JPH0430182B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a semiconductor resin encapsulation apparatus used for manufacturing semiconductor devices such as various integrated circuits.
In particular, it relates to mold structure.

[Technical background of the invention]

First, in order to understand the present invention, a description regarding a semiconductor sealing device will be given.

There are various types of molds for semiconductor resin encapsulation devices, and each type is classified mainly based on the press-fitting structure of the resin. That is, the difference is whether the resin is press-fitted into the cavity from the upper mold side or by pushing it up from the lower mold side. In addition, from the viewpoint of productivity, it is common to use one mold to resin-seal multiple semiconductors at the same time, but there are also molds in which a predetermined number of cavities are molded into a group from one injection pot through a runner. There is a type in which resin is supplied to a plurality of cavity parts, and a so-called multi-pot type in which a plurality of combinations of pots are arranged between a pair of left and right cavity parts. The runner type is superior to the multi-pot type in terms of productivity because it can simultaneously seal a large number of resins, but the multi-pot type is superior in terms of quality. This is because in the multi-pot type, the pots and cavities are close to each other, so the press-fitting pressure of the resin is applied uniformly to each cavity part.

Here, an outline of a conventional multi-pot mold is shown in FIG. 1, and details are shown in a sectional view in FIG. First, as shown in Figure 1, the molds are an upper mold 1 and a lower mold 2.
These are used by stacking them on top of each other. A plurality of left and right cavity portions 3A are arranged in one direction in the lower mold 2, and a resin press-fitting pot 4 is provided between each cavity portion 3A. On the other hand, each cavity part 3 of the lower mold 2 is attached to the upper mold 1.
Cavity parts 3B corresponding to A are provided, and from each cavity part 3A, when the upper mold 1 and the lower mold 2 are overlapped, a pot 4 and a cavity part 3 are formed.
Resin introduction paths (hereinafter referred to as gate portions) 5 communicating with A and 3B are provided, respectively.

In FIG. 2, a plunger 6 is provided within the pot 4 and moves back and forth in the axial direction thereof, that is, moves up and down. When press-fitting the resin 7, use the plunger 6.
Lower the tablet to a predetermined position, insert the tablet into the empty space in pot 4, and then lower the upper mold 1.
and the lower mold 2 are placed one on top of the other, and heated at a predetermined temperature to press-fit the melted resin by pushing up the plunger 6. A tablet is a tablet formed into, for example, a cylindrical shape so that resin can be poured into the pot 6 in advance. Powdered resin may be used instead of a tablet.
When the plunger 6 is pushed up, the molten resin flows into the pot 6.
from each cavity portion 3A, 3 via the gate portion 5.
It is press-fitted into B. After a predetermined period of time, the resin is thermoset, and the semiconductor devices previously housed in the cavities 3A, 3B are sealed with the resin, completing the molding.

Next, the upper mold 1 is removed, and the cured device is pushed up by an eject pin (not shown) provided in the cavity part 3A of the lower mold 2 side or the part corresponding to the gate part 5, and then carried to the next step by an appropriate conveyance means. Transport to.

[Problems with background technology]

An example of the chip formed as described above (before separation and cutting) is shown in FIG. In FIG. 3, 8 indicates each chip, and 9 indicates a lead frame. The left and right chips 8 are kept connected to each other by a gate 10 formed by the gate portion 5 of the upper mold 1 and a cull 11 formed corresponding to the pot 4. In this state of the chip, it is the cull 11 that becomes a problem.

That is, as mentioned above, after the resin is cured, it is released from the mold and transported. In order to maintain the connected state in which each chip 8 is integrated during this transport, the cull 11 must have a predetermined mechanical strength. It is required to have. Also, when releasing from the mold, Cal 11
If the separation between the plunger 6 and the plunger 6 is not smooth, there is a risk of damage. For this reason, the Cull 11 is normally required to have a thickness of about 1 mm.

On the other hand, in order to perform resin sealing economically and to shorten the time required for curing to shorten the molding cycle time, it is conceivable to reduce the thickness of the cull 11. However, as mentioned above, making the cull 11 thinner does not guarantee the required mechanical strength.

On the other hand, when trying to speed up the molding cycle time while keeping the Cull 11 thick (for example, when increasing the molding cycle time by 20 to 30 seconds), the Cull 11 that is the last to solidify during the curing process of the resin 7 may be in an uncured state. Then, mold release is started, and the mold is damaged by mold release force from the mold, etc., and as a result, it is not possible to smoothly transport it to the next process, making it impossible to speed up the molding cycle time.

The above becomes noticeable when the diameter of the cull increases as the tablet becomes larger due to the larger chip size, leading to an increase in resin efficiency and curing time, leading to a decrease in productivity. .

Next, FIGS. 4 and 5 show a mold having a structure different from the above mold. That is, in the example shown in FIG. 2, the plunger 6 stops at a position slightly lower than the interface between the upper die 1 and the lower die 2, and therefore the gap between the interface and the tip surface of the plunger 6 is Cull 11 will be formed. In other words, the cull 11 remains in the pot 4 at the end of molding. As described above, the fact that the cull 11 remains in the pot 4 causes mold release failure when the mold is released from the lower mold 2 using the eject pin, and in severe cases, the gate part may break and chips manufactured at the same time may be damaged. The integrity is not lost, and as a result, transportation to the next process is hindered.

Therefore, at the end of the press-fitting of the resin, the tip of the plunger 6 is pushed into the upper mold 1 side rather than the interface between the upper and lower molds, so that the resin of the cull 11 does not remain in the pot 4, and the force acting at the time of mold release is prevented. The configuration shown in FIGS. 4 and 5 is such that the data is erased. Reference numeral 12 indicates a cull recess for forming the cull 11. Although such a structure has the above-mentioned advantages, it is necessary to increase the cull 11 by the thickness that the plunger 6 enters, so the gate portion 5 must be made thicker by that amount. And the problems mentioned above still remain.

[Purpose of the invention]

Therefore, the present invention provides a resin encapsulation device for a semiconductor element, which takes into account productivity such as resin efficiency and molding cycle time, and can secure the required mechanical strength without making the cull thicker than necessary. The purpose is to

[Summary of the invention]

In order to achieve the above object, a semiconductor resin encapsulation device according to the present invention uses a multi-pot type runnerless mold having a plunger for advancing and retracting inside a resin injection pot and press-fitting resin into a cavity. In the sealing device, a recess along the shape of the protrusion for forming a reinforcing protrusion that rises perpendicularly or slightly inwardly to at least one of the upper and lower surfaces of the molded cull; It is characterized in that it is provided on at least one of the bottom surface of the cull portion of the mold or the tip surface of the plunger.

[Embodiments of the invention]

Embodiments of a semiconductor resin sealing device according to the present invention will be described below based on the drawings.

FIGS. 6 and 7 show the structure of a mold according to the present invention. FIG. 6 shows a pair of cull recesses 12 and cavities 3B and 3A of the upper mold 1, and FIG. 7 shows a longitudinal section of the upper and lower molds combined. Note that the same parts as in FIGS. 1 to 5 will be described with the same reference numerals.

As shown in FIGS. 6 and 7, a recess 13 is formed in the cull recess 12 so that a protrusion (not shown) is formed on the upper surface of the cull 11 after molding. Although the shape of the recess 13 is cross-shaped in the example shown in FIG. 6, it may also be formed radially around the center of the recess 13, such as an X-shape or a star shape. In this way, by providing the recess 13, a protrusion is formed on the cull 11 that increases its cross-sectional thickness, making it possible to resist shear stress and bending stress applied to the cull during demolding and transportation. . Moreover, even if the protrusions are provided in this way, the resin efficiency will not deteriorate. In other words, the thickness of the cull 11 itself can be reduced.

In the above example, the recess 13 is formed in the cull recess 12 of the upper mold 1, but the recess 13 may be formed in the tip end surface of the plunger 6. In that case, there is a concern that the mold release between the plunger 6 and the cull 11 will be poor, but this can be resolved by tapering the corner portions of the recess 13 to form a shape that facilitates mold release.

Furthermore, especially when using a large tablet, a recess 13 is provided on both the cull recess 12 and the tip end surface of the plunger 6 in order to form protrusions not only on one side of the cull 11 but also on both the upper and lower surfaces for reinforcement. It's okay.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to form a reinforcing ridge on at least one of the upper and lower surfaces of the cull after molding, which effectively increases the cross-sectional thickness and reinforces the cull. Therefore, the required mechanical strength can be ensured without increasing the cull thickness more than necessary. Moreover, since the protrusions are vertical or stand up with a slight inclination, release from the mold is good and transportation to the next process can be carried out smoothly.

This makes it possible to improve resin efficiency, shorten molding cycle time, and improve productivity.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing a first example of a conventional general mold, Fig. 2 is a partial vertical sectional view thereof, Fig. 3 is a plan view showing the connected state of chips after molding, and Fig. 4 is a perspective view showing a first example of a conventional general mold.
The figure is a plan view showing the shape of a recess in a part of the upper mold in a second example of a conventional mold, FIG. 5 is a partial longitudinal cross-sectional view of the same mold, and FIG. FIG. 7 is a plan view showing the shape, and a partial vertical sectional view of the mold according to the present invention. 1...Upper mold, 2...Lower mold, 3A, 3B...Cavity, 4...Pot, 5...Gate, 6...Plunger, 7...Resin, 11...Cull, 12...
Cal recess, 13... recess.

Claims (1)

[Scope of Claims] 1. In a semiconductor resin encapsulation device using a multi-pot type runnerless mold having a plunger for advancing and retracting inside a resin injection pot to press-fit resin into a cavity, To form a reinforcing protrusion that rises perpendicularly or slightly inwardly to at least one surface of the lower surface, a recess along the shape of the protrusion is formed on the bottom surface of the cull portion of the mold or on the plunger. 1. A semiconductor resin encapsulation device, characterized in that the device is provided on at least one of its tip surfaces. 2. In the device according to claim 1,
The plunger is a semiconductor resin sealing device characterized in that its tip is pushed into the opposite side of either the upper mold or the lower mold beyond the boundary line between the upper mold and the lower mold. Stop device. 3. A semiconductor resin encapsulation device according to claim 1 or 2, wherein the recess is cross-shaped. 4. A semiconductor resin encapsulation device according to claim 1 or 2, wherein the recess is X-shaped. 5. A semiconductor resin encapsulation device according to claim 1 or 2, wherein the recess is star-shaped.