JPS6142416B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resin sealing device for semiconductor devices using upper and lower matching molds.

A conventional resin sealing device of this type is shown in FIGS. 1 and 2. That is, in these FIGS. 1 and 2, numerals 1 and 2 are upper and lower mold blocks, and 3 and 4 are heaters for heating these upper and lower mold blocks and measuring the temperature, respectively. and a thermocouple are attached to the upper and lower heat blocks; 5 and 6 are upper and lower platens that hold the mold through the respective heat blocks; 7 is fixed to the main body base 8 and moves the lower platen 6 up and down. 9 is a transfer cylinder for pressurizing the molded resin, and 10 is a guide post that is set up on the main body stand 8 to fix the upper platen 5 at the upper end and guide the lower platen 6.

In the case of this conventional configuration, each mold block 1 and 2 facing each other is connected to a respective heat block 3,
4, and with the lead frame constituting the semiconductor device loaded on the upper surface of the lower mold block 2, the mold cylinder 7 is operated to clamp each mold block 1 and 2, and then the transfer is performed. The thermosetting resin is pumped from the cylinder 9 to perform resin sealing molding. Incidentally, the heating temperature of each of the mold blocks 1 and 2 depends on the type of molding resin, but is generally around 180°C, and the pressure for pumping the thermosetting resin is similarly about 50 kg/cm ² . .

Here, an example of the shape of each of the mold blocks 1 and 2 is as shown in FIG.
The gap L ₁ for fitting is usually about 0.01 to 0.05 mm, and the distance L ₂ from the center of the mold to the end is often about 200 to 300 mm. Furthermore, materials such as SKD-11 or SKD-12 are generally used for the molds 1 and 2 due to their wear resistance, maintaining high precision, and low distortion due to heat. The coefficient of thermal expansion of the material is approximately 115×10 ^-7 .

Conventionally, resin sealing is performed by such means, but during molding, each mold block 1 and 2 expands depending on the thermal expansion coefficient of the material due to heating, and usually Since they are heated to the same temperature, there is no problem in fitting the upper and lower molds together. In addition, the heating temperature of each of these molds 1 and 2 is normally controlled by a closed-loop automatic control system using thermocouples for temperature measurement attached to the heat blocks 3 and 4, ensuring accurate and stable set temperatures. keeping.

Therefore, if the temperature control system is operating normally, there will be no particular problem, but if an abnormality such as heater breakage or control system failure occurs, the upper and lower mold blocks 1,
A difference occurs between the heating temperatures of the two, and as a result, the gap _L1 may disappear due to the difference in the amount of thermal expansion. In other words, let's take an example and calculate it. First, L ₁ = 0.02mm, L ₂ = 200mm, upper mold temperature T ₁ = 160
℃, lower mold temperature T ₂ = 180℃, temperature difference = 20deg, thermal expansion coefficient K = 132 × 10 ^-7 , lt = thermal expansion amount of L ₂ end at t℃, Upper mold lt ₁ = K・L ₂・T ₁ = 132×10 ^-7 ×200×160
=0.4224 Lower mold lt ₂ =K・L ₂・T ₂ =132×10 ^-7 ×200×180
=0.4752 Thermal expansion difference Δlt=lt ₂ −lt ₁ =0.4752−0.4224=
0.0528 Change in gap L ₁ = L ₁ −Δlt=0.02−0.0528=−
In this calculation example, the gap L ₁ = 0.02mm changes to 0.0328mm by overlapping, and if you try to fit the two mold blocks together in this state, you may end up with cracks or cracks in the overlapped part. There is a risk of damage occurring.

The present invention has been made to improve these conventional drawbacks, and one embodiment of the present invention will be described in detail below with reference to FIGS. 3 and 4.

FIG. 3 shows a mold temperature difference detection block to which this embodiment is applied, and FIG. 4 shows a detection panel.

In these figures 3 and 4, reference numeral 1
1 indicates a temperature difference detection circuit, and the upper and lower heat blocks 3 and 4 have thermocouples 12a, 12b and 1 for temperature control and temperature difference detection, respectively.
3a, 13b are provided, and each temperature control thermocouple 12a, 12b is provided with a temperature controller 14, respectively.
a, 14b, and each temperature difference detection thermocouple 13a, 13b is connected to an amplifier 15a, 15b of the temperature detection circuit 11, respectively.
Further, 16 is a first comparator that compares the outputs of both amplifiers 15a and 15b, and supplies the absolute value of the difference between the two to a temperature difference meter 17 and a second comparator 18 as a temperature difference. And in this second comparator 18,
The temperature difference between the upper and lower molds that does not interfere with the fitting, that is, the set value of the allowable temperature difference setting device 19 is input, and when the temperature difference exceeds the set value, an abnormality signal 21 is sent from the output section 20. is output, the abnormality display lamp 22 is lit, and the abnormality alarm buzzer 23 is activated, and on the other hand, a stop signal 24 of the device is outputted to stop the mold fitting operation.

That is, in this way, when a temperature difference occurs between the upper and lower mold blocks 1 and 2 and it becomes impossible to fit them, the abnormality signal 21 causes the indicator lamp 22 to light up and the alarm buzzer 23 to sound. to notify the worker of the abnormality and also send a stop signal 2.
4, the resin sealing device itself can be stopped, thereby preventing damage to the mold.

As detailed above, according to the present invention, the resin sealing device detects the heating temperature difference between the upper and lower mold blocks that are fitted to each other, and detects the temperature difference at which the temperature difference causes a problem in fitting. When this occurs, an abnormality signal is output to notify the operator of the abnormality, and a stop signal is output to stop the operation of the equipment.This will prevent the temperature control system from operating properly due to a malfunction or other reason. In this case, there is no risk of damaging the mold, and the device can operate effectively.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a conventional resin sealing device, FIG. 2 is an explanatory diagram of how the molds fit together, and FIG. 3 is a block diagram of a temperature difference detection circuit according to an embodiment of the present invention. FIG. 4 is a front view of the detector panel same as above. 1, 2... Upper and lower mold blocks, 3, 4... Upper and lower heat blocks, 5, 6... Upper and lower platens,
7... Type cylinder, 9... Transfer cylinder, 10... Guide post, 11... Temperature difference detection circuit, 13a, 13b... Temperature difference detection thermocouple,
16, 18... Comparator, 17... Temperature difference meter, 19
... Allowable temperature difference setting device, 20 ... Output section, 21 ...
...Abnormal signal, 24...Stop signal.

Claims (1)

[Claims] 1 Each is heated by a heat block,
It also has upper and lower mold blocks whose heating temperature can be controlled by a temperature control system, and a lead frame to be sealed is interposed between the two mold blocks, and these two mold blocks are mutually connected. In the apparatus which performs resin sealing by fitting into the upper and lower mold blocks, a means for detecting the temperature difference between the upper and lower mold blocks, a means for setting the allowable temperature difference, and the outputs of these two means are compared. 1. A resin sealing device for a semiconductor device, comprising means for outputting an abnormality signal and a device stop signal when a temperature difference exceeds a set value.