support plate is good, and a thin resin layer with no voids etc. is formed on the other main surface side of the support plate. can be formed well. In addition, since the other end side of the support plate is fixed by the second and third movable molds until the support plate is almost fixed by the sealing resin injected into the molding cavity, the sealing resin The tilting of the support plate that occurs during injection can be completely prevented. Further, since a part of the resin injection port is blocked by the second movable mold, and another part of the resin injection port is blocked by the third movable mold, the second and third
The void formed by the movement of the movable mold can be reliably and completely filled with the sealing resin supplied from the resin injection port.

Example FIG. 8 shows a resin-sealed semiconductor device obtained by this example. In this resin-sealed semiconductor device, the entire surface of the support plate is covered with a resin-sealed body 1, and the only exposed metal portion is the external lead 2 led out from the resin-sealed body 1. A method of manufacturing this resin-sealed semiconductor device will be described below.

First, a lead frame assembly 3 as shown in FIG. 7 is prepared as an electronic component assembly. The plurality of support plates 4 of the lead frame assembly 3 and the support plate 4
It has an external lead 2 disposed on one end side.
A semiconductor chip 5 is fixed to one main surface 4a of the support plate 4, and the semiconductor chip 5 and external leads 2 are connected to each other.
are electrically connected to each other by a thin lead wire 6. The external leads 2 are connected in parallel by tie bars 7 and external lead connecting strips 8. Support leads 9 led out from the other end of the support plate 4 are connected in parallel by support lead connection strips 10.

Next, in order to form the resin sealing body 1 by the well-known transfer molding method, as shown in FIG. Place it in When placing the lead frame assembly 3 in the molding die 11, the support leads 9 and the support lead connecting strips 10 are removed in advance. In this embodiment, the lead frame assembly 3 can be handled with the support plate 4 supported on both sides by the external leads 2 and the support leads 9 until just before it is placed in the molding die 11. No deformation occurs.

As shown in FIG.
and a lower mold 13. The upper mold 12 is shown in FIGS. 1 and 2.
As shown in the figure, the cylindrical convex portion 14 and the gate 1
7 and 18, and each runner 15 communicating with the gates 17 and 18, respectively. As shown in FIG. 2, gates 17 and 18 are arranged substantially in parallel. The lower die 13 has a groove 19, a gate 21, and a runner 20 communicating therewith. Further, the molding die 11 of this embodiment has first and second movable dies 23 and 24 which are slidably provided in a guide hole 22 provided in an upper die 12 and are provided in parallel to each other, and a lower die 13.
It has a third movable mold 26 that is slidably provided within a guide hole 25 provided in the. The first, second and third movable molds 23, 24 and 26 are driven by drive devices 27, 28 and 29, respectively.

When the upper mold 12 having the recess 30 and the lower mold 13 having the recess 31 are closed, a molding cavity 32 corresponding to the shape of the resin sealing body 1 is formed in the molding die 11. As shown in FIG.
The lead frame assembly 3 is held between the upper die 12 and the lower die 13 in the fitted state.

Next, the first and second movable molds 23 and 24 are lowered within the guide hole 22 to bring their lower surfaces into contact with one main surface 4a on the other end side of the support plate 4. Further, the third movable mold 26 is raised within the guide hole 25,
The upper surface of the third movable mold 26 is brought into contact with the other main surface 4b on the other end side of the support plate 4. As a result, the other end side of the support plate 4 has the first, second and third movable molds 23,
It is held between 24 and 26. As a result, the support plate 4 is supported at both ends, one end side and the other end side.
The other main surface 4b of the support plate 4 is fixed at a distance L (approximately 0.4 mm) from the bottom surface of the molding cavity 32 throughout. In this embodiment, after closing the upper mold 12 and lower mold 13, the first and second movable molds 23,
24 and the third movable mold 26 were lowered and raised, respectively, but the first, second and third movable molds 23, 2
4 and 26 in advance into the recesses 30 and 31,
After that, the upper mold 12 and the lower mold 13 may be clamped.

Next, a sealing resin 34 that has been slightly softened by high-frequency heating or the like is charged into a pot 33 serving as a resin injection port communicating with the molding cavity 32. The pot 33 and the molding die 11 forming the molding cavity 32 are heated in advance to a temperature at which the sealing resin 34 is softened.
The sealing resin 34 put into the pot 33 is pressed by a plunger 35 that is slidable within the pot 33 and injected into the molding cavity 32.
As is clear from FIGS. 1 and 2, the first and second movable molds 23, 24 are arranged adjacent to the gates 17, 18 communicating with the molding cavity 32, the gates 17, 18 being the first movable molds 23, 24. When the movable mold 23 and the second movable mold 24 are lowered, they are closed, and when they are raised, they are opened. The third movable mold 26 is arranged adjacent to the gate 21 of the molding cavity 32, and the gate 21 is partially closed when the third movable mold 26 is raised.
It opens when it descends.

The second movable mold 24 has a notch 24a and a pair of legs 24b, 24c, and the first movable mold 23 has a second movable mold 24.
The movable die 24 is accommodated in the notch 24a adjacent to the legs 24b and 24c. In addition, the leg portion 24
The side walls b, 24c adjoin the lateral creepage of the molding cavity 32. Similar to the second movable mold 24, the third movable mold 26 has a notch 26a and a pair of legs 26b, 26.
c, and the protrusion 13a of the lower mold 13 is inserted into a part of the notch 26a, as shown in FIG.

As is clear from FIG. 2, the gates 17 and 18 provided on the upper mold 12 are
Located above a. Therefore, when the lower surfaces of the first and second movable molds 23 and 24 are brought into contact with one main surface 4a of the support plate 4, the gate 17
The first movable mold 23 is closed by the leg portion 24b of the movable mold 24 and the first movable mold 23. The gate 18 is the second movable type 2
4 leg portions 24c and the first movable mold 23. Further, the gate 21 provided on the lower mold 13 is located below one main surface 4a of the support plate 4. Therefore, when the upper surface of the third movable mold 26 is brought into contact with the other main surface 4b of the support plate 4, the side portions of the gate 21 are connected to the legs 26 of the third movable mold 26.
b and 26c.

First, second and third movable molds 23, 24, 26
When the sealing resin 34 is pressed with a plunger (push mold) 35 after holding the support plate 4 between the support plate 4 and the sealing resin 34, the sealing resin 34 is removed from the gate 21 which is not blocked by the legs 26b and 26c of the third movable mold 26. is injected into the molding cavity 32 through the inner part of the molding cavity 32. At this time, since the gates 17 and 18 are closed by the first and second movable molds 23 and 24, injection of the sealing resin 34 is prevented. In addition, the other end of the support plate 4 and the molding cavity 30
The space between the sealing resin 34 and the creeping surface can be a passage for the sealing resin 34, but in this embodiment, the upper part of the sealing resin 34 is closed by the lower surfaces of the first and second movable molds 23 and 24, and the injection from the gate 21 is The flow of the sealed sealing resin 33 toward one main surface 4a of the support plate 4 is restricted. Also, one main surface 4a of the support plate 4 is inserted between the side surface of the support plate 4 and the side surface of the molding cavity 32.
The sealing resin 34 is also injected into the side, but the amount is small. Therefore, the sealing resin 34 injected from the gate 21 mainly covers the other main surface 4 of the support plate 4.
Injected into the b side.

After more than half of the molding cavity 32 on the other main surface 4b side of the support plate 4 is filled with the sealing resin 34, the first movable mold 23 is shown in FIGS. 3 and 4. It moves away from the support plate 4 as shown. As a result, approximately half of the gates 17 and 18 are opened, and the gates 17 and 18 are opened with the support plate 4 fixed by the second movable mold 24 and the third movable mold 26.
A sealing resin 34 is injected into one main surface 4a side of the support plate 4 through the support plate 8 . During this time, the sealing resin 34 is also injected from the gate 21.

After almost the entire molding cavity 32 is filled with the sealing resin 34, as shown in FIGS. 5 and 6, a second
Then, the third movable molds 24 and 26 are moved away from the support plate 4. Second and third movable mold 2
4, 26, the legs 24b, 24
A void is created where c, 26b, and 26c are located. Since these spaces are in direct communication with the gates 17, 18, 21, the sealing resin 34 can be reliably injected through the gates 17, 18, 21. After moving the first and second movable molds 23 and 24 in the direction away from the support plate 4 as shown in FIGS. 5 and 6, the lower surfaces of the first movable mold 23 and the second movable mold 24 are The first movable mold 23 and the second movable mold 24 are fixed so as to substantially coincide with the upper surface of the molding cavity 32. Similarly, the sealing resin 34 is injected into the third movable mold 26 with its upper surface substantially aligned with the bottom surface of the molding cavity 32 and the sealing resin 34 is injected therein, so that no step is created in the completed resin-sealed body 1.

This embodiment described above has the following effects.

(1) The second and third movable molds 24 and 26 close part of the gates 17 and 18 and the gate 21, respectively, and the empty spaces formed after the second and third movable molds 24 and 26 move are Gates 17 and 18 respectively
and leads directly to gate 21. Therefore,
Even if the movement timing of the second and third movable molds 24 and 26 is delayed, the sealing resin 34 can be reliably injected into the void.

(2) Until the molding cavity 32 is almost entirely filled with the sealing resin 34, the other end of the support plate 4 is
Since the support plate 4 is held between both sides by the third movable molds 23 and 24, it is possible to reliably prevent the support plate 4 from tilting during resin molding. Therefore, the thickness of the resin layer on the other main surface 4b side of the support plate 4 can be formed to be uniform throughout.

(3) By the first and second movable molds 23 and 24, a good balance is achieved in the injection amount of the sealing resin 34 flowing to one main surface 4a side and the other main surface 4b side of the support plate 4. be able to. Therefore, a thin resin layer can be formed on the other main surface 4b side of the support plate 4 in a good condition without voids, and a good resin sealed body can be formed as a whole.

(4) In this embodiment, the lengths of the flow paths (the length including the runner and the gate) of the plurality of sealing resins 34 extending from the same pot are equal. Therefore, each molding cavity 32 leading to the same pot
Approximately equal amounts of the sealing resin 34 can be injected. Therefore, by measuring the moving distance of the plunger 35, the first, second and third movable molds 23,
24 and 26 can be accurately recognized.

(5) The ratio of the sealing resin 34 injected to the upper surface side and the lower surface side of the support plate 4 can be easily adjusted by changing the movement timing of the first movable mold 23, etc. Therefore, the expensive molding die 11 is suitable for various manufacturing conditions.
can be accommodated without changing the design.

Modifications The above-described embodiments of the present invention can be modified in various ways. For example, the timing for separating the first movable mold 23 from the support plate 4 is approximately 50 mm on the other main surface 4b side of the support plate 4.
% may be before being filled with the sealing resin 34. However, in order to form a good resin layer on the other main surface 4b side of the support plate 4, it is necessary to fill approximately 40% or more of the area on the other main surface 4b side of the support plate 4 before separating the resin layer. desirable. The first movable mold 23 may be slightly spaced apart from one main surface 4a of the support plate 4 from the beginning.

Further, as a movable mold without the connecting portion 24d and the notch portion 24a, the second movable mold 24 may be divided and placed individually on the left and right sides of the first movable mold 23. Further, the first movable mold 23 is placed on one side of the molding cavity 32, and the second movable mold 24 is placed on one side of the molding cavity 32.
It may be placed on the other side of the The first movable mold 23 only needs to be able to restrict the flow of the sealing resin 34 toward the upper surface of the support plate 4, so it does not need to come into contact with the surface of the molding cavity 32. The gates 17 and 18 may include portions located below the extension line of one main surface 4a of the support plate 4. Further, the gate 21 may include a portion located above the extension line of one main surface 4a of the support plate 4. The gates 17, 18, 21 are used only for the upper mold 12 or for the lower mold 13.
It may also be formed only in the form of This can also be easily realized by providing a step between the upper mold 12 and the lower mold 13.

As shown in FIG. 9, the gate 21 (first resin injection port) and the gates 17 and 18 (second resin injection port) may be continuously formed into one gate 16. In this case, the gate 16 has a portion located below one main surface 4a of the support plate 4. Further, the gates 17 and 18 may be completely closed by the second movable mold 24. In this case, the molding cavity 32 on one main surface 4a side of the support plate 4 has a first
A sealing resin 34 is injected from the gate 21 through the cavity formed by the movement of the movable mold 23 .
Further, the side surface of the second movable mold 24 may be spaced apart from the wall surface of the molding cavity 32. In this embodiment, the semiconductor chip 5 as an electronic element is directly fixed to the support plate 4, but the electronic element may be fixed to the support plate 4 indirectly. For example, it is also effective for electronic components in which a circuit board on which electronic elements are mounted or formed is fixed to a support plate.

Effects of the Invention As described above, according to the present invention, in a resin-sealed electronic component in which a part of the resin-sealed body is also formed on the other main surface side of the support plate, the resin-sealed body is formed in a good condition. can.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a molding die for transfer molding equipped with a lead frame assembly in the method for manufacturing resin-sealed electronic components according to the present invention, and FIG. 2 is a sectional view taken along the - line in FIG. 1. , FIG. 3 is a sectional view of the molding die showing the state in which the first movable mold has been moved in FIG. 1, FIG. 4 is a sectional view taken along the - line in FIG. 3, and FIG. A cross-sectional view of the molding die showing a state in which the second movable mold and the third movable mold are moved, FIG. 6 is a cross-sectional view taken along - in FIG. 5, and FIG. 7 is a lead used in the method of the present invention. FIG. 8 is a plan view of a frame assembly, FIG. 8 is a perspective view of a resin-sealed semiconductor device obtained by the present invention, and FIG. 9 is a sectional view of a molding die used in a modified embodiment of the present invention. 1... Resin sealing body, 2... External lead, 3...
Lead frame assembly (electronic component assembly), 4...
... Support plate, 4a... One main surface, 4b... Other main surface, 5... Semiconductor chip (electronic element), 11...
...Molding mold (molding mold), 17, 18...Gate (resin injection port), 21...Gate (resin injection port),
23...first movable type, 24...second movable type,
26... Third movable mold, 32... Molding cavity, 34
...Sealing resin.

Claims (1)

[Claims] 1. An electronic component assembly having a support plate having an electronic element fixed to one main surface and an external lead connected to one end of the support plate, and a molding cavity formed therein. and a molding mold in which first, second, and third movable molds are provided so as to be movable forward and backward with respect to the molding cavity, and a resin injection port having a plurality of or one opening with respect to the molding cavity is provided. and a step of holding the external lead between the molding molds, bringing the first movable mold into contact with or close to one main surface on the other end side of the support plate, and preparing a second movable mold. The movable mold is brought into contact with one main surface on the other end side of the support plate, and the third movable mold is brought into contact with the other main surface on the other end side of the support plate, The distance between the other main surface of the support plate and the wall surface of the molding cavity opposite thereto is smaller than the distance between the one main surface of the support plate and the wall surface of the molding cavity opposite thereto, arranging the electronic component assembly in the mold; closing a portion of the resin injection port with the second movable mold and the third movable mold, respectively; While restricting resin injection into the molding cavity on one main surface side of the support plate by a movable mold, fluidizing the resin from the resin injection port into the molding cavity on the other main surface side of the support plate. and after at least a part of the molding cavity on the other main surface side of the support plate is filled with the sealing resin, the first movable mold is injected into the first movable mold. moving the support plate away from the support plate, and further injecting the sealing resin into the molding cavity from the resin injection port; is substantially fixed, the second
and a step of separating the third movable mold from the support plate and further injecting the sealing resin into the molding cavity from the resin injection port. A method for manufacturing a resin-sealed electronic component, in which a part of the sealing body is formed, and substantially the entire surface of the support plate is covered with the resin sealing body.