JPS6198521A - Molding apparatus - Google Patents

Abstract

PURPOSE:To quicken the return of the lowered temperature of a mold after the completion of transfer to the initial temperature so as to prevent lack of hardening, by providing means for controlling a heater so that the mold temperature after a molding material is transferred to a cavity may be higher than that during the transfer. CONSTITUTION:In a first temperature controller 19, when a first temperature sensor 21 for detecting the temperature near cull 9 detects a temperature below 190 deg.C, a first switch 20 is turned ON, and when a temperature of 190 deg.C or higher is detected, the first switch 20 is turned OFF. In a second temperature controller 22, when a second temperature sensor 24 for detecting the temperature near a cavity detects a temperature below 170 deg.C, a second switch 23 is turned ON, and when a temperature of 170 deg.C or higher is detected, the second switch 23 is turned OFF. A transfer completion switch 25 is located between a relay coil 18 and the first switch 20 and in series with a coil 18 and the first switch 20 but in parallel with the second switch 23, comprises a timer, etc. and is turned ON by a transfer completion detector 26 for a prescribed period after the completion of the transfer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to molding technology, particularly transfer molding technology, and relates to a technology that is effective when used to mold non-hermetically sealed packages, for example, in the manufacture of semiconductor devices. .

[Background technology]

When molding non-hermetically sealed puff cages using transfer molding equipment in the manufacture of semiconductor devices, in order to ensure the transfer of the molten resin as the molding material and the subsequent hardening of the resin, the temperature of the mold is controlled by a heater and a temperature controller. It is conceivable to configure it so that it is controlled constant by.

However, in such transfer molding equipment,
When the size of the puff cage to be molded increases, the temperature of the mold that temporarily drops during resin transfer takes a long time to return to the set temperature after the transfer is complete, resulting in insufficient curing of the package. There is a problem that
revealed by the inventor.

In addition, examples of transfer molding technology include:
"Electronic Materials! November 1983 Special Issue" published by Kogyo Research Association Co., Ltd., November 15, 1983, P151-P15
There is 7.

[Purpose of the invention]

An object of the present invention is to provide a molding technique that can prevent insufficient curing.

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.

[Summary of the invention]

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

In other words, by providing a control means that controls the heater so that the temperature of the mold after the transfer of the molding material is completed to the cavity is higher than during the transfer, the temperature of the mold that temporarily lowered during the transfer after the transfer is complete is provided. This is to speed up the temperature return and prevent insufficient curing.

〔Example〕

FIG. 1 is an enlarged partial sectional view showing a transfer molding apparatus according to an embodiment of the present invention, and FIG. 2 is a circuit diagram showing its heater control means.

In this embodiment, this molding apparatus is configured to mold a non-hermetically sealed package of a semiconductor device,
It includes an upper mold 1 and a lower mold 2.

The upper mold 1 and the lower mold 2 are attached to the plate 3.4 with a heat insulating member 5.
6, and are configured to be clamped together by a mold opening/closing cylinder device (not shown).

The upper mold 1 and the lower mold 2 have center blocks 1a and 2a at the center and cavity blocks Ib and 2b at the periphery.
The center block 1a of the upper mold 1 is formed with a pot 8 into which a plunger 7 for pumping resin as a molding material is inserted, and the center block 2b of the lower mold 2 is formed with a pot 8 into which a plunger 7 is inserted. A cull 9 is formed at a position corresponding to the pot 8. A plurality of cavities 10 are formed on the mating surfaces of the cavity blocks 1b and 2b, and each cavity 10 has a runner 11 and a gate 1.
2 to the Cull 9, respectively.

A plurality of electric heaters 13 are installed inside the upper mold 1 and the lower mold 2.
The heaters 13 are arranged and planted so as to effectively heat the pot 8, the heater 9, and the runner 111 cavity 10, respectively, and this heater 13 is constructed as shown in FIG. The power supply circuit 14 is controlled by the control i circuit 15.

That is, as shown in FIG.
is equipped with a relay 16, and a switch 17 of the relay 16
is interposed in the power supply circuit 14 of the heater so as to open and close it. The coil 18 of the relay 16 has the 11th degree wI
The switch 20 of the temperature controller 19 and the switch 23 of the second temperature regulator 22 are connected in series, and the first switch 2o and the second switch 23 are connected in parallel with each other. The first switch 2o and the second switch 23 are the first temperature sensor 21 and the second temperature sensor 2.
4, and the first temperature sensor 21 is configured to be opened and closed by the second temperature sensor 21 so as to detect the temperature near the temperature sensor 9.
The temperature sensor 24 is disposed inside the lower mold 2 to detect the temperature near the cavity 10.

For example, in the first temperature regulator 19, the first switch 20 is set to turn ON when the first temperature sensor 21 that detects the temperature near the cull 9 detects less than 190°C, and turns OFF when it detects 190°C or more. configured and the second
In the temperature regulator 22, a second switch 23 is configured so that a second temperature sensor 24 that detects the temperature near the cavity is set to 170°C.
It is configured to turn on when it detects a temperature below 170°C, and turn off when it detects a temperature above 170°C.

A transfer completion switch 25 is interposed between the relay coil 1B and the first switch 20, in series with the coil 18 and the first switch 20, and in parallel with the second switch 23. For example, a transfer completion detector 26 consisting of a timer or the like is configured to turn ON for a predetermined period of time after the transfer is completed.

Next, the action will be explained.

When the lead frame 27 of the semiconductor device is positioned on the mating surface of the lower mold 2 so that the pellet 28 and the bonding wire 29 which are the objects to be sealed are accommodated in the cavity 10, the upper mold is opened by the mold opening/closing cylinder device. 1 and the lower mold 2 are combined to form a cavity 10.

When the upper and lower molds 1 and 2 are brought together with a predetermined mold clamping force, the tablets, which are preformed with resin as a molding material and placed in the pot 8, are lowered by a transfer cylinder device (not shown) into the plunger 7. It is pushed out to the runner 11 by. The table left is melted by the heater 13, and the molten resin 31 is transferred through the runner 11 and injected into each of the cavities 10 through the gate 12. When the resin filled in the cavity 10 is further heated, it hardens to form the puff cage 30.

By the way, when molding a large package, it is necessary to slow down the resin transfer speed in order to prevent deformation of the bonding wire. In such a case, it is conceivable to lower the mold temperature and extend the gelation time of the resin.

However, the temperature of the resin at the initial stage of transfer is the mold temperature (for example, 1
Because the temperature is lower (80-90°C) compared to 80°C,
The mold will be cooled by the transferred resin. If the heating ability of the mold by the heater is suppressed, it will take longer for the cooled mold to return to the preset temperature (180°C), which will prolong the curing time of the resin. , insufficient curing will occur.

Therefore, in this embodiment, the heating by the heater is increased to 1!11 to suppress the mold temperature during the transfer and increase it after the transfer is completed.
During the transfer, the resin is kept at a low temperature to suppress the transfer speed, and after the transfer is completed, the heating is increased to shorten the time required for the resin to harden.

That is, before transferring the resin 31, the transfer completion switch 25 is activated.
Since the is turned off, the temperature of the upper and lower molds 1.2 is controlled to 170° C. by the second temperature regulator 22.

When the tablet is put into the pot 8 and the plunger 7 starts transferring the resin, the area around the cull 9 is cooled by the low temperature resin 31, so the first temperature sensor 21 is set at 19.
When a temperature below 0° C. is detected, the first switch 23 is turned on. However, since the transfer completion switch 25 is OFF, the energization to the relay coil 18 is not affected.

When the resin 31 is pumped into the cavity 10, the area around the cavity 10 is cooled, so the second Ili degree sensor 24 detects a temperature below 170°C and turns on the second switch 23.
I will let you do it. When the second switch 23 is turned on, the relay coil 18 is excited, so when the relay switch 17 is turned on, the heater 13 is heated. However, since the second switch 23 is turned off when the second temperature sensor 24 detects a temperature of 170°C or higher, the upper and lower type 15
The temperature of No. 2 will be maintained at 170°C. Therefore, the curing reaction rate of the resin 31 is suppressed,
Deformation of the bonding wire 29 will be prevented.

When the transfer completion detector 26 detects the completion of transfer, the transfer completion switch 25 is turned on, so that the first temperature regulator 19 is connected to the relay coil 18.

At this time, the mold temperature is set to 170°C by the second temperature regulator 22.
Since the temperature is maintained at 190°C, the first temperature sensor 21 is maintained at 190°C.
The first switch 20 is turned on. When the first switch 20 is turned on, the first
Relay coil 1 regardless of the state of temperature controller 22.
8 is excited, the heater 13 is heated by turning on the relay switch 17. In this case, the first switch 20 is configured to turn off when the 11th degree sensor 21 detects a temperature of 190°C or higher, so the heater 13 does not perform rapid heating operation until the mold temperature reaches 190°C or higher. As a result, the resin 31 filled in the cavity 10 is sufficiently heated, thereby preventing insufficient curing.

When the resin 31 is cured, the transfer completion switch 25 is turned off by the transfer completion detector 26, so that the upper and lower molds 1 and 2 are returned to the state where the temperature is controlled by the second IIA degree regulator 22.

Thereafter, the upper and lower molds 1.2 are opened by the mold opening/closing cylinder device, and the semiconductor device whose pellets and the like are sealed by the molded pancage 30 is removed from the cavity 10.

〔effect〕

il+ By providing a control means that controls the heater so that the temperature of the mold after the transfer of the molding material to the cavity is higher than that during the transfer, the temperature of the mold that temporarily lowered during the transfer is reduced after the transfer is completed. Since the temperature return can be accelerated, insufficient curing of the resin can be prevented.

(2) By lowering the mold temperature during transfer, the curing reaction rate of the resin can be suppressed and the transfer speed of the resin can be slowed down, thereby preventing deformation of bonding wires etc. implanted inside the molded product. It can be prevented.

and (3) the control means for controlling the heater includes a first temperature regulator that detects the temperature near the cull of the mold and controls the heater, and a second temperature regulator that detects the temperature near the cavity of the mold. After the transfer of the molding material is completed, the temperature is changed from the first temperature controller to the second temperature! I! By configuring the Ifi+'T device to control the heater, it can be controlled. ■The structure of the means can be simplified.

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 control means for controlling the heater may include a first temperature regulator and a second temperature iji! Not limited to configurations that include an ff device,
The heating capacity of the heater is configured to be variable, and the heating operation is performed at low power during transfer using a detector that detects the completion of transfer.
It may be configured to switch to high power after the transfer is completed.

[Application field]

In the above description, the invention made by the present inventor was mainly applied to a molding apparatus for molding a package in a semiconductor device, which is the background field of application, but the invention is not limited to this. The present invention can also be applied to molding devices for molding other products.

DESCRIPTION OF THE DRAWINGS FIG. 1 is an enlarged partial sectional view showing a transfer molding apparatus according to an embodiment of the present invention, and FIG. 2 is a circuit diagram showing its heater control means.

Claims (1)

[Claims] 1. A heater for heating the mold, and a control means for controlling the heater so that the temperature of the mold after the transfer of the molding material to the cavity is completed is higher than during the transfer. Molding equipment. 2. The control means includes a first temperature regulator that detects the temperature near the cull of the mold and controls the heater, and a second temperature regulator that detects the temperature near the cavity of the mold. 2. The molding apparatus according to claim 1, wherein the control of the heater is switched from the second temperature regulator to the first temperature regulator after the transfer of the material is completed. 3. The heater is configured to have variable heating capacity, and the control means is configured to increase the heating capacity of the heater after completion of transfer compared to during transfer. molding equipment.