JPH02110946A - Manufacture of resin-sealed electronic component - Google Patents

Abstract

PURPOSE:To obtain a method of being able to form favorably a thin resin layer on the side of the lower surface of a supporting plate by using a die for molding use, in which a molding void is formed, first to third movable dies are provided in a design that they can be made to progress or retrogress to or from the void and, moreover, resin injection holes, each having an opening, are provided for the opening place. CONSTITUTION:An electronic component assembly body 3 having a supporting plate 4 with an electronic element 5 fixed on the main surface on one side of it and an outer lead 2 coupled with the side of the end part on one side of the plate 4 and a die 11 for molding use, in which a molding open place 32 is formed, first to third movable dies 23, 24 and 26 are provided in a design that they can be made to progress or retrogress to or from the open place 32 and moreover, resin injection holes 17, 18 and 21 are provided for the open place 32; are prepared. Moreover, the assembly body 3 is arranged in the die 11 and while a resin injection into the open place 32 on the side of the main surface on one side of the plate 4 is limited by the dies 23 and 24, a resin 34 for sealing use is injected in the open place 32 on the side of the other main surface of the plate 4. Then, the dies 23 and 24 are moved in such a way as to become more distant from the plate 4 and moreover, the resin 34 is injected in the open place 32.

Description

[Detailed Description of the Invention] uW Hyosho The present invention relates to a resin-sealed child component, and more specifically, to a resin-sealed child component in which a part of the resin-sealed body is also formed on the lower surface of the support plate. The present invention relates to a method for manufacturing type electronic components.

There is a resin-sealed semiconductor device in which a portion of the resin-sealed body is also formed on the lower surface side of the support plate to be extended. 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 fifth 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 resin layer is placed in the narrow gap formed between the bottom of the molding cavity and the lower surface of the support plate. The sealing resin must be injected into the For this reason, the sealing resin may not be properly injected, resulting in molding defects.

Therefore, Japanese Patent Application Laid-Open No. 60-257529 discloses a semiconductor device in which 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 resin molding method 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 a bottle protruding into the molding cavity, or a support plate extending from the support plate is 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, JP-A-60-130129
The publication discloses a method of forming a resin-sealed body by fixing a support plate with a movable pin that is freely movable in relation 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, making it possible to create a resin-sealed body without pin holes. Can be formed.

However, it is difficult to control the movement timing of the movable pin and 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 space t15 formed after the movable pin is moved. There is a problem with holes.

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

The 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 a support plate connected to one end side of the support plate. An electronic component assembly having an external lead, a molding cavity is formed, and first, second and third movable molds are provided so as to be movable forward and backward with respect to the molding cavity, and a plurality of or one movable mold is provided with respect to the molding cavity. a step of preparing a molding mold provided with a resin injection port having two openings, and sandwiching the external lead between the molding molds, and placing the first movable mold on one main surface on the other end side of the support plate. and the second movable mold is brought into contact with or close to 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 facing it is smaller than the distance between one main surface of the support plate and the wall surface of the molding cavity facing it. As shown in FIG.
The resin was fluidized from the injection port into the molding cavity on the other main surface of the support plate while restricting the injection of resin into the molding cavity on the other main surface of the support plate by the first and second movable molds. After the step of injecting the sealing resin 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, the first movable mold is moved away from the support plate. and then injecting a sealing resin into the molding cavity from the resin injection port, and after the support plate is substantially fixed by the sealing resin injected into the molding cavity, the second and third movable molds are The step of separating the resin from the support plate and injecting a sealing resin 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 side of the support plate, and substantially the entire surface of the support plate is covered with the resin seal.

According to the present invention, since the first and second movable molds suppress the flow of the sealing resin toward one main surface of the support plate, the flow of the sealing resin toward the other main surface of the support plate is suppressed. 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 injection of the sealing resin It is possible to completely prevent the support plate from tilting during the process.

In addition, 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 movement of the second and third movable molds is prevented. It becomes possible to reliably and completely fill the void formed by the sealing resin supplied from the resin injection port.

Fig. 8 shows a resin-sealed semiconductor device obtained in this example. In this resin-sealed semiconductor device, the entire surface of the support plate is covered with the resin sealant (1), and all wings are The exposed portion is only the external lead (2) led out from the resin sealing 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 lead frame assembly (3) includes a plurality of support plates (4) and an external lead (2) disposed at one end of the support plate (4). 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 electrically connected by a thin lead wire (6). The external lead (2) is connected in parallel to the tie "/<- (7) by an external lead connecting strip (8). The support lead (9) led out from the other end of the support plate (4) They are connected in parallel by lead connecting strips (10).

Next, in order to form the resin sealing body (1) by the well-known transfer molding method, the lead frame assembly (3) is placed in a molding die (a mold for transfer molding) as shown in FIG. 11). 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 lead (2) and the support lead (9) until just before it is placed in the molding die (11). , lead frame assembly (3
) does not cause any deformation that would cause problems during the process.

As shown in Figure 1, the molding die (11) has an upper die (12).
and a lower mold (13). As shown in FIGS. 1 and 2, the upper mold (12) has a cylindrical convex portion (14) and a gate (
17) (18) and respective runners (15) communicating with the gates (17) and (18), respectively. As shown in FIG. 2, the 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. Furthermore, the molding die (11) of this embodiment has first and second movable dies (23) that are slidable in the guide hole (22) provided in the upper die (12) and are provided in parallel with each other. (24) and the lower mold (1
3) has a third movable mold (2G) slidably provided in the guide hole (25) provided in the guide hole (25). The PJl, second and third movable molds (23), (24) and (26) are immediately moved by rocking devices (27), (28) and (29), respectively.

When the upper mold (12) having a recess (30) and the lower mold (13) having a 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) is formed within. As shown in Figure 11, the lead frame assembly (3) is assembled with the external lead (2) fitted into the groove (19).
) is held between the upper mold (12) and the lower mold (13).

Next, the first and second movable molds (23) and (24) are lowered in the guide hole (22), and their lower surfaces are aligned with one main surface (4d) on the other end side of the support plate (4). bring it into contact. Also, the third
the 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) is connected to 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, and the other main surface (4b) of the support plate (4) is thin from the bottom surface of the molding cavity (32) throughout. 11J1 interval L (approximately 0.4m
) are fixed apart from each other. In this example, the upper mold (12)
and after closing the lower mold (13).

The first and second movable molds (23) and (24) and the third movable mold (26) were lowered and raised, respectively, but the first and second movable molds
The third movable molds (23), (24), and (26) are made to protrude into the recesses (30) and (31) in advance, and then the upper mold (12) is
) and the lower mold (13) may be clamped together.

Next, the sealing resin (
34) into a pot (33) that serves as a resin inlet leading to 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 poured into the pot (33).
33) by a slideable plunger (35) and injected into the molding cavity (32). As is clear from Figures 1 and 2, the first and second movable molds (23) and (24) are arranged adjacent to the gates (17) and (18) communicating with the molding cavity (32). , the gates (17) and (18) are connected to the first movable type (23) and the second movable type (23).
When the movable mold (24) is lowered, it is closed, and when it is raised, it is opened.

The third movable mold (26) is connected to the gate (2) of the molding cavity (32).
1), a portion of which is closed when the third movable mold (26) is raised, and is opened when the third movable mold (26) is lowered.

The second movable mold (24) has a notch (24a) and a pair of legs (24b) (24c), and the first movable mold (23) has a leg portion of the second movable mold (24). (24b) (24c)
It is housed in the notch (24a) adjacent to. In addition, the side walls of the legs (24b) (24c) have molding cavities (32).
adjacent to the lateral creepage of.

Similar to the second movable mold (24), the third movable mold (26) has a notch (26a) and a pair of legs (26b) and (26c), and a part of the notch (26a) has a As shown in FIG. 1, the protrusion (13a) of the lower mold (13) is inserted.

As is clear from Fig. 2, the gates (17) and (18) provided on the north type (12) are located on one main surface of the support plate (4) (
It is located above 4a). For this reason, the first and second
When the lower surfaces of the movable molds (23) and (24) are brought into contact with one main surface (4a) of the support plate (4), the gate (17)
It is closed by the legs (24b) of the second movable mold (24) and the first movable mold (23). Gate (18) is the second
The legs (24c) of the movable mold (24) and the first movable mold (2
3) is blocked by In addition, the gate (21) provided on the lower mold (13) is connected to one main surface (
It is located below 4a). 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 attached to the third movable mold (26). ) are closed by the legs (26b) (26c).

First, second and third movable molds (23) (24) (26)
After holding the support plate (4) between the two, when the sealing resin (34) is pressed with a plunger (push mold) (35), the sealing resin (34) is pressed against the leg part of the third movable mold (26). (26b) (2
6c) into the forming cavity (32) through the inner part of the gate (21) which is not closed. At this time, the gates (17) and (18) are connected to the first and second movable molds (23).
(24), the injection of the sealing resin (34) is blocked. Further, the gap between the other end of the support plate (4) and the creeping surface of the molding cavity (30) can become a passage for the sealing resin (34), but in this embodiment, the upper part of this gap is the first
and a sealing resin (33) closed by the lower surfaces of the second movable molds (23) (24) and injected from the gate (21).
The flow toward the first main surface (4a) of the support plate (4) is restricted. In addition, the side surface of the support plate (4) and the molding cavity (32)
The sealing resin (34) is also injected into one main surface (4a) side of the support plate (4) through the gap between the sealing resin (34) and the side creeping surface of the support plate (4), but the amount thereof is small. Therefore, the sealing resin (34) injected from the gate (21) is mainly injected into the other main surface (4b) side of the support plate (4).

After more than half of the void space on the other main surface (4b) of the support plate (4) is filled with the sealing resin (34), the first movable mold (23) is shown in FIGS. 3 and 4. Support plate (4) as shown
). This allows the gate (
17) (18) is about half open, and the support plate (4) is the second
The support plate (
A sealing resin (34) is injected onto one main surface (4a) side of 4). During this time, the sealing resin (
34) is injected.

After almost the entire molding cavity (32) is filled with the sealing resin (34), the second and third movable molds (24) and (26) are supported as shown in FIGS. 5 and 6. Move away from the plate (4). Second and third movable molds (24) (2
6) by moving the legs (24b) (24c) (
26b) A void is created at the location where (26c) is located. Since these spaces are in direct communication with the gates (17), (18), and (21), the sealing resin (34) can be reliably injected through the gates (17, 18, and 21). As shown in FIGS. 5 and 6, after moving the first and second movable molds (23) and (24) in the direction away from the support plate (4), the first movable mold (23) and the second movable mold (23) and 2 movable types (2
4) Fix the first movable mold (23) and the second movable mold (24) with their lower surfaces substantially aligned with the upper surface of the molding cavity (32).

Similarly, the third movable mold (26) has its upper surface covered with the molding cavity (3).
Since the sealing resin (34) is injected while being fixed almost in line with the bottom surface of 2), there will be no step in the completed resin sealing body (1).

This embodiment described above has the following effects.

(1) The second and third movable molds (24) (26) close part of the gates (17) (18) and the gate (21), respectively, and the second and third movable molds (24) ( The voids formed after the movement of gates (17) and (1
8) and directly to the 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 space.

(2) Almost the entire molding cavity (32) is covered with the sealing resin (34).
) until the other end of the support plate (4) is filled with the second
and the third movable mold (23) (24), so that the support plate (4) is held in a state of being held on both sides by the third movable mold (23) (24).
It is possible to reliably prevent the slope of the Therefore, the support plate (4)
The thickness of the resin layer on the other main surface (4b) side can be formed uniformly over the entire surface.

(3) The first and second movable molds (23) and (24) are connected to one main surface (4a) side and the other main surface (4a) side of the support plate (4).
The injection amount of the sealing resin (34) flowing to the b) side can be well balanced.

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 into. Therefore, the moving distance of the plunger (35) is measured and the first. Second and third movable molds (23) (24) (26
) movement time can be accurately recognized.

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

Strange-” [-Kai Various modifications can be made to the above-described embodiments of the invention.

For example, the time to separate the first movable mold (23) from the support plate (4) is approximately 500 mm on the other main surface (4b) side of the support plate (4).
0% may be before being filled with the sealing resin (34). However, in order to form a good resin layer on the other soil surface (4b) side of the support plate (4), approximately 40% or more of the area on the other main surface (4b) side of the support plate (4) must be It is preferable to fill it up and then separate it. 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 part (24d) and the notch (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 arranged on one side of the molding cavity (32), and the second movable mold (24) is arranged on the other side of the molding cavity (32). Good too. First movable type (23)
Since it is sufficient to restrict the flow of the sealing resin (34) toward the upper surface side of the support plate (4), it is not necessary to bring it into contact with the creeping surface of the molding cavity (32). The gates (17) and (18) may include a portion located below the extension line of one main surface (4a) of the support plate (4).

Further, the gate (21) is connected to one main surface (4) of the support plate (4).
It may include a portion located above the extension line of a). The gates (17), (18), and (21) are connected to the upper mold (12).
) or only on the lower mold (13). 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) are successively connected to one gate 1-(16) resin. It may also serve as an injection port. In this case, the gate (16) has a portion located below one main surface (4a) of the support plate (4).

In addition, the gates (17) and (18) are connected to the second movable type (24).
It may be completely occluded by In this case, the molding cavity (32) on the one main surface (4a) side of the support plate (4) is filled with the gate (21) for sealing through the cavity formed by the movement of the first movable mold (23). Resin (34) is injected. In addition, the side surface of the second movable mold (24) has a molding cavity (
32) may be separated from the wall surface. In this embodiment, the semiconductor chip (5) as an electronic element is directly fixed to the support plate (4).
It may be indirectly fixed to. For example, it is also effective for electronic components in which a circuit board on which electronic elements are mounted or formed is supported and temporarily fixed.

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 kept in a good state. can be formed into

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a molding die for a 1-transfer mold equipped with a lead frame assembly in the method for manufacturing a resin-sealed electronic component according to the present invention, and FIG.
3 is a sectional view of the molding die shown in a state in which it has moved with the first movable mold in FIG. 1; FIG. 4 is a sectional view taken along line nn in FIG. 3; 5 is a cross-sectional view of the molding die showing the state in which the first movable mold and the third movable mold have been moved in FIG. 3, FIG. 6 is a cross-sectional view along the line ■-■ in FIG. The figure is a plan view of a lead frame assembly used in the method of the present invention, FIG. 8 is a perspective view of a resin-sealed semiconductor device obtained by the present invention, and FIG. 9 is a molding used in a modified embodiment of the present invention. It is a sectional view of a mold. (1), Resin molding body, (2), External lead,
(3) Lead frame assembly (electronic component assembly)
, (4), , Support plate, (4a) , . One principal surface, (4, b), the other principal surface, (5
)0. Semiconductor chip (electronic device), (11),
. Molding mold (molding mold), (17) (18),. Gate (resin injection port), (21), Gate (resin injection port), (23), First movable mold, (24)
),, second movable type, (26),, third movable type,
(32),, molding cavity, (34). , sealing resin, patent applicant: Sanken Electric Co., Ltd. Agent: Yo Shimizu (and others) Figure 6 Figure 7 Figure 9 Figure 8

Claims (1)

[Scope of Claims] An electronic component assembly comprising a support plate having an electronic element fixed to one main surface thereof, an external lead connected to one end of the support plate, and a molding cavity formed therein. A molding mold in which first, second, and third movable molds are provided so as to be movable toward and away from the molding cavity, and a resin injection port having a plurality of or one opening with respect to the molding cavity is provided. 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 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 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 part of the resin injection port with the second movable mold and the third movable mold, respectively; A seal fluidized from the resin injection port into the molding cavity on the other main surface side of the support plate while restricting resin injection into the molding cavity on the one main surface side of the support plate by a movable mold. and after at least a portion of the molding cavity on the other main surface side of the support plate is filled with the sealing resin, moving the first movable mold away from the support plate. and further injecting the sealing resin into the molding cavity from the resin injection port, and after the support plate is substantially fixed by the sealing resin injected into the molding cavity, Said 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.