JPS6216533A - Resin sealing method for semiconductor - Google Patents

Abstract

PURPOSE:To maintain resin in low viscosity when it is poured, to prevent the increase in hardening period of the resin, as well as to prevent with certainty the generation of voids in resin by a method wherein metal molds are heated up at the temperature lower than the preset temperature for hardening the resin, and then the molds are heated up to the preset hardening temperature in the hardening process of resin. CONSTITUTION:A current is applied to a heater 5 by the controlling means 60, with which the temperature of metal molds is set at the preset temperature for hardening resin, by changing the quantity of current to be applied to the heater 5 by the change- over command sent from a change-over time setting means 10. At this point, the resin in a pot is suddenly turned into low viscosity, and the resin is injected into a cavity 4 through the intermediary of a runner 3. At this point of time, as the resin is of low viscosity, the air in the cavity 4 can be removed without fail. The change- over time setting means 10 is operated at this time, and as the command for change of the set temperature is outputted to the controlling means 60, the quantity of current applied to the heater 5 is increased by the controlling means 60, and both metal molds 1 and 2 are controlled in such a manner that they are heated up to 180 deg.C. As a result, the resin can be hardened at the preset hardening temperature in a short period of time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an improvement in a resin encapsulation method for semiconductors.

[Conventional technology]

As a conventional device of this type, the 3rd FI! There were those shown in Figures J to 4. In the figure, +ll is a stopper type, +21
Fi lower mold, (31 is runner, (4) is cavity,
(5) is a heater that is respectively connected to the upper mold (11) and the lower mold (21), and (6) is a control means for controlling the amount and time of energization to the heater (5).

In the configuration as described above, the control means Te
1, the heater (5) is set to a preset energization amount and energization time, and the upper mold (1) and lower mold (2)
are heated at the curing temperature of the resin, for example 180@, respectively,
maintained at that temperature. Here, first, when resin is injected from a pot (not shown, the same applies hereinafter), the resin is injected into the cavity (4) via the runner (3). Thereafter, the resin is cured and the sealing work is completed.

By the way, as shown by the solid line in FIG. 5, the resin located in the pot moves from the runner (3) into the cavity (4) while rapidly decreasing in viscosity. When it reaches 11 hours,
As the resin enters the curing process, its viscosity increases rapidly. In this way, a semiconductor (not shown) is encapsulated.

[Problem that the invention seeks to solve]

However, not only does the resin reach the cavity (4) through a long path from the pot via the runner (31), but also because both molds are heated at the curing temperature of the resin, the resin does not reach the cavity (4) as at point 12. By the time the resin reaches the resin, it has already passed the resin I/'it1 point and has entered the curing process, and the viscosity increases to A2, resulting in insufficient air escape within the cavity (4). This results in the problem that air remains in the cavity (41) and a large number of voids are generated in the resin. Therefore, as a countermeasure for this problem, it is necessary to In order to reduce the viscosity of the resin, both molds (
1), (It is possible to lower the heating temperature in 2j from 180°C to 150°C.

However, in this case, although it is possible to lower the temperature from iA2 at point 12 to A1, since the temperature is lower than the curing temperature of the resin, it takes a long time for curing time, and the quality is poor. There was a problem.

This invention was made in order to solve the above problems, and provides a resin encapsulation method for semiconductors that can maintain low viscosity during injection, prevent increase in curing time, and reliably prevent voids in the resin. It is something.

[Means for solving problems]

The semiconductor resin encapsulation method according to the present invention includes heating a mold at a temperature lower than a predetermined curing temperature of the base resin during the step of injecting the resin into the cavity through the runner;
Next, during the resin curing step, the mold is heated at the predetermined curing temperature.

[Effect]

In the semiconductor resin encapsulation method in this invention, the resin is injected into the cavity while the mold is being heated at a temperature lower than the predetermined curing temperature of the resin, and the air inside the cavity is sufficiently removed. Afterwards, the mold is heated to the above curing temperature of the resin, and the resin is cured in a short time.

[Examples of actual rights to inventions]

Hereinafter, a practical example of this invention will be explained with reference to FIG.

In the figure, the amount of energization to the heater (5) is changed by a switching command from a switching time setting means, aiIfi switching time setting means, which sets the time to switch the amount of energization to the heater (5). The temperature of the mold is set as indicated by the solid line in Figure 2.
This is a control means that sets the resin curing temperature from 150°C to 180°C (predetermined resin curing temperature).

In the structure f'L7: as described above, first,
Control means - heater T5H-J, both molds ill
, [2) is energized to bring the temperature to 150°C.

Here, the resin in the pot is as shown by the dotted line in Figure 2.
The viscosity suddenly decreases, and the resin is injected into the cavity (41) through the runner (3). At time 12, the resin reaches the cavity (4), but at this point, the resin has a low viscosity like As. Since it is in a viscous state, the air in the cavity (4) will be reliably removed.Here, the switching point setting means (lO) is activated and a command for changing the set temperature is sent to the control means. Therefore, the control means increases the amount of current applied to the heater (5) and controls the temperature of both molds (11° (21) to 180°C. Therefore, the resin The resin is cured in a short time at a curing temperature of 180° C. That is, at time point 12, the resin is cured according to a curing curve shown by a dashed dotted line parallel to the solid line in FIG.

〔Effect of the invention〕

As described above, in the process of injecting the resin into the cavity through the runner, the mold is heated at a temperature lower than the predetermined curing temperature of the resin, and in the process of curing the resin. Since the mold is heated to the predetermined curing temperature, the resin can be injected into the cavity at a low temperature without worsening the curing time, and voids in the resin can be reliably eliminated. It has the effect of preventing

[Brief explanation of the drawing]

Figure 1 is a control block diagram showing one embodiment of this invention, and Figure 2 is its temperature and viscosity characteristics. Figure 3 is a sectional view of the conventional device, Figure 4 is its control block diagram, and Figure 5 is the characteristic diagram shown.
The figure shows its characteristic diagram. In the figure, Tll is the upper mold, (2) is the lower mold, (3) the bottom runner, (4) is the capity, (61 is the heater, (1O)
is a switching point setting means, and I is a control means. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] During the process of injecting the resin into the cavity through the runner, the mold is heated at a temperature lower than the predetermined curing temperature of the resin, and during the resin curing process, the mold is heated at the predetermined curing temperature. A resin encapsulation method for semiconductors that heats the mold.