JPH0788901A - Resin sealing mold - Google Patents

Abstract

PURPOSE:To prevent trouble such as the generation of voids or pinholes, non- filling or the like by discharging air to the outside at the time of resin sealing by providing an air vent allowing the air in a cavity to communicate with the outside, the suction passage communicating with the air vent and the suction port communicating with the outside of a mold provided to the suction passage. CONSTITUTION:A mold consists of upper and lower molds and a cavity 1 having a shape conforming to the outer shape of a molded product and the resin inflow passage communicating with the cavity 11 are provided to the upper and lower molds and the pot part 10 communicating with the resin inflow passage is provided to the upper or lower mold. The air vent preventing an inflow resin from flowing out of the cavity 11 and the relay groove 3 and communication groove 4 communicating with the air vent 2 are provided to the outer peripheral part of the cavity 11. The suction port 5 communicating with the outside of the mold is provided to a suction passage and a seal means cutting off the cavity 1, the resin inflow passage, the pot part 10, the air vent 2 and the suction passage from the open air at a part other than the suction port 5 is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin encapsulation mold for encapsulating a semiconductor chip such as an IC with a resin.

[0002]

2. Description of the Related Art As shown in FIG. 3, a conventional resin sealing mold is composed of a pair of upper mold 14 and lower mold 15 which are divided into two parts. In resin encapsulation using this resin encapsulation mold, first, the lead frame 13 on which a semiconductor chip such as an IC is mounted is placed on the lower die 15 and the upper die 14 is covered.
The lead frame 13 is sandwiched and clamped.

Next, the resin previously put into the pot portion 10 of the lower mold 15 is melted by a heating means (not shown) and extruded by applying a pressure by an injection means (not shown). It is made to flow into the cavity 1 via 11. Cavity 1 is lead frame 1
3 corresponds to the semiconductor chip mounting portion, and resin sealing is performed by the resin that has flowed into the cavity 1.

Here, the mold will be described in more detail. FIG. 4 is a partial external view of the lower mold 15. An air vent 2 is provided at the end of the cavity 1 for allowing the air in the cavity 1 to ventilate with the outside with a fine gap of 0.02 mm to 0.04 mm in depth. There is. When the resin is made to flow into the cavity 1, the air in the cavity 1 is discharged to the outside via the air vent 2 to prevent the air from remaining in the cavity 1. If the air remains, the air mixes with the resin, and defects such as voids, pinholes, and non-filling occur in the resin-sealed product. Therefore, for the purpose of discharging air, the larger the cross-sectional area of the air vent 2, the more effective it is. However, since the resin used for resin sealing has high fluidity, the resin also flows out from the air vent 2 when the cross-sectional area of the air vent 2 is increased. Therefore, the depth of the groove of the air vent 2 cannot be about 0.05 mm or more. Therefore, there is a problem that the residual air in the cavity 1 cannot be completely discharged.

In order to solve this problem, Japanese Patent Application Laid-Open No. 64-65861 discloses a structure in which a lead frame is also provided with a ventilation groove and air is exhausted from the groove. In addition, as another method, a dummy cavity is provided following the original cavity, and a dummy molded product is simultaneously molded in the dummy cavity in resin sealing, and residual air is stored in this dummy molded product. Kaisho 64-
No. 89523.

On the other hand, there is a method of forcibly sucking and discharging air from the air vent, but there is a problem that a sufficient effect cannot be obtained because the size of the air vent is small. In order to solve this, as shown in FIG. 5, since the effect cannot be obtained by the forced suction from the air vent, the pot portion 10
Japanese Patent Application Laid-Open No. 61-280910 discloses a structure in which a gas vent hole 102 is provided in the nozzle 1 and air is forcibly sucked from there.

[0007]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
According to the invention described in Japanese Patent No. 861 publication, there is a problem that groove processing is required in the lead frame and the cost becomes high. Further, in the invention described in the above-mentioned Japanese Patent Application Laid-Open No. 64-89523, there is a problem of dummy cavity. However, there is a problem that the area of the mold becomes large.

Further, in the invention described in the above-mentioned JP-A-61-280910, in a multi-plunger type mold having a plurality of pot portions, a plurality of pot portions must be provided with gas vent holes. However, the structure of the mold becomes complicated. Also, with suction from the pot part, the resin in the middle of filling interferes with the air flow, and it is not possible to completely discharge the air in the runner and cavity, so that voids, pinholes, unfilling, etc. from the resin-sealed product. There is a problem that it cannot be completely eliminated.

[0009]

In order to solve the above problems, the resin-sealing mold of the present invention is composed of a pair of molds, an upper mold and a lower mold. A resin having a cavity forming an outer shape of a molded product at a joint portion, a resin inflow passage communicating with the cavity, and a pot portion formed in an upper mold or a lower mold so as to communicate with the resin inflow passage. In the sealing die, an air vent provided on the outer peripheral portion of the cavity for ventilating the air in the cavity with the outside, and a suction passage provided so as to communicate with the air vent (provided to communicate with the air vent A relay groove, a communication groove communicating with the plurality of relay grooves and having a suction port), a suction port provided in the suction passage and communicating with the outside of the mold, the cavity, the resin inflow passage, the pot portion,
The air vent and the suction passage are provided with a shut-off (seal) means that shuts off the air vent and the suction passage so that they do not come into contact with the outside air at portions other than the suction port.

[0010]

The present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view of a resin-sealing die showing an embodiment of the present invention, and FIG. 2 is a partial external view of a lower die 15.

1 and 2, the resin-sealing mold of the present invention comprises a pair of molds, an upper mold 14 and a lower mold 15, and a molded product is formed in the abutting portions of the upper and lower molds. 1, a runner gate 11 that is a resin inflow passage that communicates with the outer peripheral portion of the cavity 1, a pot portion 10 that communicates with the resin inflow passage to inject resin, and an outer peripheral portion of the cavity 1. An air vent 2 for communicating the air in the cavity with the outside, a suction passage provided to the air vent 2, that is, a relay groove 3 communicating with the air vent 2, and a communication groove 4 communicating with the plurality of relay grooves 3. And a suction port 5 for connecting the communication groove 4 and a suction means (not shown) provided outside, for example, a vacuum pump.

Here, the relay groove 3, the communicating groove 4, and the suction port 5 have a sufficient cross-sectional area as compared with the cross-sectional area of the air vent 2 so as not to resist the air flow to be sucked. Air vent 2
Is provided in the outer peripheral portion of the cavity 1, and the same number of relay grooves 3 are provided in communication with the air vent 2 in the outer peripheral portion. The length L of the air vent 2 does not exceed 5 mm. When the length L is short, the resin seal cannot flow out beyond the air vent 2 and dam the resin, but
Even when the length L of the air vent 2 is 5 mm or less, as a result of investigating the damming effect and the degassing suction effect of the resin when the length L is changed, it was found that the effect is sufficient.

Further, the resin-sealing mold of the present invention communicates with a pot portion 10 for injecting a resin, a runner gate 11 as a resin inflow passage, a cavity 1 forming an outer shape of a molded article, and an outer peripheral portion of the cavity 1. Air vent 2 that dams the resin that has flowed in and relay groove 3 that communicates with this air vent 2.
Also, a seal 6 is provided for sealing the resin flow field portion such as the communication groove 4 having the suction port 5 in communication with the plurality of relay grooves 3 and closing them at the time of mold clamping to shut them off from the outside air.

Next, the operation of the resin sealing mold of the present invention will be described with reference to FIGS. 1 and 2.

First, the lead frame 13 on which the IC chip to be resin-sealed is mounted is set in the lower mold. Next, the upper and lower molds are combined and the mold is clamped. Next, the resin previously put into the pot portion 10 formed in the lower mold 15 is melted by the heating means (not shown), and the resin is pushed out by applying a pressure by the injection means (plunger) (not shown). The resin is flowed into the cavity 1 through a cull (not shown) and a runner gate 11 which is a resin inflow passage. The cavity 1 corresponds to the semiconductor chip mounting portion of the lead frame 13, and resin sealing is performed by the resin that has flowed into the cavity 1. At the same time as the resin is pushed out by the injection means, the air inside the cavity 1 is sucked through the air vent 2, the relay groove 3, the communication groove 4 and the suction port 5 by the suction means (a vacuum pump or the like) not shown.
Suction is performed until the cavity 1 is completely filled with the resin.

[0017]

As described above, the mold for resin encapsulation of the present invention has a void in order to suck air from the air vent side together and to reliably discharge the air during resin encapsulation. It is also possible to prevent the occurrence of pinholes, unfilled areas, etc.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a resin sealing mold showing an embodiment of the present invention.

FIG. 2 is a partial external view of a lower die of a resin sealing die showing an embodiment of the present invention.

FIG. 3 is a sectional view showing a conventional resin sealing mold.

FIG. 4 is a partial external view of a lower mold showing a conventional resin sealing mold.

FIG. 5 is a sectional view of a mold described in JP-A-61-280910.

[Explanation of symbols]

 1 Cavity 2 Air vent 3 Relay groove 4 Communication groove 5 Suction port 6 Seal 10 Pot part 11 Runner gate 12 Cull 13 Lead frame 14 Upper mold 15 Lower mold 101 Pot part 102 Gas vent hole

Claims (6)

[Claims] 1. A pair of molds including an upper mold and a lower mold,
A cavity that is provided in the abutting portion of the upper and lower molds and forms the outer shape of the molded product, a resin inflow passage that communicates with this cavity, and an upper die or a lower die that communicates with this resin inflow passage In a mold for resin sealing having a pot portion, an air vent provided in an outer peripheral portion of the cavity for allowing air in the cavity to communicate with the outside, and a suction passage provided so as to communicate with the air vent. ,
A resin-sealing die, comprising: a suction port provided in the suction passage and communicating with the outside of the die. 2. The mold for resin encapsulation according to claim 1, wherein the air vent has a length of 5 mm or less. 3. The mold for resin encapsulation according to claim 1, wherein a plurality of the air vents are provided. 4. The suction passage has a relay groove provided so as to communicate with the air vent, and a communication groove communicating with the plurality of relay grooves and having the suction port. The mold for resin sealing according to claim 1. 5. The blocking means for blocking each of the cavity, the resin inflow passage, the pot portion, the air vent, and the suction passage so as not to come into contact with outside air at portions other than the suction port. 1. The resin sealing mold according to 1. 6. The mold for resin encapsulation according to claim 1, wherein the blocking means comprises a sealing means.