JPS63199619A - Molding equipment and molding method making use of that - Google Patents

Abstract

PURPOSE:To secure an appropriate molding circumstances for packages under all sorts of conditions, by a method wherein a gate and cavity are opened so that they are communicated respectively with both a top and bottom forces of a molding tool. CONSTITUTION:An upper and lower gates 7, 5 are opened respectively on both a recessed position 3a of a top force 1 and a recessed position 3b of a bottom force 2, in a side wall of a cavity 3. As resin 21 to be cast into the cavity 3 is applied in a symmetric form vertically, filling rates at the recessed position 3a of the to force 1 and the recessed position 3b of the bottom force 2 become almost equal to each other. In this instance, as an upper air vent 10 and lower air vent 9 are opened respectively on the recessed position 3a of the top force and the recessed position 3b of the bottom force in the cavity 3, air in the inside of the cavity 3 which has been entrapped by filling of the resin is discharged about equally vertically. Consequently, generation of defects such as an air entrapment phenomenon and a local unfilling phenomenon of the resin is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to molding technology, particularly to improvements in gates in molds. This article relates to materials that are effective for use in transfer molding technology.

[Conventional technology]

In the manufacturing process of semiconductor devices, transfer molding equipment is used to mold resin-sealed pancakes for semiconductor devices.
A lead frame is sandwiched between the upper and lower molds of the mold so that the pellets fit into the inner cavity, and the resin as the molding material is passed through a gate at the end of one side wall of the lower mold cavity. Some devices are configured to mold a package by injecting resin (hereinafter referred to as resin).

In addition, examples of transfer molding technology include:
"Electronic Materials November 1981 Special Edition" published by Kogyo Research Association Co., Ltd., November 10, 1981, P170-P17
There is 5.

[Problem that the invention seeks to solve]

However, in such transfer molding equipment,
Since the gate is disposed on one side wall of the cavity in the lower mold, flat pack packaging (hereinafter referred to as P
In the case of packages that are thin and have different thicknesses on the top and bottom, such as PP, or pancages for sealing large pellets, the upper mold space in the cavity and the lower There is a time difference in filling the resin into the mold space, resulting in air entrainment and non-filling.Also, when the tab suspension lead is long or the tab is large, upward force is generated by the resin. It has been discovered by the inventor that there is a problem in that the tabs and tab suspension leads are irregularly displaced due to the tabs and pellets.

An object of the present invention is to provide a molding technique that can ensure proper molding conditions for packages under all conditions.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Means for solving problems]

An overview of typical inventions disclosed in this application is as follows.

That is, gates are provided in both the upper mold and the lower mold so as to communicate with the cavities.

[Effect]

According to the above-described means, by opening gates in both the upper mold and the lower mold, it is possible to set the resin to fill the upper mold space and the lower mold space simultaneously. Even when the thicknesses of the upper mold space and the lower mold space are significantly different, it is possible to prevent improper molding conditions such as air entrainment and unfilled molding from occurring. In addition, by filling the upper mold space and lower mold space with resin at the same time, the tabs and pellets are equally biased by the force of the resin from above and below. , even if the tabs are large, they will not shift unexpectedly.

[Example 1] Fig. 1 is an exploded perspective view showing a transfer molding apparatus which is an embodiment of the present invention, Fig. 2 is a plan view showing the molding process in progress, Fig. 3 is also a vertical cross-sectional view, and Fig. 4 and FIG. 5 are longitudinal sectional views for explaining the effect thereof.

In this embodiment, this molding apparatus is a semiconductor integrated circuit device (hereinafter referred to as IC) equipped with a PPP.

) is configured to mold a package, and includes an upper mold 1 and a lower mold 2 as molding molds. The upper mold 1 and the lower mold 2 are configured to be mold-matched by a mold clamping device (not shown), and the mating surfaces have recesses 3a and 3b that are approximately square in plan and extend upward and downward into the cavity 3. They are each immersed so that they are constructed cooperatively in the mold. A main runner 4 that communicates with a pot (not shown) is recessed in the mating surface of the lower mold 2 and is arranged parallel to one side of the recess 3b in the vicinity of the recess 3b. A lower gate 5 is provided at the edge of the opening facing the main runner 4 at the edge of the opening at approximately the center of the edge. A sub-runner 6 is recessed between the lower gate 5 and the main runner 4 so as to communicate the two, and the height of the lower gate 5 gradually decreases from the sub-runner 6 side toward the recess 3b side. Its bottom surface is sloped so that

On the other hand, an upper gate 7 is provided at the opening edge of the recess 3a of the upper mold I at a position opposite to the lower gate 5, and an upper sub-runner 8 is provided on the mating surface of the upper mold I. The main runner 4 of the lower die 2 is recessed so as to communicate with the main runner 4 of the lower mold 2. The ceiling surface of the upper gate 7 is inclined so that the height thereof gradually decreases from the sub-runner 8 side toward the recess 3a side.

The lower gate 5 and the upper gate 7 are formed in the recess 3b by appropriately selecting the inclination angle of the bottom surface and the ceiling surface, the dimensional ratio of the opening frontage and opening height, the flow path cross-sectional area ratio, etc.
The correlation between the filling speed of the resin and the recess 3a is substantially equal to each other.

Further, on the mating surface of the lower mold 2, a lower air vent 9 is disposed at the opening edge in the approximate center of the edge of the recess 3b opposite to the edge on which the lower gate 5 is arranged. The upper air vent 10 is arranged on the mating surface of the upper mold 1 so as to align with the lower air vent 9, so that the inside of the recess 3a communicates with the outside air. It was opened in .

On the other hand, the puff cage object 20 includes a lead frame 11 formed into a single plate shape by press punching or the like, and the lead frame 11 includes an outer frame 12 formed in a substantially square frame shape, tab hanging lead 13
a plurality of inner leads 15 arranged radially on four sides surrounding the tab I4; and an outer lead 16 integrally connected to each inner lead 15. , and a dam 17 constructed between adjacent outer leads 16 and 16. A pellet 18 in which an integrated circuit is built is bonded onto the tab 14, and each electrode pad (not shown) of the pellet 18 is connected to an inner lead 1.
5 are electrically connected to each other by bonding wires 19.

Next, a transfold molding method, which is an embodiment of the present invention, using the molding apparatus having the above configuration will be described.

The object to be pancaged 20 is set on the lower mold 2 so that the pellet 18, the inner lead 15 and the bonding wire 19 are aligned with the cavity recess 3b. Subsequently, the upper mold 1 is relatively aligned with the lower mold 2 to form the cavity 3, and the outer frame 12, dam 17, and outer lead 16 of the lead frame 11 are aligned with the upper mold 1.2.
It is sandwiched between the mating surfaces of.

Subsequently, resin 21 is injected into cavity 3 from lower gate 5 and upper gate 7 through main runner 4 and sub-runner 6.8. When the resin 21 is injected, the air inside the cavity 3 is pushed out from the air vent 9.10, and the resin 21 is filled into the cavity 3, thereby molding the package. With this package, the pellet 18, the inner lead 15, and the bonding wire 19 are hermetically sealed.

By the way, as shown in FIG. 4, if the gate 5° is opened only in the lower mold 2 on one side wall of the cavity, the resin injected into the cavity from the gate 5'' will be injected into the lower mold. As a result, upward force F is applied to the tab 14 and pellet 18, causing unexpected displacement of the tab suspension lead 13. As a result, disconnection or short-circuit failure of the bonding wire 19 and short-circuit failure between the tab 14 and the inner lead 15 occur.

Furthermore, in this case, the resin 21 is filled into the upper mold recess 3b after passing through the lower mold recess 3b, so that the resin 21 fills the upper mold recess 3b.
A difference occurs in the filling speed between the upper and lower parts of the mold, and as a result, molding defects such as air entrainment phenomenon and local unfilling phenomenon occur.

However, in this embodiment, since the upper gate 7 and the lower gate 5 are provided in both the recess 3a of the upper mold 1 and the recess 3b of the lower mold 2 in one side wall of the cavity 3, The resin 21 injected into the cavity 3 is filled in a vertically symmetrical manner as shown in FIG. The filling speeds are approximately equal to each other. At this time, since an upper air vent 10 and a lower air vent 9 are provided in the upper mold recess 3a and lower mold recess 3b, respectively, in the cavity 3, the air inside the cavity 3 due to resin filling is approximately It will be discharged evenly.

As a result, defects such as air entrainment and local unfilled resin are prevented from occurring. Also, since the resin is filled evenly on the top and bottom, tab 1
4 and the pellet 1B, and unexpected displacement of the tab suspension lead 13 does not occur. Therefore, there is no possibility of breakage or short circuit of the bonding wire, short circuit between the tab and the inner lead, etc. This will prevent this from occurring.

According to the embodiment described above, the following effects can be obtained.

(By opening an upper gate and a lower gate in the upper mold recess and lower mold recess in the re-cavity, respectively, the filling speed of resin into the cavity can be made approximately equal to each other in the upper mold space and the lower mold space. Therefore, it is possible to prevent improper molding conditions such as air entrainment, local unfilled resin, and unexpected movement of tabs and pellets.

(2) By preventing the occurrence of air entrainment phenomena and local non-filling phenomena of resin, it is possible to suppress the generation of voids inside the package, so that moisture resistance can be improved.

(3) By preventing unexpected movement of the tab suspension lead, tab, and pellet, it is possible to suppress the occurrence of disconnection or short circuit failure of the bonding wire, short circuit failure between the tab and the inner lead, etc.

(4) According to (2) and (3) above, manufacturing yield and product quality and reliability can be improved.

(5) By appropriately selecting the channel cross-sectional area ratio between the upper gate and the lower gate, even when the volume ratio of the upper mold recess and the lower mold recess in the cavity is different, etc. Since the upper and lower resin filling speeds can be made approximately equal, it is possible to create appropriate molding conditions for packages and pellets in response to all molding conditions.

(6) According to (5) above, it is possible to promote high integration and high density of electronic devices by making the pan cage thinner and longer, or increasing the size of the pellet, etc., and also increases productivity. be able to.

[Embodiment 2] FIG. 6 is a second embodiment of a molding apparatus according to another embodiment of the present invention.
FIG. 7 is a plan view corresponding to the figure, and FIG. 7 is a partial vertical sectional view thereof.

In this Example 2, this molding device is a dual-in
This embodiment is configured to mold a resin-sealed package for an IC equipped with a line package (hereinafter referred to as DIP), and the difference from the first embodiment is that resin is sequentially filled through adjacent cavities. The present invention is configured to effectively implement the following molding method (hereinafter referred to as the "through mold method").

That is, a runner 34 is recessed in the mating surface of the lower die 32 and arranged in the direction in which the cavities are lined up, and a lower runner 34 is disposed on the end of the first cavity recess 33b facing the runner 34. A side gate 35 is arranged at the edge of the opening and is opened so as to be connected to the runner 34. On the other hand,
An upper gate 37 is provided at the opening edge of the cavity recess 33 a of the upper mold 31 at a position opposite to the lower gate 35 , and an upper sub-runner 38 is provided on the mating surface of the upper mold 31 . is recessed so as to communicate with the runner 34 of the lower die 32.

Furthermore, a communication path 39 is provided in the first recess 33b- of the lower mold 32 at a position facing the lower gate 35, and is opened to effectively lead out the resin from the cavity. The connecting path 39 is located in the second recess 33b.
is connected to the opposite end of the . Second recess 3
A lower gate 35 is formed at the connection portion of the communication path 39 connected to the cavity 33b with the recess 33b so that the resin sent through the communication path 39 can be effectively injected into the cavity 33. There is.

A communication path 39 is provided at a position opposite to the gate 35 in the second recess 33b so as to effectively lead out the resin from the cavity.
The second recess (not shown) is connected to the opposite position. From then on, the structure is such that this is repeated.

On the other hand, a communication path 40 is arranged in the first recess 33a of the upper mold 31 so as to align with the lower communication path 39, and is opened so as to effectively lead out the resin from the cavity. The communication path 40 is connected to the opposite end of the second recess 33a. An upper gate 37 is disposed at a connection portion with the recess 33a in the communication path 40 connected to the second recess 338 at a position opposite to the lower gate 35 in the recess 33b of the lower mold 32. It is opened so that it can communicate with the tee, and upper gates are similarly opened in the third and subsequent recesses.

In the through-molding method, the resin passes through the first cavity, the second cavity, etc. in order and is filled, so it is necessary to inject a large amount of resin into each cavity. Conceivable.

In this embodiment, 1 is the upper mold recess 33 of each cavity.
Since the upper gate 37 and the lower gate 35 are respectively opened in the a and lower mold recesses 33b, a large amount of resin can be passed through each cavity, and a large amount of resin can be passed through each cavity. You can evenly fill the top and bottom. This results in
Since each cavity is filled with resin under appropriate molding conditions, the through-molding method is effectively realized, and by adopting the through-molding method, productivity can be significantly increased.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the Examples and can be modified in various ways without departing from the gist thereof. Nor.

For example, the upper gate and the lower gate are not limited to being disposed directly facing each other, but may be disposed offset from each other.

The configuration is not limited to a configuration in which the upper gate and the lower gate share a runner, but a configuration in which dedicated runners are connected to the upper gate and the lower gate, respectively.

Upper side? - Means for equalizing the resin filling speed between the upper gate and the lower gate include not only means for adjusting the flow passage cross-sectional area ratio of both gates, but also means for adjusting the flow passage resistance ratio of both gates. , means for adjusting the length ratio of the runners connected to both gates, means for adjusting the ratio of resin supply to both gates, etc. may be used.

It is desirable to equalize the filling vertically by adjusting the flow path cross-sectional area ratio of both gates, etc., for each specific molding condition using an empirical method such as computer simulation or experiment.

The above explanation mainly describes the invention made by the present inventor, the field of application that forms the background of the invention, the molding technology for resin-sealed puff cages for FP-RC, and the molding technology for resin-sealed packages for DIP/IC using the through-molding method. Although the present invention has been described for the case where it is applicable to the above, it is not limited thereto, and can be applied to all molding techniques for resin-sealed packages in other electronic devices.

〔Effect of the invention〕

A brief explanation of the effects obtained by typical inventions disclosed in this application is as follows.

By opening an upper gate and a lower gate in the upper mold recess and lower mold recess in the cavity, the filling speed of resin into the cavity can be made approximately equal in the upper and lower parts, thereby reducing air entrainment. It is possible to prevent the occurrence of improper molding conditions such as local unfilling of the resin, unexpected movement of tabs and pellets, and the like.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view showing a transfer molding apparatus which is an embodiment of the present invention, FIG. 2 is a plan view showing the process of molding, FIG. 3 is a vertical sectional view, and FIGS. 4 and 5 are FIG. 6 is a vertical cross-sectional view for explaining the effect thereof. FIG. 6 shows a second molding apparatus according to another embodiment of the present invention.
FIG. 7 is a plan view corresponding to the figure, and FIG. 7 is a partial longitudinal sectional view thereof. l, 31...upper mold, 2.32...lower mold, 3.33.
...Cavity, 3a, 33a...Upper mold recess, 3b
, 33b...Lower mold recess, 4.34...Main runner, 5.35...Lower gate, 6...Sub runner, 7
．． 37...Upper gate, 8.38...Subrunner,
9, lO... air vent, 11... lead frame, 12... outer frame, 13... tab hanging lead, 14...
...Tab, 15...Inner lead, 16...Outer lead, 17...Dam, 18...Pellet, 19.
... bonding wire, 20 ... object to be pancaged, 21 ... resin, 39, 40 ... connection path.

Claims (1)

[Scope of Claims] 1. A molding device characterized in that an upper gate and a lower gate are respectively opened in the upper mold and the lower mold so as to communicate with the cavity. 2. The molding apparatus according to claim 1, wherein the upper gate and the lower gate are arranged to directly face each other. 3. The molding apparatus according to claim 1, wherein the upper gate and the lower gate are configured to share a runner. 4. The molding apparatus according to claim 1, wherein the upper mold and the lower mold are respectively opened so that the upper air vent and the lower air vent are communicated with the cavity. 5. A plurality of cavities are arranged in the mold, and the rear cavity is communicated with the front cavity by a communication path, and an upper gate and a lower gate are provided at the rear end of these communication paths. 2. The molding apparatus according to claim 1, further comprising: a molding apparatus according to claim 1. 6. Use a molding device in which the upper and lower gates of the upper and lower molds are respectively opened so that they communicate with the cavity, and fill the molding material into the upper mold space and the lower mold of the cavity. A molding method characterized by progressing substantially simultaneously in space. 7. The molding method according to claim 6, wherein the upper gate and the lower gate are configured so that their filling speeds are substantially equal to each other.