JPH06198689A - Mold apparatus - Google Patents

Abstract

PURPOSE:To prevent the occurrence of pressure abnormality even in the high velocity injection and enable rational injection to be effected by pouring resin in a state of velocity control to a set position in use of a plunger driven by an electric motor, and thereafter pouring resin in a state of pressure control, and subsequently stopping resin pouring for a certain period as exceeding an allowable pressure and resuming resin pouring after the lowering of pressure. CONSTITUTION:The resin pouring pressure is detected by detecting means 17. After the plunger is controlled by velocity control means 18 to be the set speed pattern, the detected resin pressure is fed back and the plunger position is controlled by pressure control means 19 to be the set pressure. The switching Is carried out by control method switching means 21 as velocity/pressure control method switching position detecting means 20 detects the plunger. When pressure abnormality detecting means 22 detects that the resin pressure under pouring exceeds the set value of pressure abnormality through velocity control, the signals are inputted by the velocity control means 18 so as to stop the plunger for a certain period, and as the resin is melted and no pressure abnormality signals are inputted, the velocity control is resumed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding apparatus used for resin molding of semiconductors, for example.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 3, as a molding apparatus used for resin molding of semiconductors, an upper platen 1, a lower platen 2, a tie bar 3 provided between these platens, and a tie bar 3 are provided. A movable platen 4 and a drive unit for the movable platen 4 are provided so as to be movable along. Then, the upper die 5 is installed on the upper platen 1, the lower die 6 is installed on the moving platen 4, and the moving platen 4 is moved by hydraulic pressure to clamp the upper die 5 and the lower die 6,
The lead frame and the semiconductor element placed between the two molds are resin-sealed.

FIG. 4 shows the structure of a conventional plunger portion in such a device. In the figure, 7 is a tablet insertion hole into which a sealing resin (tablet) 8 is inserted, and 9 is a plunger that is slidably arranged with the insertion hole 7 as a cylinder. This is a hydraulic plunger not shown. It is driven by a drive unit to inject the resin 8 into the mold.

The above is a conventional example of a plunger-driving type molding apparatus driven by hydraulic pressure. Recently, a method of driving the plunger by a servomotor has been adopted. The plunger drive unit in that case is shown in FIG. 5, and the control structure is shown in FIG. 5, a servomotor 10 rotates a ball screw 12 connected to its output shaft by a timing belt 11, and a ball screw nut 13 penetrating the ball screw 12 moves up and down. This ball screw nut 1
The above-mentioned plunger 9 is fixed to 3 via a pressure detector 14 of the load cell, and the resin 8 is injected into the mold. In such a structure, in the control configuration shown in FIG. 6, a plunger driving means 15 including a servo motor for driving a plunger and a driver thereof, a plunger position corresponding to an encoder for detecting the rotation amount of the servo motor and detecting the position of the plunger. Detection means 16,
Resin pressure means 17 corresponding to a plunger, that is, a load cell for detecting the pressure applied to the resin, is connected to each of the control devices.

In the control device, a speed control means 18 for controlling the plunger 9 to have a preset speed pattern,
The pressure control means 19 for controlling the plunger so as to maintain the pressure applied to the resin at a preset pressure by feeding back the output of the resin pressure detection means 17, the plunger position detection means 1
The V / P switching position detecting means 20 detects the plunger position at which the output of 6 is input to switch from the preset speed control to the pressure control, and the control method switching means 2 receives it.
1 switches the control means. Incidentally, when the pressure value detected by the resin pressure means 17 exceeds the preset abnormal pressure value during the injection process, the injection is immediately stopped and the apparatus is brought to an emergency stop.

[0006]

In recent years, in the resin molding of semiconductors, a rapid curing resin has been used for the purpose of improving productivity. In such a quick-curing resin,
It is necessary to inject the resin into the mold within a short time before the resin starts to cure. However, in the injection process, high pressure is applied to the tip of the plunger because the resin is not sufficiently melted at the beginning of the injection. In the case of the plunger drive system of the hydraulic drive system in the above-mentioned prior art, if high pressure is applied to the tip of the plunger when the resin is not sufficiently melted,
Since it is hydraulically driven, the plunger speed becomes slower, and no pressure higher than a predetermined cure pressure is applied. Instead, the plunger speed becomes slower, and the resin begins to harden during the injection, resulting in unfilled defects.

On the other hand, in the case of the servo drive plunger drive system in the above-mentioned prior art, even if the pressure at the tip of the plunger is high in the speed control range, the resin is forcibly injected with priority to the speed. The resin does not harden during the injection. However, if the pressure at that time becomes too high, product defects such as resin leakage, burrs, and wire flow will occur. If the injection speed is slowed down so that such a high pressure is not generated, an unfilled defect occurs as in the hydraulic drive system. Normally, the speed of the plunger is set as high as possible without causing such high pressure.

FIG. 7 shows changes in the pressure applied to the injected resin in the case of the plunger drive system by servo drive. However, if there is a preheated state of the resin or there is a variation in the amount of resin, the resin pressure may exceed the preset abnormal pressure value.
In such a case, the device will be immediately shut down and the injection stopped. Once the injection is stopped, the resin cannot be restored until the resin inside the mold is completely cured. In this case, since no pressure was applied to the resin, the curing time of the resin was about 5 times longer than usual, and it took longer to restore the resin, which hindered improvement in production efficiency.

The present invention has been made in view of the above circumstances, and an object thereof is to set an injection speed limit without paying too much attention to variations in resin conditions in high-speed resin injection by a servo drive plunger drive system. It is an object of the present invention to provide a molding apparatus having a resin injection control method capable of preventing defects such as voids and unfilling, and improving productivity and yield without stopping the apparatus due to abnormal pressure.

[0010]

[Means for Solving the Problems]

1. Positioning means for detecting the plunger driving means and the position of the plunger by the electric motor, speed control means for controlling the speed of the plunger to a preset speed pattern, pressure detecting means for detecting the pressure applied to the injected resin, and feedback of the detected pressure Pressure control means for controlling the position of the plunger so that the pressure applied to the injected resin becomes a preset holding pressure, and a pressure abnormality for detecting that the pressure detected by the pressure detecting means exceeds a preset abnormal pressure. Detection means,
It comprises a "speed / pressure" control method switching position detecting means for detecting the position of the plunger for switching the preset speed control to the pressure control, and a control switching means for switching the speed control to the pressure control.

2. The plunger driving means by the electric motor and the position detecting means for detecting the plunger position, the speed detecting means for detecting the speed of the plunger, the speed controlling means for controlling the speed of the plunger to a preset speed pattern, and the pressure applied to the injected resin are Pressure control means for controlling the position of the plunger so that the pressure applied to the injected resin by feeding back the detection means and the detected pressure to the preset holding pressure,
Pressure abnormality detection means for detecting that the pressure detected by the pressure detection means exceeds a preset abnormal pressure, and "speed / pressure" control for detecting the position of the plunger for switching from the preset speed control to the pressure control. A method switching position detecting means, and a "pressure / speed" control method switching speed detecting means for comparing the current speed detected by the speed detecting means with the set speed for speed control and detecting that the current plunger speed exceeds the set speed. , Control switching means for switching from the speed control to the pressure control.

[0012]

[Action]

1. The speed is controlled by the speed control means so that the speed of the plunger has a preset speed pattern by the resin injection by the plunger driving means by the electric motor. The pressure detecting means detects the pressure applied to the injected resin. The speed control is also up to the preset position, after that the pressure applied to the injected resin is detected by the pressure detection means, and the pressure is fed back to adjust the pressure applied to the injected resin to the preset holding pressure. Is controlled by the pressure control means. The plunger position detecting means detects the position of the plunger, and when the "speed / pressure" control method switching position detecting means detects the position of the plunger for switching the control means from the preset speed control to the pressure control, Switching means switches the control means from speed control to pressure control.

When the pressure abnormality detecting means detects that the pressure detected by the pressure detecting means exceeds the preset abnormal pressure value together with the "speed / pressure" control method switching position detecting means,
The operation of the plunger is stopped and held at that position for a certain period of time.
If the pressure detected by the pressure detecting means has dropped to the preset holding pressure after a certain period of time, the injection by speed control is restarted again. If the pressure has dropped, stop and hold again for a fixed time. If this is repeated several times, the injection is stopped and the device is stopped in the conventional manner.

2. The speed is controlled by the speed control means so that the speed of the plunger has a preset speed pattern by the resin injection by the plunger driving means by the electric motor. The pressure detecting means detects the pressure applied to the injected resin. The speed control is also up to the preset position, after that, the pressure applied to the injected resin is detected by the pressure detection means, and the pressure is fed back to adjust the pressure applied to the injected resin to the preset holding pressure. The position is controlled by the pressure control means.

The plunger position detecting means detects the position of the plunger, and when the "speed / pressure" control method switching position detecting means detects the position of the plunger for switching the control means from the preset speed control to the pressure control, The switching means of the control means switches the control means from speed control to pressure control. "Velocity / pressure" control method switching When the position is detected and the pressure abnormality detection means detects that the pressure detected by the pressure detection means exceeds the preset abnormal pressure value, the control switching means controls from speed control to pressure control. Switch means.

However, in that case, the pressure control means controls the pressure applied to the injected resin so as to be a preset abnormal pressure value. At that time, the plunger speed detection means constantly monitors the speed of the plunger, and the "pressure / speed" control method switching speed detection means detects that the speed of the plunger exceeds the speed of the preset speed pattern, and then switches the control. The means switches the control means from pressure control to speed control.

[0017]

EXAMPLES Examples of the present description will be described below with reference to FIGS.
The description will be made with reference to FIGS. 4 and 5.

First, FIG. 5 shows the structure of a semiconductor molding apparatus, in which 1 is an upper platen and 2 is a lower platen.
A diver 3 provided between these platens, and a movable platen 4 movably provided along the diver 3.
And its drive unit. Then, the upper mold 5 is installed on the upper platen 1, the lower mold 6 is installed on the moving platen 4, and the moving platen 4 is moved by a driving unit composed of a servo motor to move the upper mold 5 and the lower mold 6 together. The mold is clamped, and the lead frame and the semiconductor element mounted between the two molds are resin-sealed.

A servomotor 10 rotates a ball screw 12 connected to the output shaft of the servomotor by a timing belt 11, and a ball screw nut 13 which is inserted into the ball screw nut 12 and fixed to the ball screw nut 13 moves up and down. The above-mentioned plunger 9 is fixed to the ball screw nut 13 via a pressure detector 14 of the load cell. In addition, in FIG.
Reference numeral 7 denotes a tablet insertion hole into which a sealing resin (tablet) 8 is inserted, and the plunger 9 is slidably arranged with the insertion hole 7 as a cylinder. It is what is injected into the mold.

In the semiconductor mold device having the above structure, the construction of the embodiment of claim 1 will be described. First, FIG. 1 shows a control configuration for controlling the plunger 9. In the figure, the plunger driving means 15 is the servo motor 1 described above.
0 and its drive circuit, the encoder attached to the shaft on the anti-load side of the servomotor 10 and the pulse counter configured in the control device of the device correspond to the plunger position detecting means 16, and the detection signal thereof is software. Is input to the V / P switching position detecting means 20. The resin pressure detecting means 17 corresponds to the load cell 14, and the detection signal thereof is A / D converted and input into the control device, and is input to the software pressure abnormality detecting means 22 as well as the software pressure controlling means 19.

The output of the V / P switching position detecting means 20 is
It is input to the control method switching means 21. The output of the pressure control means 19 and the speed control means 18 by software is input to the control method switching means 21, and either input is selected and output to the plunger drive means 15. The output of the pressure abnormality detection means 22 is input to the speed control means 18, and the speed control means 18 controls so that the plunger is stopped and held when receiving the input from the pressure abnormality detection means 22.

Further, in the same semiconductor mold device, the configuration of the embodiment of claim 2 will be described. First, FIG. 2 shows a control configuration for controlling the plunger 9. In the figure, a plunger drive means 15 corresponds to the servo motor 10 and its drive circuit, and an encoder attached to the shaft on the side opposite to the load of the servo motor 10 and a pulse counter configured in the controller of the device detect the plunger position. Means 16 and the detection signal is V by software
It is input to the / P switching position detecting means 20 and the plunger speed detecting means 23. The plunger speed detecting means 23 obtains the speed of the plunger by differentiating the plunger position, and the processing result is the P / V switching speed detecting means 24.
Is output to.

The resin pressure detecting means 17 is the load cell 1 described above.
4, the detection signal is A / D converted and input into the control device, and is input to the software pressure control means 19 as well as the software pressure abnormality detection means 22. The outputs of the V / P switching position detecting means 20, the pressure abnormality detecting means 22, and the P / V switching speed detecting means 24 are input to the control method switching means 21. The output of the pressure control means 19 and the speed control means 18 by software is input to the control method switching means 21, and either input is selected and output to the plunger drive means 15.

In the above semiconductor mold device, FIG.
And each means of FIG. 2 acts as follows. Further, FIG. 8 shows a graph showing the pressure change when the resin pressure is controlled by the control method of this embodiment.

The speed control means 18 controls the speed of the plunger to be a preset speed pattern. The speed control is also up to the preset position, and thereafter, the pressure applied to the injected resin is detected by the load cell 14, and the pressure is fed back to adjust the position of the plunger so that the pressure applied to the injected resin becomes the preset holding pressure. It is controlled by the pressure control means 19. An encoder attached to the anti-load side shaft of the servomotor 10 and a pulse counter configured in the control device of the device detect the position of the plunger, and the "speed / pressure" control method switching position detection means 20 sets in advance. When the position of the plunger for switching the control means from the speed control to the pressure control is detected, the control means switching means 2
1 switches the control means from speed control to pressure control. The above is the normal injection operation.

In the embodiment of claim 1, when the control means 18 controls the speed of the plunger to have a preset speed pattern, the injected resin pressure detected by the resin pressure detection means 17 becomes high, When the abnormality detection means 22 detects that the preset pressure abnormality value is exceeded, the detection signal is output to the speed control means 18. Speed control means 1
When the pressure abnormality detection signal is received, the speed controller 8 interrupts the speed control during operation and controls the plunger to stop and hold.
The plunger is held in a stopped state for 2 seconds to melt the resin, and when the abnormal pressure detection signal is no longer input, the original speed control is restored and normal injection is performed.
If a pressure abnormality detection signal is input even after 2 seconds have elapsed, the injection is stopped as usual and the apparatus is brought to an emergency stop.

According to the second aspect of the present invention, the speed control means 18 is arranged so that the speed of the plunger has a preset speed pattern.
When the pressure abnormality detection unit 22 detects that the pressure of the injected resin detected by the resin pressure unit 17 has increased and the pressure abnormality detection unit 22 has exceeded the preset pressure abnormality value, the pressure abnormality detection unit 22 outputs the pressure abnormality signal. In response to this, the control means switching means 21 switches the control means from speed control to pressure control.

However, in this case, the pressure control means 19 controls so that the pressure applied to the press-fitted resin becomes a preset abnormal pressure value. Plunger speed detecting means 23
Always detects the speed of the plunger, and when the P / V switching speed detecting means 24 detects that the speed of the plunger exceeds the speed of the preset speed pattern, the detection signal is output to the control means switching means 21. To do. Control means switching means 2
When No. 1 receives the detection signal, it switches the control method from pressure control to speed control, restores the original speed control, and performs injection as usual.

According to this embodiment, both the embodiments of the claims can prevent the occurrence of the pressure abnormality even under the high-speed injection condition where the pressure abnormality is likely to occur, so that the production efficiency of the apparatus can be improved. You can Even if the injection is performed under the high-speed injection condition, the pressure does not become abnormal even if the resin is preheated or the resin amount varies. Therefore, ideal injection is possible and high quality products can be produced with high yield.

[0030]

According to the present invention, as is clear from the above description, there is a preheated state of the resin, a variation in the amount of the resin, and the like with respect to the pressure abnormality which is a phenomenon peculiar to the servo drive injection type semiconductor mold device. However, since the ideal injection can always be performed, it has an excellent effect that a good quality product can be produced with a high yield.

[Brief description of drawings]

FIG. 1 is a control configuration diagram according to an embodiment of the present invention,

FIG. 2 is a control configuration diagram according to an embodiment of the present invention,

FIG. 3 is a front view of a conventional semiconductor molding device,

FIG. 4 is a detailed view of the tip of the plunger,

FIG. 5 is an overall view of a servo drive type semiconductor molding device.

FIG. 6 is a conventional control configuration diagram of a servo drive type semiconductor mold device;

FIG. 7 is a pressure change diagram of a conventional control method for a servo drive type semiconductor mold device;

FIG. 8 is a pressure change diagram when the resin pressure is controlled by the control method according to the present invention.

[Explanation of symbols]

14 is a pressure detector, 15 is a plunger drive means, 16 is a plunger position detection means, 17 is a resin pressure detection means, 18 is a speed control means,
Reference numeral 19 is pressure control means, 20 is V / P switching position detection means, 21 is control method switching means, 22 is pressure abnormality detection means, 23 is plunger speed detection means, 24
Is a P / V switching speed detecting means.

Claims (2)

[Claims] 1. A plunger driving means using an electric motor and a position detecting means for detecting the position of the plunger, a speed controlling means for controlling the speed of the plunger to a preset speed pattern, and a pressure detecting means for detecting the pressure applied to the injected resin. And the pressure control means for feeding back the detected pressure to control the position of the plunger so that the pressure applied to the injected resin becomes the preset holding pressure, and the pressure detected by the pressure detecting means exceeds the preset abnormal pressure. A pressure abnormality detection means for detecting that the speed control is switched from the preset speed control to the pressure control, and a "speed / pressure" control method switching position detection means for detecting the position of the plunger, and the speed control is switched to the pressure control. A molding apparatus comprising a control switching means and performing resin injection control. 2. A plunger driving means using an electric motor, a position detecting means for detecting the position of the plunger, a speed detecting means for detecting the speed of the plunger, and a speed control means for controlling the speed of the plunger to a preset speed pattern. Pressure detection means for detecting the pressure applied to the injected resin and pressure control means for feeding back the detected pressure to control the position of the plunger so that the pressure applied to the injected resin becomes a preset holding pressure, and detection by the pressure detection means Pressure abnormality detection means for detecting that the pressure exceeds a preset abnormal pressure, and "speed / pressure" control method switching position for detecting the position of the plunger for switching the control means from the preset speed control to the pressure control The current speed detected by the detection means and the speed detection means are compared with the set speed for speed control, and the current plunger speed exceeds the set speed. A molding apparatus comprising: a "pressure / speed" control method switching speed detecting means for detecting the occurrence of a failure, and a control switching means for switching from the speed control to the pressure control, for resin injection control.