JPS6278835A - Resin sealing device for semiconductor element - Google Patents

Abstract

PURPOSE:To control the plunger speed arbitrarily with very high precision while facilitating its maintenance by a method wherein a plunger is driven by a motor to be speed-controlled correspondingly to the position thereof. CONSTITUTION:The turning force of a platten-driving motor 51 is converted into the thrust through the intermediary of a driving force conversion mechanism not shown in figure to lift a movable platten 4. Then an upper metallic mold 5 and a lower metallic mold 6 are brought into contact with each other to servo-lock the motor 51 for mold clamping at specified clamping pressure. In such a mold clamping state, a plunger 9 is driven by a plunger motor 10 such as an AC servomotor etc. to detect 11 the position of a plunger 9 for controlling the plunger speed i.e. the resin feeding speed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a resin sealing device for semiconductor devices for resin-sealing semiconductor devices onto a lead frame, and particularly relates to an improvement of the plunger drive portion thereof. be.

[Conventional technology]

In general, a resin sealing device for semiconductor devices includes an upper platen 1. As shown in FIG. A lower platen 2, a tie bar 3 provided between these two platens, and a movable platen 4 movably provided along the tie bar 3. The upper mold 5 is installed on the upper platen 1 and the lower mold 6 is installed on the movable platen 4, and the movable platen 4 is moved by hydraulic pressure to separate the upper mold 5 and the lower mold 6. Clamp the mold,
The lead frame and semiconductor element placed between the two molds are sealed with resin.

The structure of a conventional plunger portion in such a device is shown in FIG. In the figure, 7 is a tab left insertion hole into which a sealing resin 8 is inserted, and 9 is a plunger that is slidably arranged using the insertion hole 7 as a cylinder.This is a hydraulic plunger drive unit (not shown). driven,
The resin 8 is injected into the mold.

[Problem that the invention seeks to solve]

However, in such a conventional device, the plunger 9
Since the plunger is hydraulically driven, it is not possible to adjust the speed of the plunger, etc., and there is a problem that stable resin sealing cannot be achieved. In other words, in the conventional hydraulic drive system, the resin injection pressure is only managed by the driving hydraulic pressure of the plunger, and the resin injection speed (plunger speed) cannot be controlled. If it is too long, the wires connecting the board and the semiconductor element may be cut, or they may fall over and come into contact with adjacent wires, and air may be drawn into the resin, creating voids. There is a fear.

On the other hand, if it is slow, the injection will take time and there will be a problem that the manufacturing efficiency will be reduced.

Furthermore, the conventional hydraulic drive system has a problem in that maintenance is extremely complicated, such as detecting and preventing oil leakage, and replacing seals.

The present invention has been made in view of the above points, and aims to provide a resin sealing device for semiconductor elements that allows easy and highly accurate control of the speed of the plunger depending on its position and is easy to maintain. .

[Means for solving problems]

The resin sealing device for semiconductor elements according to the present invention includes a plunger motor that drives a plunger for injecting and pressing resin, a plunger position detection means for detecting the position of the plunger, and a speed of the plunger according to the detection result. A plunger speed control means is provided for controlling the plunger speed.

[Effect]

In this invention, the plunger is driven by a plunger motor such as an AC servo motor, the position of the plunger is detected, and the speed of the plunger, that is, the resin injection speed is controlled according to the detection result.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

Here, in the following explanation, a case of a single plunger will be explained as an example. FIG. 1 is a diagram showing a functional block of a plunger drive section in a resin sealing device for semiconductor elements according to an embodiment of the present invention.

This embodiment includes a plunger motor 10 that provides a driving force for driving the plunger 9, and a plunger position detection means 11 that detects the position of the plunger 9.
The plunger speed control means 12 receives the detection signal of the plunger position detection means 11 as input, and the plunger 9
Its moving speed depends on the position of the plunger motor 1.
The speed of 0 is controlled.

FIG. 2 shows an overall configuration diagram of a resin sealing device for semiconductor elements in which the plunger drive section described above is used. In this embodiment, the movable platen 4 is also driven by the platen driving motor 51, and is completely electric. That is, the movable platen 4 is moved by converting the rotation of the motor 51 into thrust by a driving force changing mechanism (not shown). Further, the plunger is provided in the lower mold 6, and the movable platen 4
It is designed to be driven via a plunger motor 10, a gear train 52, etc. attached to the engine.

FIG. 3 shows a specific configuration example for realizing the functional blocks of the plunger drive section shown in FIG. 1. In this embodiment, an AC servo motor is used as the plunger motor 10.
A potentiometer is used as the plunger position detection means 11. Further, 13 is a microcomputer, which inputs the output signal of the potentiometer 11 and drives the AC servo motor 51 for driving the moving platen.
This is for exchanging signals with external devices 15 such as the AC servo motor 10, controlling the rotational speed of the AC servo motor 10, and limiting the current (torque). Reference numeral 14 denotes a servo amplifier that receives commands from the microcomputer 13 and controls the drive of the AC servo motor 10. The microcomputer 13 and servo amplifier 14 control the plunger speed control means 12 shown in FIG. It is configured.

Further, 16 is a plunger drive mechanism for converting the rotational force of the AC servo motor IO into a thrust force for moving the plunger 9, and this is attached to the output shaft of the AC servo motor 10 as shown in FIG. Plunger drive shaft 16a and plunger 9 connected via gear train 52 etc.
It is comprised of a nut 16b fixed to, a ball screw 16C1 screwed into the nut 16b, and a pair of bevel gears 16d and 16e provided at one end of the plunger drive shaft 16a and the ball screw 16C, respectively.

Next, the operation will be explained.

First, the operation before the plunger operates, that is, until the mold is clamped, will be explained. When the start switch is turned on,
The platen drive motor 51 starts rotating, and the rotation is converted into thrust via a drive force conversion mechanism (not shown), thereby causing the movable platen 4 to rise. Then, when the upper mold 5 and the lower mold 6 come into contact and a certain tightening pressure is reached, the motor 51 is servo-locked and the molds are clamped.

Resin sealing is performed in this mold-clamped state, and the operation of the plunger in this case will be explained with reference to FIGS. 4 and 5. FIG. 4 is a flowchart showing a plunger operation control program stored in the memory of the microcomputer 13, and FIG. 5 is a diagram showing its driving pattern.

First, when the mold clamping is completed, the AC servo motor 10 for driving the plunger 9 starts rotating, and the rotational force is transmitted to the ball screw 16C via the bevel gear pair 16d, 16e. As the ball screw 16c rotates, the nut 16b, that is, the plunger 9, which is screwed into the ball screw 16c rises. Then, the microcomputer 13 activates the plunger 9
It is detected in step 20 that the resin has started to rise, and then in steps 21 to 26, the speed of the motor 10 is controlled to control the moving speed of the plunger 9 in three stages until the resin injection is completed. In other words, the motor speed until position PO is
When the plunger 9 is moved slowly at the motor speed V1 and it is detected that the plunger 9 has risen to the position PO, the plunger 9 is then moved to the position P1 at a faster motor speed V1, and it is detected that the plunger 9 has risen to the position P1. Then, in order to make the resin injection pressure the desired pressure, the current to the motor 10 is limited (
torque limit). At the same time, the motor speed is reduced to (2) and resin is slowly injected.

The resin is injected in this way, and when it is detected in step 27 that the positional fluctuation of the plunger 9 has become less than the specified value and that the resin injection has been completed, the pressurization time count starts from this point. Start (Step 2)
8). At the same time, the motor speed is decelerated to ultra-low speed v3 to maintain the injection pressure, and when the pressurization time amplifier is detected in this state, the motor current limit is turned off (step 29).
~31). Incidentally, at the time of the above-mentioned motor speed (3), the plunger 9 is actually stopped.

Next, in steps 32 to 35, the plunger 9 is separated from the resin, and in steps 36 to 41, the lead frame and semiconductor element sealed with the resin are taken out, that is, the resin is removed.

During steps 32 to 41, the plunger 9
is controlled to decrease by P2 at motor speed v4, increase by V5, and further increase by P3 at motor speed 6.

Then, in steps 42 to 48, the mold surface is cleaned, and in steps 49 and 50, the plunger 9
returns to the origin of the main drive pattern. During this time, the plunger 9 is controlled to once rise by P4 at a motor speed of 7, then descend to a position P5, and after completion of cleaning, further descend to the origin at a motor speed of 9.

In the device of this embodiment, the plunger 9 is driven and controlled by the AC servo motor 10 and the microcomputer 13, so there is no oil leakage, and a clean device that is easy to maintain and inspect can be realized. Furthermore, the position and speed of the plunger can be easily and precisely controlled, which was extremely difficult with conventional hydraulic drive systems, and resin sealing can always be performed with high quality and efficiency. That is, in this embodiment, the speed of the plunger 9 (motor speed) is controlled in three stages: low speed VO, high speed V1, and low speed V2 according to its position. Contact with adjacent wires due to falling wires and generation of voids can be prevented, and the overall time for resin injection can be shortened.

In addition, in the above embodiment, the speed of the motor during resin injection was controlled as V O - V 1 - V 2, but the method of controlling the motor speed is not limited to this.
It may be set appropriately depending on the various conditions such as the resin and the mold.

〔Effect of the invention〕

As described above, according to the resin sealing device for semiconductor elements according to the present invention, the plunger is driven by a motor and its speed is controlled according to the position of the plunger, so maintenance is facilitated. In addition, the speed of the plunger can be adjusted arbitrarily and with very high precision to achieve efficient and high-quality resin sealing.

[Brief explanation of drawings]

FIG. 1 is a functional block diagram of a plunger drive section of a resin sealing device for semiconductor devices according to an embodiment of the present invention, FIG. 2 is an overall configuration diagram of the device, and FIG. 3 is a function diagram of the functions shown in FIG. 1 above. FIG. 4 is a flow chart for explaining the operation of the plunger of the device; FIG. 5 is a diagram showing the drive pattern of the plunger of the device; FIG. 7 is a configuration diagram of a conventional resin sealing device for semiconductor elements, and FIG. 7 is an enlarged view showing the plunger portion thereof. 5... Upper mold, 6... Lower mold, 9... Plunger, 10... AC servo motor, 11... Potentiometer, (plunger position detection means), 12... Plunger speed control Means, 13... microcomputer, 14... servo amplifier. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] (1) In a semiconductor device resin sealing device for resin-sealing a semiconductor device onto a lead frame, a plunger is provided in the upper mold or the lower mold to inject and press the resin, and the plunger is driven. A plunger motor that provides a driving force for the plunger, plunger position detection means for detecting the position of the plunger, and plunger speed control means for controlling the moving speed of the plunger according to the position detection result. Resin sealing equipment for semiconductor devices.