JPH03280440A - Molding of semiconductor device using resin - Google Patents

Abstract

PURPOSE:To improve the moldability of a resin and to prevent the generation of a nonfilling, void, wire shift or the like by a method wherein a runner heating temperature is controlled at a temperature lower than the pot heating temperature and the metal mold heating temperature is controlled at a temperature higher than the runner heating temperature. CONSTITUTION:A pot 6 is heated at a conventional heating temperature by heaters 10 and 11 of a molding machine, the parts of runners 4 are heated at a temperature lower than this temperature where the pot 6 is heated and top and bottom forces 1 and 2 are heated at a temperature higher than that where the runners 4 are heated. When an epoxy resin preheated at 80 deg.C, for example, is put in the pot 6, the resin is heated to 175 deg.C, for example, by the heaters 10 and 11 and is brought into a melted state in a time (a). A plunger 7 is forced to descend at a time (b) when a fluidization of the melted resin is proceeding and the melted resin in the pot 6 is press-fed to the runners 4 via paths 12. At this time, as the runners 4 have been heated at a temperature lower than that of the pot 6, the melted state of the resin is made to sustain a state near almost the lowest viscosity. Accordingly, as the injection of a molding material in a metal mold can be smoothly performed taking a long time, there is no possibility of the generation of a nonfilling, void, wire shift or the like and the moldability of the resin is good.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for molding a semiconductor device using a thermosetting resin.

[Prior Art] As is well known, in a semiconductor device, an electrode of a semiconductor chip on which an integrated circuit is formed is connected to each inner lead of a corresponding lead frame, and then an inner lead formed at the tip of each lead is connected. It is integrally molded with thermosetting resin using a molding machine, leaving the outer lead intact. Then, each lead is cut on the outside of the molded resin package, and the leads are appropriately bent as necessary to manufacture a semiconductor device.

FIG. 2 is a schematic diagram showing an example of a transfer molding machine for sealing a semiconductor device, and FIG. 3 is a sectional view taken along line A-A. In the figure, (1) and (2) are an upper mold and a lower mold in which a recess (3) shaped to seal a semiconductor device is formed, and (4)
are the main runners installed in the upper and lower molds (1) and (2), (
5) is a branch runner that communicates the main runner (4) with the fourth part (3). (6) is a pot into which a plunger (7) is inserted, and a cull (8) is formed at the bottom. (1
0) and (11) are the upper and lower molds (1).

(2) is a heater for heating, and (12) is a passageway that communicates the pot (6) with each main runner (4).

Next, the operation of the transfer molding machine configured as described above will be explained. First, open the upper mold (1) and open the lower mold (2).
), and the upper mold (1) is closed. Next, a thermosetting resin consisting of a powder molding material or a solid molding material is preheated to, for example, about 80° C. and placed in the pot (6). At this time, pot (6)
, upper and lower molds (I).

(2), the recess (3) formed in the upper and lower molds (1), (2), the main runner (4), etc.
1) is heated to approximately 175°C. Then, the plunger (7) is pressed down to send the resin, which is already molten in the pot (6), to each recess (3) through the passage (12), the main runner (4), and the branch runner (5). , sealing the semiconductor device.

When the work is finished, the upper mold (1) is opened and each sealed semiconductor device is taken out. Note that there are various shapes and sizes of the sealing portion of the semiconductor device, so if the specifications are different, replace the mold with a corresponding mold.

[Problems to be Solved by the Invention] Various thermosetting resins are used for encapsulating semiconductor devices, and the relationship between the viscosity and time of the most widely used epoxy resin is shown in Figure 4. The curve of A is 17
When heated to 5°C, curve B shows the viscosity when heated to 165°C. In addition, epoxy resin or approximately 100~
It becomes molten at 130°C.

As mentioned above, the conventional transfer molding machine heats the entire machine at the same temperature of approximately 175°C. Therefore, as shown in FIG. 5 derived from FIG. 4, the epoxy resin
It becomes molten at , and is injected between step and c after fluidization has progressed. The injected epoxy resin then begins to harden at time d.

In such molding methods, the molding condition and moldability change significantly depending on the characteristics of the molding material and the conditions of the molding machine, so conventionally the moldability was controlled by adjusting the preheating time and injection speed of the molding material. Was. however,
Recent semiconductor devices are becoming larger, with more bins, ultra-multibins, or larger sizes, which has led to an increase in problems such as unfilled, voided, and wire drift caused by short filling times. There is.

The present invention has been made to solve the above-mentioned problems, and aims to provide a method for molding a semiconductor device that has good moldability and is free from the risk of unfilling, voids, wire flow, etc. .

[Means for Solving the Problems] A method for molding a semiconductor device using resin according to the present invention includes a pot into which preheated molding material is introduced, and a runner through which fluidized molding material pumped from the pot passes. a mold having a plurality of four parts in which a semiconductor device to be encapsulated is disposed and a molding material branched from the runner is injected;
In an apparatus for sealing the semiconductor device with a resin using a molding machine comprising a pot, a runner, and a means for heating the mold, the heating temperature of the runner is controlled to be lower than the heating temperature of the pot, and The heating temperature of the mold is controlled to be higher than the heating temperature of the runner.

[Example] FIG. 1 is a diagram for explaining the present invention in detail, and the present invention will be explained below with reference to FIGS. 2 and 3. In the present invention, a heater (10) of a molding machine.

(11), the pot (6) is heated as before (
For example, 175℃), the runner (4) part has a lower temperature (for example, 165-170℃), and the upper and lower molds (
1) and (2) are at higher temperatures (e.g. 175°C to 1
80°C).

Now, for example, when epoxy resin preheated to 80°C is put into the pot (6), the resin is heated to the heater (to), (
11), it is heated to, for example, 175° C., and becomes molten at time a. And when the fluidization is advanced, the plunger (7
) to direct the molten resin in the pot (6) to the passage (12).
The runner (4) is fed under pressure to the runner (4) through the pot (6).
70℃), the molten state of the resin is
The viscosity changes as shown in the curve in the figure, and the viscosity remains close to the lowest viscosity. As a result, resin can be smoothly injected into the recesses (3) of the upper and lower molds (1) and (2) over time. Since the heating temperature of the upper and lower molds (1) and (2) is again set high (for example, 170 to 180°C), curing starts at time f.

In this way, in the present invention, since the temperature of the runner (4) is set low, a low viscosity state can be maintained for a long time, and therefore the molding time can be extended.

The above explanation shows the case where the semiconductor device is sealed with epoxy resin, but when using other resins, the heating temperature of the runner part is controlled to be lower than the temperature of the pot part, as in the above embodiment, and By controlling the temperature of the mold portion to be higher than the temperature of the runner portion, it is possible to seal the semiconductor device with good moldability.

[Effects of the Invention] As detailed above, the present invention controls the heating temperature of the runner to be lower than the heating temperature of the pot in the process of sealing a semiconductor device using a transfer molding machine, and
The temperature of the mold is controlled to be higher than the heating temperature of the runner,
Since the molding material is kept in a low viscosity state for a long time, the molding material can be smoothly injected into the mold over time. Therefore, it is possible to obtain a method for molding a semiconductor device with good moldability without the possibility of occurrence of unfilling, voids, wire flow, or the like.

[Brief explanation of drawings]

Fig. 1 is a diagram for explaining the present invention, Fig. 2 is a schematic diagram of a transfer molding machine implementing the present invention, Fig. 3 is a sectional view taken along line A-A, and Fig. 4 is a heating temperature of epoxy resin. FIG. 5 is a diagram showing the relationship between viscosity and time, and FIG. 5 is a diagram for explaining conventional injection of molding material. (1) Upper mold, (2): Lower mold, (3): Recess, (4
)・Ranna, (6): Pot, (7) Nibranja, (
10), (11): Heater.

Claims (1)

[Claims] A pot into which preheated molding material is charged, a runner through which fluidized molding material pressure-fed from the pot passes, and a semiconductor device to be sealed is arranged and branched from the runner. In an apparatus for sealing the semiconductor device with a resin using a molding machine comprising a mold having a plurality of recesses into which molding material is injected, and means for heating the pot, runner, and mold, the heating temperature of the runner is A method for molding a semiconductor device using resin, characterized in that the heating temperature of the mold is controlled to be lower than the heating temperature of the pot, and the heating temperature of the mold is controlled to be higher than the heating temperature of the runner.