JPH09148354A - Die for encapsulating semiconductor with resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the seal performance and moisture resistance by avoiding forming voids or insufficient charging of a resin fed by pressure from a gate formed at one side face into the cavity of a semiconductor device resin encapsulating die. SOLUTION: A gate 17 is disposed at the side face of one of cavities 13 and 14 to feed a resin by pressure into them and air vents 18 and 19 are disposed at this side face and opposite side face thereto to vent air from the cavities. When a resin 27 is injected into the cavities 13 and 14, air is also vented from the vent 18 at the gate side and hence blocked from being involved into the resin at this part where forming of voids or insufficient charging are avoided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor resin sealing mold for resin-sealing a resin-sealed semiconductor device.

[0002]

2. Description of the Related Art All of resin-encapsulated semiconductor devices, which are abbreviated as DIP, TSOP, and SOJ, have a structure in which outer leads are projected only on two opposing side surfaces of a rectangular or square resin package. In a mold for resin encapsulation for manufacturing a semiconductor device of a kind, a resin injection port (hereinafter,
(Referred to as a gate) is arranged. For example, as shown in FIG. 8, the cavity 13 of the lower mold 11
In the mold constituted by the cavity 14 of the upper mold 12, the gate 17 connected to the resin pot 15 via the runner 16 is arranged on a part of the side surface where the outer lead is not arranged, and the side surface facing the side surface. An air vent hole (hereinafter, referred to as an air vent) 19 for removing the air in the cavity is provided in the.

When a semiconductor device is sealed with a resin by using this mold, as shown in FIG. 9A, the lower mold 11 and the upper mold 12 are heated to a desired temperature in advance and the lower mold is used. The lead frame structure 21 is set on 11. The lead frame structure 21 is formed by fixing a semiconductor element 24 on an island 22 of the lead frame 21, and bonding an electrode (not shown in the figure) of the semiconductor element 24e and an inner lead 26 of the lead frame 22 with a bonding wire 25. is there. Then, as shown in FIG. 9B, the resin pot 1
The resin tablet 27 is put into the container 5, the lower mold 11 is raised, and the lead frame structure 21 is clamped, and the mold is clamped.

Next, after the resin tablet 27 is softened by the heat of the lower mold 11, as shown in FIG. 9C, the tablet pressurizing plunger 28 rises, the resin 27 flows through the runner 16, and the cavity A pressure is input into 13 and 14. At this time, the resin 27 passes through the gate 17 and is filled in the cavities 13 and 14 while pushing out the air in the cavities 13 and 14 from the air vent 19 on the opposite side, and as shown in FIG. Is completed. afterwards,
The mold 27 is held in a clamped state until the curing of the resin 27 is completed, and after the curing of the resin 27, the lower mold 11 on the movable side is opened,
An ejector pin (not shown) projects out, and the resin-sealed package is released from the mold to realize resin sealing of the semiconductor device.

At the time of press-fitting the resin, the resin is filled as shown in FIG. 10, but since there is no air vent on the side surface where the gate 17 is present, it is confined in the package corner portion on the side surface where the gate 17 is present. The air loses its escape and is taken into the resin 27 to be molded, resulting in voids in the molded package and poor appearance.

FIG. 11 shows a mold described in Japanese Patent Application Laid-Open No. 3-206629, and here, a lower mold 3 is used.
It is composed of 1, an upper die 32, a split die 33 and three blocks. The lower die 31 has a runner (not shown),
Subrunner 34, lower cavity 3 to be the lower package
5, an air vent 36 is formed, a lead frame guide pin 38 for fixing the lead frame 37, and a guide pin 3 for fixing the split mold 32.
9 are installed respectively. The upper mold 32 is formed with an upper mold cavity 40 that serves as an upper package of the IC and a guide pin escape hole 41. Further, an air vent 42 is formed on the upper surface and the bottom surface of the split mold 33f, and a guide hole 43 and a lead frame guide pin escape hole 44 are respectively penetrated.

In the resin sealing using this mold, the lead frame 37 configured as described above is sandwiched between the upper and lower molds 31, 32 and the split mold 33, and melted by the sub runner 34. The resin is injected into the cavities 35 and 40 of the upper and lower molds. At this time, the resin injected into the cavity separates the air in the cavity from the split mold 33.
The resin is injected into the cavity while being discharged from the air vents 42 formed on the upper and lower surfaces and the air vents 36 formed on the lower mold 31.

[0008]

In the resin encapsulation of the semiconductor element of this type, the molten resin injected from the gate in the resin inflow process proceeds and fills the cavity. In the mold of No. 9, the molten resin has a flow form as shown in FIG. 10, and at this time, the air in the cavities 13 and 14 is naturally exhausted from the air vent 19, but in this mold structure, Since the air vent 19 is provided only at an arbitrary position on the side opposite to the side of the gate 17, the air in the cavities 13 and 14 is not discharged from the side on which the gate 17 is present. Air is entrained in the resin at the cavity corner of the existing side, and this air causes frequent occurrence of voids and unfilling in the resin package, resulting in package sealability and moisture resistance. Cause of the deterioration of the reliability and the like.

Particularly, in recent years, due to thinning of the package, the fluidization of the resin has been increased. However, since the fluidization of the resin increases the air vent burr, the air vent depth of about 30 μ in the past is reduced to 5 μ. Must be: Therefore, the air vent cross-sectional area is about 1
Since the air in the cavity cannot be smoothly exhausted during the resin filling, frequent occurrence of voids and unfilling due to the disturbance of the resin flow pattern are remarkable.

On the other hand, even in the mold disclosed in Japanese Patent Laid-Open No. 3-206629, an air vent is provided in the split mold, but since this air vent is also the facing surface of the cavity when viewed from the gate, You have the same problem as you did. In addition, since the mold is divided into three parts, the mold opening / closing structure of the encapsulating machine becomes complicated, and it is difficult to make the encapsulating machine automatic and compact, and the device cost increases. There is.

The object of the present invention is to effectively discharge the air in the cavity, prevent the air from being entrained in the resin to be molded, prevent the formation of voids and non-filling, and provide sealing and moisture resistance. Another object of the present invention is to provide a mold for encapsulating a semiconductor resin with improved reliability.

[0012]

A semiconductor resin encapsulating mold according to the present invention has a rectangular cavity, and a semiconductor having a gate for pumping resin into the cavity in a part of one side surface thereof. The resin sealing mold is characterized in that an air vent for venting air from the cavity is provided on each of the side surface on which the gate of the cavity is arranged and the opposite side surface facing the gate. The side surfaces facing each other are two side surfaces of the semiconductor device in which outer leads are arranged on two side surfaces of a rectangular package, such as DIP, TSOP, SOJ, etc., on which the outer leads are not arranged. Corresponding to each.

In this case, on one of the side surfaces, the gate is arranged at an intermediate position on the side surface, and air vents are arranged at corners on both sides of the gate. The gate is arranged at one corner of the side surface, and the air vent is arranged at the other corner of the side surface. In addition, the air vent
It is preferable that the one side surface and the side surface facing the one side surface are arranged over substantially the entire area.

[0014]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an example in which the present invention is applied to a resin encapsulation mold of a DIP type resin encapsulation semiconductor device, and (a)
Is a plan view of the lower mold, and (b) is a plan configuration diagram of the upper mold. As shown in FIG. 1, a plurality of cavities 13 and 14 are formed in the respective molds of the lower mold 11 and the upper mold 12, and a resin pot 15 is arranged between the cavities 13 of the lower mold 11. Each cavity 1 through the runner 16
3 is communicated. This cavity 13 and runner 16
The gate 17 for connecting to and is installed at an intermediate position between the two package side surfaces on which the outer leads of the semiconductor device to be resin-sealed are not located and which are closer to the resin pot 15. In addition, the lower mold 11 and the upper mold 12,
The air vents 18 and 19 are provided so as to communicate with the cavities 13 and 14, respectively. Here, the air vents 19 are provided at the package corners on the opposite side surfaces facing the side surface on which the gate 17 is arranged. The air vent 18 is provided at the package corner portion on the side where the gate is arranged.

A step of resin-sealing a semiconductor device using such a die is shown in the sectional view of FIG. First, FIG.
As described above, the upper die 12 and the lower die 11 are heated to a desired temperature in advance, and the lead frame structure 21 is set on the lower die 11. In this lead frame structure 21, a semiconductor element 24 is fixed to an island 23 of a lead frame 22 using silver paste or the like, and an electrode (not shown) of the semiconductor element 24 and an inner lead 26 of the lead frame 22 are bonded by a bonding wire 25. Is bonded.
Then, as shown in FIG. 2B, the resin tablet 27 is put into the resin pot 15, the lower mold 11 is raised, and the lead frame structure 21 is clamped to perform mold clamping.

Next, as shown in FIG. 2C, after the resin tablet 27 is softened by the heat of the lower mold 11, the tablet pressurizing plunger 28 is raised, and the softened resin 27 is discharged from the runner 16. A flow is forced into the cavities 13 and 14. At this time, the resin 27 passes through the gate 17 and pushes out the air in the cavities 13 and 14 from the air vent 19 on the opposite side surface and the air vent 18 on the side surface on the gate 17 side, respectively.
3 and 14 are filled, and the sealing is completed as shown in FIG. After that, although illustration is omitted, the mold is held in a clamped state until the curing of the resin is completed, the lower mold 11 on the movable side is opened after the curing of the resin 27, and the resin-sealed package is ejected by the ejection of the ejector pin. Is released from the mold to realize resin sealing of the semiconductor device.

As described above, in this mold structure, the resin 27 press-fitted into the cavities 13 and 14 discharges the air inside the cavity by the air vent 19 as shown in FIG. Although the air is gradually filled into the inside of the cavity 13 and 14, even if the air in the cavity is trapped in the package corner portion on the side surface on the side where the gate 17 is present, the air vent 18 is also provided on the side surface on the side where the gate 17 is present.
Since air is present, it is possible to prevent voids and non-filling from occurring in the resin to be molded by discharging air from here. Further, by providing the air vents 18 on the gate 17 side as well, the area of the air vents is widened as a whole of the cavity, so that even if the depth of the air vents is made shallow, a wide cross-sectional area of the air vents can be secured, and the air in the cavity is It becomes possible to secure sufficient exhaust efficiency of
It is possible to further enhance the effects described above.

FIG. 4 shows a mold according to a second embodiment of the present invention, wherein (a) is a plan view of the lower mold and (b) is a plan view of the upper mold. Note that parts equivalent to those in the first embodiment are denoted by the same reference numerals. In this embodiment, each of the cavities 13 and 14 has a gate 17 arranged at one corner on the side surface where the outer lead of the semiconductor device is not located. The air vents 19 are provided at both corners of the side surface opposite to the side surface where the gate 17 is provided, and the air vents 18 are provided at the corners adjacent to the gates of the side surface where the gate 17 is arranged. There is.

Also when resin sealing is performed using this die, as shown in FIG. 3, the lower die 11 and the upper die 12 are heated to a desired temperature in advance, and the leads are placed on the lower die 11. The frame structure 21 is set (FIG. 3A). The lead frame structure 21 includes a lead frame 22 and a semiconductor element 24.
Is the same as that of FIG. 1 and is bonded to the inner lead 26 of the lead frame 22 by the bonding wire 25. Then, the resin tablet 27 is put into the resin pot 15, the lower die 11 is raised, and the die is clamped while the lead frame structure 21 is held (FIG. 3B).

Next, after the resin tablet 27 is softened by the heat of the lower die 11, the plunger 28 for pressing the tablet rises, and the resin flows through the runner 16 and is pressed into the cavities 13 and 14. At this time, the resin 27 passes through the gate 17 to allow the air in the cavities 13 and 14 to move to the air vent 1 provided at the corner portion of the opposite side surface.
9 and the air vents 18 provided at the corners of the side surface on the gate 17 side while being extruded, the cavities 13 and 14 are filled and the sealing is completed (FIG. 3).
(C), (d)). After that, the mold is held in a clamped state until the curing of the resin is completed, the lower mold 11 on the movable side is opened after the curing of the resin, and the ejector pin is ejected to release the resin-sealed package from the mold. Realize the resin sealing of the semiconductor device (E).

At this time, in the mold structure of the second embodiment, the resin 27 which is press-fitted into the cavities 13 and 14 is used.
As shown in FIG. 5, while the air inside the cavity is being discharged from the air vent 19, the inside of the cavity is filled from the corner portion of the side surface on which the gate 17 is provided. Even if the air inside the cavities 13 and 13 is trapped in the package corner portion of, since the air vent 18 is provided on the side surface on the side where the gate 17 is present,
By discharging the air from here, it is possible to prevent voids and non-filling of the molded resin.

Here, in each of the molds of the first and second embodiments, as shown in FIGS. 6 and 7, respectively,
The air vents 18 and 19 provided in the lower mold 11 and the upper mold 12, respectively, may be formed not only on the package corners but also on the entire side surface where the outer leads are not present. Therefore, the air vent area in the cavities 13 and 14 becomes large, and the total cross-sectional area of the air vent becomes large.
As a result, the efficiency of exhausting the air in the cavity is increased, and the amount of air entrained is reduced, so that voids and unfilling can be more effectively prevented.

In the above embodiment, the case where the DIP type semiconductor device is resin-sealed has been described as an example.
The present invention can be similarly applied to any semiconductor device such as P and SOJ that is a resin-sealed semiconductor device in which outer leads are provided only on two side surfaces of a rectangular package.

[0024]

As described above, according to the present invention, the DIP,
In a resin-sealed mold of a semiconductor device in which leads are present only on two sides of a rectangle or a square and gates are placed on the sides without leads, such as TSOP and SOJ,
By installing the air vents not only on the side without the gate but also on the side with the gate, it is possible to exhaust the air trapped in the corner of the side with the gate. The efficiency can be increased.
Further, since the area of the air vent in the cavity is wide, even if the depth of the air vent is shallow, the cross-sectional area of the air vent can be widened, and the exhaust efficiency of the air in the cavity can be further enhanced. This makes it possible to prevent voids and non-filling in the resin to be sealed, improving the appearance yield of the resin package and providing a highly reliable semiconductor device.

[Brief description of the drawings]

FIG. 1 is a plan configuration diagram of a mold according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view for explaining a resin sealing process in the first embodiment.

FIG. 3 is a schematic plan view for explaining a resin flow state during resin injection according to the first embodiment.

FIG. 4 is a plan configuration diagram of a mold according to a second embodiment of the present invention.

FIG. 5 is a schematic plan view for explaining a resin flow state during resin injection according to the second embodiment.

FIG. 6 is a plan configuration diagram showing a modified example of the first embodiment.

FIG. 7 is a plan configuration diagram showing a modified example of the second embodiment.

FIG. 8 is a plan configuration diagram of an example of a conventional mold.

9 is a cross-sectional view for explaining a resin sealing step in the mold of FIG.

10 is a schematic plan view for explaining a resin flow state at the time of resin injection of the mold of FIG.

FIG. 11 is an exploded perspective view showing an example of a conventionally known mold.

[Explanation of symbols]

 11 Lower mold 12 Upper mold 13,14 Cavity 15 Resin pot 16 Runner 17 Gate 18,19 Air vent 21 Lead frame structure 24 Semiconductor element

Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical indication // B29L 31:34

Claims (5)

[Claims] 1. A semiconductor resin encapsulating mold having a rectangular cavity, and a gate for pumping resin into the cavity in a part of one side surface of the cavity. An air vent for venting the air in the cavity is provided on each of the side surfaces on the opposite side opposite to the mold for semiconductor resin encapsulation. 2. A metal mold for resin-sealing a resin-sealed semiconductor device, such as DIP, TSOP, SOJ, etc., in which outer leads are arranged on two opposite side surfaces of a rectangular package, said mold comprising: Outer leads are not placed 2
The mold for semiconductor resin encapsulation according to claim 1, wherein a gate is arranged on a part of one side surface of the two side surfaces of the cavity corresponding to each side surface. 3. The semiconductor resin encapsulating mold according to claim 1, wherein the gate is arranged at an intermediate position on the side surface on one side, and air vents are arranged at corners on both sides of the gate. 4. The mold for encapsulating a semiconductor resin according to claim 1, wherein the gate is arranged at one corner of the side surface and the air vent is arranged at the other corner of the side surface. . 5. The mold for encapsulating a semiconductor resin according to claim 1, wherein the air vent is arranged over substantially the entire area of the one side surface and the side surface facing the one side surface.