JPH0468557A - Semiconductor device and molding die thereof - Google Patents

Abstract

PURPOSE:To uniformize the filling speed of resin material in a mold at any area in a package by providing a flow control means which uniformizes the flow of the resin in the package when molding. CONSTITUTION:A lead frame 7 has irregular spaces between inner leads 10 and wide spaces and narrow spaces are mixedly present. In order to fix the spaces, projecting dummy patterns 11 (projecting bodies) are provided as flow control means on the part of the inner leads 10, where wide space is generated. Resin material 5 flows at the same speed at any part by fixing the space between inner leads 10, and since the material does not partly penetrate the lead frame 7 vertically, the resin material 5 flows at the top and bottom of a substrate 2 at the same speed. As a result, no void is generated.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to structural technology and mold technology 1 for packages for semiconductor devices, particularly for use in sealing large substrates on which multi-chips are mounted by transfer molding. It's about techniques that work.

[Conventional technology]

Electronic devices that require higher functionality and smaller size use surface-mounted LSIs (large-scale integrated circuits), but increasing the number of bins increases the package area from several times to several tens of times the chip area. However, there are limits to meeting the demands of equipment manufacturers. Furthermore, as the package size increases, inner leads become longer, stray capacitance and inductance increase, and high-speed operation becomes difficult.

Therefore, multi-chip modules are attracting attention. This is multiple bare LS on a small board (daughter board) etc.
I chips are mounted, and these LSI chips are sealed using various sealing means.

As this sealing means, for example, a plurality of LSI chips are placed on a lead frame pad and then sealed by transfer molding.

Note that this type of technology is described, for example, in "Nikkei Microdevice J, December 1989 issue, pages 32 to 40.

By the way, the present inventor studied the problem of void generation when sealing a multi-chip module by transfer molding.

The following are the techniques studied by the present inventor, and the outline thereof is as follows.

As shown in FIG. 9, the molding process for Sunawachi and multi-chip modules involves disposing a substrate 2 (or tab) on which a plurality of child tubes 1 are mounted in a mold 3, and This is done by injecting the resin material 5 into the mold 3 through the port 4.

[Problem to be solved by the invention]

However, in the package structure in which multi-chip is sealed by transfer molding as described above, there is a difference in the filling speed of the resin material between the upper and lower parts of the mold, or in some parts, as shown in Fig. 9. Then, voids 6 are generated, resulting in a defective product. The inventor has discovered that as a result, the product yield is reduced.

The reason for this is that semiconductor devices have become larger due to multi-chip technology, and as a result, it is necessary to increase the stress on the package, which requires increasing the viscosity of the resin, which makes it difficult for the resin to flow inside the mold. There is a particular thing.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a technique that can make the filling speed of resin material in a mold uniform throughout the entire package.

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

[Means to solve the problem]

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

In other words, it is a semiconductor device in which a semiconductor chip is mounted on a lead frame, its pads are connected to inner leads of the lead frame using bonding wires, and these are molded with resin, and the flow of resin inside the package during molding is A flow regulating means is provided to equalize the flow.

[Effect]

According to the above-described means, the difference in the flow of resin inside the mold during molding between the upper and lower sides of the substrate or the tab, and the difference in speed that occurs locally are reduced. Therefore, the resin filling speed is uniform throughout the package, and no voids are generated.

[Example 1] FIG. 1 is a plan view showing a first embodiment of the present invention.

The lead frame 7 has a lead portion and a mounting area for a substrate 2 on which a semiconductor chip is mounted (the semiconductor chip may be mounted directly on the tab without providing the substrate 2), and has a bonding area on the chip 1. The pad 8 and the lead portion are connected by a bonding wire 9.

Usually, the lead frame 7 has irregular gaps between the inner leads 10. Therefore, the gap is a mixture of wide parts and narrow parts. For this reason, when the resin material 5 is supplied, the flow rate changes partially, which causes voids to occur.

Therefore, in the present invention, in order to make the gap between adjacent inner leads 10 constant, a protrusion-like dummy pattern 11 (protrusion) is provided as a flow regulating means on each inner lead 10 in a portion where conventionally a wide space has occurred. It is designed to have a shape (shaped body). By providing this dummy pattern 11, the gap between the inner leads 10 becomes constant,
No matter where the resin material 5 is wiped, it flows at a uniform speed and does not partially penetrate between the top and bottom of the lead frame 7, and the resin material 5 flows at a uniform speed above and below the substrate 2. As a result, voids 6 as shown in FIG. 7 are not generated.

[Example 2] FIG. 2 is a plan view showing a second embodiment of the invention.

The above embodiment has a dummy pattern 11 on the inner lead 10.
In contrast, this embodiment is characterized in that a protrusion 12 (protrusion) having the same function as the dummy pattern 11 is provided on the substrate 2 (or tab) side.

According to this embodiment, the same effects as in the previous embodiment can be obtained, and the generation of voids 6 can be prevented.

[Embodiment 3] FIG. 3 is a sectional view showing a third embodiment of the present invention. Third
The figure shows a state in which the semiconductor device is cut in the width direction after molding is completed.

This embodiment is characterized in that through holes 13 are provided at multiple locations on the substrate 2 (and tabs). As shown in FIG. 7, the substrate 2 has unevenness on one side because components such as chips are mounted thereon, and the other side is substantially flat. Therefore, the resin material 5 flowing inside the mold 3 is
As described above, the upper side of the substrate 2 is faster and the lower side is slower, and this speed difference generates the void 6.

Therefore, in this embodiment, a through hole 13 (flow regulating means) is provided so that a part of the resin material 5 can flow from the faster side to the slower side. This is to ensure that the flow is uniform. When using this embodiment, each of the above embodiments can also be used in combination.

[Embodiment 4] FIG. 4 is a front view showing a fourth embodiment of the present invention, and FIG. 5 is a plan view thereof.

Since the chip 1 mounted on the substrate 2 is thick, the resin material 5 flowing from the horizontal direction hits the side wall of the chip 1, changes the flow velocity (slows down), and flows around both sides. The resin material 5 flowing on both sides of the chip 1
The flow has slowed down due to the impact.

Therefore, in this embodiment, a groove 14 in the shape of a "F" or "F" is formed in the corner part of the substrate 2 (or tab) on the side wall of the chip 1 perpendicular to the gate opening 4, thereby increasing the resin speed. This is to prevent any changes from occurring. In addition,
As shown in FIG. 5, the grooves 14 are formed on both sides of the gate opening 4. As shown in FIG.

Alternatively, as shown in FIG. 6 (front view) and FIG. 7 (top view), a triangular prism-shaped member is horizontally joined to the corner of the side wall of the chip opposite to the gate opening 4, and A protrusion 15 (flow regulating means) is formed on the.

In the configuration shown in FIG. 6, the resin material 5 flowing from the gate port 4
The liquid rides on the slope of one of the protrusions 15, flows directly over the top surface of the chip 1, and then flows down the other slope. Thereby, rapid speed changes do not occur in the resin material 5, and the flow of the resin material 5 within the mold 3 can be made uniform.

[Embodiment 5] FIG. 8 is a sectional view showing a mold and a semiconductor device according to the present invention in the middle of manufacturing.

Before! In each of the embodiments, only one gate port 4 was provided in the horizontal position, and the resin material 5 was allowed to flow in only from one direction, but as shown in FIG. It is also possible to provide a plurality of gate ports 16 and simultaneously inject from a plurality of locations.

In this way, the moving length of the resin is shortened, the slow speed of the resin is reduced, and the resin material 5 can be flowed at a uniform speed.

The above is a concrete explanation of the invention made by the present inventor based on examples! ! However, it goes without saying that the present invention is not limited to the embodiments described above, and can be modified in various ways without departing from the spirit thereof.

For example, in the above embodiment, a transfer mold was shown, but it goes without saying that the present invention can also be applied to a potting mold.

〔Effect of the invention〕

Among the inventions disclosed in this application, the effects obtained by typical ones are as follows.

In other words, it is a semiconductor device in which a semiconductor chip is mounted on a lead frame, its pads are connected to inner leads of the lead frame using bonding wires, and these are molded with resin, and the flow of resin inside the package during molding is Since the flow regulating means is provided to make the flow uniform, the resin filling speed is made uniform over the entire area within the package, and no voids are generated.

[Brief explanation of the drawing]

1st I! 1 is a plan view showing the first embodiment of the invention, FIG. 2 is a plan view showing the second embodiment of the invention, FIG. 3 is a sectional view showing the third embodiment of the invention, and FIG. 5 is a plan view of the embodiment of FIG. 4, FIG. 6 is a front view of another example of the fourth embodiment, and FIG. 7 is a plan view of the embodiment of FIG. FIG. 8 is a sectional view showing a mold according to the present invention and a semiconductor device in the mold, and FIG. 9 is a sectional view showing how voids occur in a conventional package structure. 1...Chip, 2...Substrate, 3...Mold, 4...
・Gate opening, 5...Resin material, 6...Void, 7.
...Lead frame, 8...Ponding pad, 9
...Bonding wire, 10...Inner lead, 11...Dummy pattern, 12.15...Protrusion, 13...Through hole, 14...Groove, 16...Gate opening. Agent Patent Attorney Daiwa Tsutsui Figure 1 Figure 3 Figure 7

Claims (1)

[Claims] 1. A semiconductor device in which a semiconductor chip is mounted on a lead frame, the pads of the semiconductor chip are connected to inner leads of the lead frame using bonding wires, and these are molded with resin. A semiconductor device characterized by being provided with flow regulating means for uniformizing the flow of resin within a package. 2. The semiconductor device according to claim 1, wherein the flow regulating means is a protrusion provided on a substrate or a tab on which the chip is mounted, or on the inner lead. 3. The semiconductor device according to claim 1, wherein the flow regulating means is a groove or a protrusion provided on a member on which the chip is mounted along both sides of the chip. 4. The semiconductor device according to claim 1, wherein the flow regulating means is provided with a hole passing through the substrate and the tab on which the chip is mounted. 5. A mold for molding a semiconductor device in which a semiconductor chip is mounted on a lead frame, its pads and inner leads of the lead frame are connected with bonding wires, etc., and these are molded with resin, and the resin is injected into the mold. A mold for molding a semiconductor device, characterized by having a plurality of gate openings at the top and bottom for performing the process.