JPH0422975Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention relates to the improvement of a transfer resin sealing device for sealing and molding a semiconductor element with a resin material, in particular, a plunger for pressurizing a resin material. The present invention relates to an improvement in the reciprocating sliding mechanism of.

(Prior Art) A transfer resin sealing apparatus has been conventionally used as an apparatus for sealing and molding a semiconductor element with a resin material.

This conventional device usually consists of a fixed upper mold, a movable lower mold disposed opposite to the upper mold, and a vertical reciprocating sliding mechanism (mold (clamping/mold opening mechanism), a pot for supplying resin material placed on either the upper or lower mold, a plunger to pressurize the resin material fitted into the pot, and upper and lower parts of the plunger that slide the plunger up and down and back and forth. It consists of a reciprocating sliding mechanism, a large number of cavities arranged opposite to the PL (parting line) surfaces of both types, and a passage for transferring molten resin material that communicates the cavities with the pot.

Transfer resin encapsulation molding of a semiconductor element using this apparatus involves heating the resin material supplied in the pot to a predetermined temperature and applying pressure to a predetermined pressure using a plunger to melt it, and By injecting the molten resin material into the cavities of both types through the transfer passage using pressure, the semiconductor element on the lead frame fitted and set in the cavity is sealed with resin. .

In addition, the plunger for pressurizing the resin material is reciprocated in the vertical direction when supplying the resin material into the pot and when pressurizing the supplied resin material, but this vertical reciprocating sliding mechanism uses hydraulic pressure. Hydraulic mechanisms using

In addition, it has been proposed to use an electric worm jack for the vertical reciprocating sliding mechanism of the plunger, an electric crank for the vertical reciprocating mechanism of the lower mold, and a hydraulic jack for mold clamping during resin molding (for example, in practice). Publication number 61-148610).

(Problems to be solved by the invention) By the way, when a hydraulic mechanism is adopted as the up and down reciprocating sliding mechanism of the plunger in a transfer resin sealing device for semiconductor devices, the following problems occur in actual resin sealing molding work. There is a problem like this.

In other words, this type of equipment is strongly required to have high quality or high reliability of the molded resin-sealed molded product, and is also required to have high efficiency and productivity. In order to achieve this, it is necessary not only to satisfy the general molding conditions for resin molding, but also to ensure that the injection pressure and injection speed of the resin material into the cavity are predetermined or stable; It is also necessary to satisfy resin molding conditions such as being able to adjust injection pressure and injection speed relatively easily and reliably.

However, in the plunger reciprocating sliding mechanism using the hydraulic mechanism, the viscosity of the oil fluctuates due to changes in oil temperature during the operation of the mechanism, so during resin encapsulation molding, It becomes extremely difficult to obtain the above-mentioned predetermined or stable injection pressure and injection rate. Therefore, because resin encapsulation molding conditions are not always constant, there are serious problems such as not being able to fully achieve the intended purpose of high quality or high reliability of this type of molded product and its high efficiency productivity. There are problems with resin molding.

The present invention reliably solves the above-mentioned conventional problems with hydraulic mechanisms by adopting a plunger reciprocating sliding mechanism consisting of a screw jack mechanism instead of a plunger reciprocating sliding mechanism consisting of a hydraulic mechanism. The purpose is to

In addition, the present invention employs a vertical reciprocating sliding mechanism of the plunger consisting of an electric screw shaft mechanism, and a pressing force applied to the resin material between the screw shaft and the plunger holder in the vertical reciprocating sliding mechanism of the plunger. By installing a detection load meter and automatically controlling the vertical and reciprocating sliding of the screw shaft based on the pressure detection signal from the load meter, the injection of molten resin material into the mold cavity is controlled at a predetermined level. Or at a stable injection pressure and injection rate, thereby
It is an object of the present invention to improve the quality or reliability of semiconductor resin-sealed molded products and their productivity, and to provide a resin-sealing device for semiconductor elements that has excellent usability and operability.

(Means for Solving the Problems) A resin encapsulation device for a semiconductor element according to the present invention includes an upper mold, a lower mold disposed opposite to the upper mold, and a plurality of pots disposed on the lower mold. , a plunger for pressurizing a resin material fitted into the pot, a plunger holder in which each of the plungers is freely fitted and supported, and a plunger for vertically reciprocatingly sliding each of the plungers through the plunger holder. A resin sealing device for a semiconductor element is provided with a vertical reciprocating sliding mechanism of the plunger, wherein the vertical reciprocating sliding mechanism of the plunger is constituted by an electric screw jack mechanism using a servo motor as a driving source, and the electric screw A load meter for detecting the pressing force on the resin material is installed between the screw shaft and the plunger holder in the screw mechanism, and based on the detection signal from the load meter, the torque of the servo motor is controlled and forward/reverse rotation switching is performed. It is characterized by being configured so that operations are performed automatically.

(Function) According to the present invention, the plunger can be reciprocated up and down by the electric screw jack mechanism.

In addition, a load meter installed between the screw shaft and the plunger holder in the vertical reciprocating sliding mechanism of the plunger detects the pressure applied to the resin material in the pot, and the pressure applied to the plastic material in the pot is detected based on the pressure detection signal. By automatically controlling the vertical and reciprocating sliding of the U-shaft, the molten resin material can be injected into the cavity at a predetermined or stable injection pressure and injection speed.

(Example) Next, the present invention will be explained based on embodiment figures.

The figure shows the main parts of a transfer resin sealing device for a semiconductor element according to the present invention.

This device includes a fixed upper mold 1, a movable lower mold 2 disposed opposite to the upper mold 1, a plurality of pots 3 disposed on the lower mold 2, and a resin material fitted into the pots 3. A plunger 4 for pressurization, and both upper and lower molds 1 and 2
a resin molding cavity 5 installed opposite to the PL surface of the
A passage 6 for transferring molten resin material that communicates the cavity 5 and the pot 3, and a plunger in which the proximal end (lower end) ₄₁ of the plunger 4 is freely (loosely fitted) fitted and supported. It consists of a holder 7 and a reciprocating mechanism 8 for vertically reciprocating the plungers 4, which reciprocally slides each of the plungers 4 up and down through the plunger holder 7.

In addition, the lower mold 2 side described above is operated by an appropriate vertical drive mechanism, that is, a mold clamping/mold opening mechanism (not shown).
It is provided so as to slide vertically and reciprocally with respect to the fixed upper mold 1. Furthermore, the vertical reciprocating sliding mechanism 8 of the plunger 4 described above is integrally installed on the lower mold 2 side. It is also provided so that it can be slid back and forth up and down as it moves.

Further, the upper end portion ₄₂ of the resin material pressurizing plunger 4 is fitted into the pot 3 in a normal state. Further, as described above, the base end 4 ₁ is freely fitted and supported by the plunger holder 7, and the base end 4 ₁ is provided with an elastic pressing member provided in the plunger holder 7. The elasticity of a spring 9 (in the illustrated example, a compression spring) is applied through a seat 10.

Note that the seat 10 described above is in contact with the upper stopper surface in the plunger holder 7 in the normal state (when the mold is opened), and therefore, at this time, the elasticity of the elastic pressing member 9 is the same as that of the plunger for pressing the resin material. It is not directly added to 4. However, after mold clamping, when the holder 7 moves upward and the plunger 4 begins to pressurize the resin material in the pot 3, the plunger 4 becomes relatively downwardly moved. 4 is provided so that the elasticity of an elastic pressing member 9 is directly applied to the plunger 4 via a seat 10 as a force to move the plunger 4 upward.

Further, the vertical reciprocating sliding mechanism 8 of the plunger 4 described above is composed of an electric ball screw mechanism.

That is, as described above, this vertical reciprocating sliding mechanism 8 is integrally installed at the lower part of the movable lower die 2 side via the fixed frame 11.

Further, the vertical reciprocating sliding mechanism 8 is engaged with a servo motor 12 and a horizontal rotating shaft 13 that is driven and rotated by the servo motor 12 in both forward and reverse directions, and is engaged perpendicularly to the horizontal rotating shaft 13 side and is horizontal. Rotating shaft 13
a vertically rotating nut member 14 that is shaft-mounted to rotate in both forward and reverse directions as the nut rotates in both forward and reverse directions;
A screw shaft 15 screwed onto the rotating nut member 14, a large number of rotating balls fitted into engagement screw grooves between the screw shaft 15 and the nut member 14, and the screw shaft 15. It consists of a rotation means (not shown), etc. for the rotation. Therefore, the screw shaft 15
is provided to move vertically by rotating the servo motor 12 in forward and reverse directions.

Further, an engagement connecting member 16 is attached to the upper part of the screw shaft 15 for detachably engaging and connecting it to the bottom side of the plunger holder 7 described above.

In addition, in the above embodiment, the mold opening process for both molds, the lead frame process, the mold clamping process for both molds, the resin sealing molding process for semiconductor elements, the mold opening process for both molds,
This figure is equipped with an automatic control mechanism for the servo motor 12 for the purpose of adapting to automatic and continuous normal resin molding cycles such as the product take-out process.

That is, this automatic control mechanism uses the servo motor 12
The screw shaft 15 (and plunger 4) is moved upward by rotating in the forward direction to pressurize the resin material into the pot 3 (transfer action to the cavity 5 side), and then the next resin is For the molding process, the servo motor 1 moves the screw shaft 15 downward by rotating the servo motor 12 in the opposite direction.
2, the switching operation between forward and reverse rotation directions is automatically performed.

In addition, in order to detect the plunger pressing force against the resin material in the pot 3, a required load meter 17 is installed between the upper end surface of the screw shaft 15 and the lower end surface of the engagement connecting member 16. ,
Pressure detection signal 17 detected by the load cell 17
₁ is input into an automatic control circuit 18, and the control signal ₁₈₁ outputted from the automatic control circuit 18 is configured to automatically control the torque of the servo motor 12 and switch between forward and reverse rotation directions. It is something.

Further, the rotation speed of the servo motor 12 is automatically controlled based on a detection signal from a detection sensor such as a rotary encoder attached to the servo motor 12 (not shown).

Further, when the load meter 17 described above detects a predetermined pressing force of the resin material by the plunger 4 and inputs the detection signal 17 ₁ to the automatic control circuit 18, the screw shaft 15 is
It is constructed so that it can be locked (preventing vertical sliding of the shaft 15) via a mechanical or electrical locking mechanism. Therefore, when a predetermined pressing force on the resin material is detected, substantially simultaneously with this detection, the forward rotation of the servo motor 12 is immediately stopped, and the vertical sliding of the screw shaft 15 is prevented. .

In addition, the symbols 19 and 20 in the figure are the cavity 5.
The figure shows an ejector mechanism for ejecting a semiconductor resin-sealed molded article (product) between the upper and lower molds 1 and 2, and when the mold is clamped as shown in the figure, the ejector pins 19 ₁ , At the time of mold opening, in which the respective tip surfaces of 20 ₁ are retreated to the outside (bottom surface) of both mold cavities 5 and the lower mold 2 is moved downward, those ejector pins 19 ₁ ,
20 ₁ is provided so that the semiconductor resin-sealed molded product can be projected between the molds 1 and 2 by advancing each end face of the mold cavity 5 into the mold cavity 5 .

Resin encapsulation of a semiconductor element in the transfer resin encapsulation apparatus of the above embodiment is carried out as follows.

In advance, the lower mold 2 is moved downward to open both the upper and lower molds 1 and 2, and the plunger 4 is also moved downward.

Next, a lead frame (not shown) on which a semiconductor element is mounted is set at a predetermined position on the upper surface of the lower mold 2.

Next, a resin material is supplied into the pot 3 of the lower mold 2, and the lower mold 2 is moved upward to clamp both the upper and lower molds. Note that during this mold clamping, the semiconductor elements on the lead frames described above are fitted into the cavities 5 of both molds.

Next, when the servo motor 12 is rotated forward to move the screw shaft 15 upward, the load cell 1 integrally attached to the upper part of the shaft 15 is moved upward.
7. Engagement connection member 16. Plunger holder 7
and the resin material pressurizing plunger 4 move upward at the same time. When the screw shaft 15 moves upward, the upper end ₄₂ of the plunger 4 pressurizes the resin material, but when this pressure exceeds a certain level, the plunger 4 moves relative to the upward movement of the plunger holder 7. try to move downward. However, at this time, upward elasticity is applied to the plunger 4 by the aforementioned elastic pressing member 9 via the seat 10, so that the resin material receives a predetermined pressing force due to the elasticity.

At this time, since the servo motor 12 is under torque control based on the pressure detection signal ₁₇₁ from the load cell 17, the resin material is eventually subjected to a predetermined application by the plunger 4. It is something that can apply pressure.

Further, since the above-mentioned resin material is heated to a predetermined temperature by a heater (not shown) in the pot 3, the resin material is melted by this heating, and the molten resin material is heated by the pressing force of the plunger 4. The two mold cavities 5 are injected and filled through the transfer passage 6. Therefore, the semiconductor element fitted into the cavity is sealed and molded with the injected resin material.

After the resin encapsulation molding described above, the lower die 2 is moved down to its original position again and both the upper and lower dies 1 and 2 are opened, thereby forming the resin encapsulation molded body (product) of the semiconductor element and the lead frame. The ejector pins 19 ₁ , 20 ₁ of the upper and lower ejector mechanisms 19 , 20 are ejected to the outside of both cavities 5 .

In addition, in order to move the screw shaft 15 down to its original position prior to the step of supplying the resin material into the pot 3 in the next resin sealing molding,
The servo motor 12 may be rotated in the opposite direction. However, this servo motor 12
The reverse rotation operation is performed using the screw shaft 1 described above.
The automatic control of the vertical reciprocating sliding mechanism 8 can be carried out after the pressurizing action on the resin material in the pot 3 based on the upward movement of the pot 5 and the normal pressure holding action necessary for resin molding are completed. , are performed automatically and continuously in connection with each of the above-mentioned actions.

That is, the automatic control of the vertical reciprocating sliding mechanism 8 described above is performed by inputting the pressure detection signal 17 ₁ detected by the load meter 17 to the automatic control circuit 18 when the plunger 4 pressurizes the resin material, and
By outputting the control signal ₁₈₁ from the automatic control circuit 18, the rotational torque of the servo motor 12 can be controlled or its rotation can be temporarily stopped, thereby preventing excessive pressurization and pressure holding action. .

Therefore, after the time required for pressurizing and holding the resin material described above has elapsed, the servo motor 1
2 and lowering the screw shaft 15 to a predetermined position are automatically and continuously carried out, the mold opening process for both molds, the lead frame setting process, and the process for both molds are completed. Mold clamping process, resin sealing molding process for semiconductor elements, mold opening process for both molds,
The resin molding cycle, including the product removal process, can be automatically and continuously adapted.

In addition, the injection pressure and injection speed of the resin material into the cavity by automatic control of the above-mentioned vertical reciprocating sliding mechanism 8 become predetermined or stable,
Furthermore, the injection pressure and injection rate can be adjusted relatively easily and reliably.

That is, in resin encapsulation molding of semiconductor elements,
Usually, a thermosetting resin material such as an epoxy resin is used, and due to its nature, the heated and melted resin material begins to harden over time. Therefore, the time for injecting the molten resin material into the cavity is usually set within the range of approximately 20 to 30 seconds, which is approximately the same as the gelation time. In addition, the gelation time described above tends to be shortened as much as possible for the purpose of high efficiency productivity, and the gelation and curing time of the resin material described above is determined by the heating temperature of the resin material (the mold temperature). Preset temperature)
Because it is greatly influenced by
In actual resin molding work, it is preferable to be able to respond appropriately and quickly to various resin molding conditions.

According to the configuration of the above embodiment, the injection pressure and injection speed of the molten resin material can be arbitrarily set to suit the various resin molding conditions described above,
Furthermore, since it is possible to set the injection speed of the resin material in a desired manner within the range of the resin injection time described above, for example, the injection speed can be set in a multi-stage speed range such as five stages. Therefore, it is possible to appropriately and quickly respond to the various resin molding conditions described above.

(Effects of the invention) According to the configuration of the invention, compared to conventional devices that use a hydraulic mechanism for the vertical and reciprocating sliding mechanism of the plunger, the resin material can be injected into the mold cavity in a predetermined or stable manner. This effect can be achieved by adjusting the injection pressure and injection rate.

In addition, since the injection pressure and injection speed described above can be easily and reliably adjusted, the objectives of high quality or high reliability of resin-sealed molded products and high efficiency productivity can be fully achieved. In addition, the present invention has extremely practical effects in that it is possible to provide a resin sealing device for semiconductor elements that is excellent in usability and operability.

Furthermore, conventional devices using hydraulic mechanisms have increased in overall weight and shape due to the attachment of hydraulic tanks, hydraulic pipes, and other accessories, but with the configuration of the present invention, This has the effect of reducing the overall weight and overall size of the device.

[Brief explanation of the drawing]

The figure is a partially cutaway vertical front view showing the main parts of the resin sealing device for semiconductor elements according to the present invention, and shows the state when both the upper and lower molds are clamped and when the resin material is pressurized by the plunger. Explanation of symbols, 1...Fixed upper mold, 2...Movable lower mold, 3...Pot, 4...Plunger, 5...
Cavity, 6... Resin material transfer passage, 7...
Plunger holder, 8... Vertical reciprocating sliding mechanism, 9... Elastic pressing member, 12... Servo motor, 13... Horizontal rotating shaft, 14... Rotating nut member, 15... Screw shaft, 17... Load cell, 17 ₁ ... pressure detection signal, 18 ... automatic control circuit, 18 ₁ ... control signal.

Claims (1)

[Scope of utility model registration request] An upper mold, a lower mold disposed opposite to the upper mold, a plurality of pots disposed on the lower mold, plungers for pressurizing a resin material fitted in each pot, and each plunger can be freely operated. A resin sealing device for a semiconductor element, comprising a plunger holder fitted and supported, and a plunger reciprocating sliding mechanism for vertically reciprocating each of the plungers through the plunger holder, the plunger The vertical reciprocating sliding mechanism is composed of an electric screw jack mechanism using a servo motor as a driving source, and a mechanism for detecting the pressing force on the resin material is provided between the screw shaft in the electric screw jack mechanism and the plunger holder. 1. An apparatus for resin-sealing a semiconductor element, characterized in that a load meter is attached thereto, and the torque control and forward/reverse rotation switching operation of the servo motor are automatically performed based on a detection signal from the load meter.