JP2774965B2 - Resin sealing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] The present invention relates to a resin sealing device for a semiconductor device or the like, with the aim of reducing the hydraulic system of the sealing device by the transfer molding method to reduce the weight of the entire device. A plurality of sliding guide rods supported by a board and a fixed board, a first movable board and a lower mold which are slidably fitted to the sliding guide rods and an upper mold is fixed to a lower surface. A second movable platen fixed to the upper side,
At least one pneumatic cylinder supported on the fixed platen and linearly driving the first movable platen, and a plurality of mold clamping hydraulic cylinders mounted on the base platen and linearly driving the second movable platen, It comprises a resin injection hydraulic cylinder into which resin is poured from the side of the lower mold, and at least one board supporting means for stopping and fixing the linearly driven first movable board.

[Industrial applications]

 The present invention relates to a resin sealing device.

In recent years, with the miniaturization and high-density mounting of electronic devices, the progress of the electronic component industry has been remarkable.

Among the electronic components, semiconductor components, which are classified alongside general electronic components, are particularly remarkable in the development of semiconductor devices centering on integrated circuits (ICs).

And, as the use of ICs has been used in all fields, the amount and quantity of IC production has increased dramatically.

Along with this, the importance of manufacturing techniques in a series of manufacturing processes from a wafer stage to finishing as a semiconductor device into a product is increasing more and more.

In the IC manufacturing process, the wafer process from the wafer stage to the formation of many fine elements, cutting into chips, bonding the chips to frame-shaped terminals called lead frames, and connecting them with fine wires In the wire bonding process, the productivity has been improved by increasing the dimensions of the wafer, miniaturizing the circuit pattern, increasing the connection speed of the bonder, or automating and unmanning the entire process. I have.

On the other hand, semiconductor devices, especially chip components intended for miniaturization, etc., are generally sealed by various methods in order to protect elements.

However, except for the case of being used for a special purpose, resin encapsulation has recently been frequently used due to element passivation (passivation) technology and improvement of characteristics of an encapsulating resin.

An epoxy resin, a silicone resin, a phenol resin, or the like is used as the sealing resin, and a mold, casting, dipping, potting, or the like is used as the sealing method depending on the purpose.

Because of good manufacturing efficiency and low cost, resin encapsulation by a mold, among them, resin encapsulation by a transfer molding method is often used.

The transfer molding method is a molding method developed as a molding method similar to the injection molding method performed on thermosetting resin molding materials, and the dimensional accuracy and molding efficiency of the molded product, the life of the mold, etc. are good, Material loss is large, resin molding pressure is high, and therefore mold clamping pressure is large,
Hard to use for electronic components.

On the other hand, the low-pressure encapsulation molding method, which is called the encaps molding method in the transfer molding method, has a low molding pressure, and is attracting attention as a molding method for resin sealing of electronic components, mainly for semiconductor devices such as ICs. ing.

It is said that the price of electronic components is determined by a sealing process, especially for ICs, and the importance of resin sealing technology and a sealing device for performing the same is increasing.

[Conventional technology]

Taking a resin-sealed semiconductor device as an example of a resin-sealed part by a transfer molding method, the resin sealing performed here is such that, for example, a chip is fixed to a mounting portion called a header, and an inner lead is formed. This is performed by setting a lead frame which is a thin metal plate frame-shaped terminal wire-bonded to a terminal portion called by a gold wire or the like in a sealing mold, and pouring sealing resin.

FIG. 2 is an explanatory view of an example of a resin sealing device by a conventional transfer molding method.

In this figure, the resin sealing device employs a transfer molding method, and hydraulic pressure is used for both the mold clamping operation and the resin injection operation.

That is, an upper mold 2a and a lower mold 2b, and a mold clamping hydraulic cylinder 3 housed in the frame 17 for moving the lower mold 2b up and down, and a hydraulic tank for driving the mold clamping hydraulic cylinder 3 13 and a hydraulic pump 14, and a hydraulic system such as a hydraulic cylinder 4 for resin injection.

These hydraulic systems are sequence-controlled by, for example, a control device 15 equipped with a microcomputer.

First, an upper mold 2a is fixed to a lower surface of a fixed platen 6 supported by four sliding guide rods 5.

Next, the holes at the four corners of the movable platen 7 fit into the four sliding guide rods 5 and slide up and down.

On the upper surface of the movable platen 7, the lower mold 2b is placed so as to be in close contact with the upper mold 2a.

A piston rod 16 of the hydraulic cylinder for mold clamping 3 housed in a frame 17 is connected to the lower surface of the movable platen 7 so as to move up and down along the sliding guide rod 5. I have.

On the other hand, the resin injection cylinder 4
Are provided, and the two molds 2 that penetrate through the fixed platen 6
Inject resin into a and 2b.

At the time of resin sealing, for example, a lead frame on which a semiconductor element or the like (not shown) is mounted is set in the lower mold 2b, and the movable platen 7 is raised by the hydraulic cylinder 3 for mold clamping.

When the lower mold 2b is tightly fitted to the upper mold 2a, the movable platen 7 is stopped from rising, and the sealing resin material is injected from the resin injection hydraulic cylinder 4 into the upper and lower molds 2a and 2b, and the molding is completed. Done.

In this resin encapsulation, in order to increase productivity, a lead frame in which a plurality of elements are mounted and a plurality of elements are connected is called a sheet.
Further, for example, a plurality of sheets are held by a holding jig of a lead frame called a loading frame, and molding is performed at a time.

Therefore, the resin is injected at a pressure of, for example, several tens of kg / cm ² , but the total pressure is several tons.

Therefore, the mating surface between the molds 2a and 2b, which are divided into upper and lower parts, or the mating surface between the two molds 2a and 2b and a lead frame (not shown) sandwiched between them, may cause leakage of the injected resin. And also from the point of protecting the mold,
Hundred kg / cm ^2, the total pressure should be clamping at a higher pressure of up to several tens ton~ several hundred ton.

On the other hand, when setting a lead frame or the like or taking out a molded product, the molds 2a and 2b divided into two
For example, if it does not open at least about 150mm, it will hinder work.

As described above, in the conventional resin molding apparatus using the transfer molding method, the hydraulic system used for moving the movable platen 7 up and down even when the pressing force output by the mold clamping hydraulic cylinder 3, that is, the cylinder output is large. Even if the piston rod 16 to be moved in and out, that is, the stroke is long, the device is very large and heavy.

[Problems to be solved by the invention]

As described above, in order to obtain a high molding pressure, the hydraulic system in the conventional resin molding apparatus using the transfer molding method generates a higher mold clamping pressure, and is divided into two parts from the viewpoint of workability. To increase the opening distance of the mold, it is a large and heavy hydraulic system.

Furthermore, when trying to obtain a large pressing force with a hydraulic cylinder, the piston speed tends to decrease,
In order to move a long stroke in a short time, a large-scale hydraulic device is also required.

As described above, in the conventional resin sealing device that operates only by the hydraulic system, there has been a problem that a series of sealing operation time becomes longer or the device becomes large-scale when the operation time is shortened.

Further, there is a problem of contamination caused by handling a large amount of oil, and there is a troublesome problem in moving and maintaining the apparatus.

[Means for solving the problem]

The above-mentioned problem is caused by a plurality of sliding guide rods supported by a base plate and a fixed plate facing each other, and slidably fitted to the sliding guide rods, and the upper mold is fixed to the lower surface. The first movable plate and the lower mold that are fixed to the upper surface of the second movable plate, at least one pneumatic cylinder supported by the fixed plate and linearly driving the first movable plate, and a base plate A plurality of mold clamping hydraulic cylinders that are mounted and linearly drive the second movable platen, a resin injection hydraulic cylinder that pours resin from the lower mold side, and the linearly driven first movable platen At least one to stop and fix
This can be achieved by a resin sealing device composed of individual board support means.

[Operation] In the resin sealing device according to the present invention, the load is small but the stroke is small, in contrast to the conventional resin sealing device that uses a hydraulic cylinder as a driving source for tightening and releasing the mold. Combines a pneumatic cylinder suitable for long tasks with high speed and a hydraulic cylinder suitable for tasks with large loads but short strokes, making the most of each performance and efficient The feature is that it can be sealed with resin, so that it is not necessary to use a large-scale hydraulic device.

That is, in the present invention, the load is small, but the operation with a large stroke is performed by the pneumatic cylinder,
Although the stroke is small, the operation requiring a large load is performed by the hydraulic cylinder.

This will be specifically described with reference to the operation explanatory diagram of FIG. 1 (B).

(B) of FIG. 2B shows the mold open state, and the two dies 2a and 2b are used to easily mount the lead frame 9 on which electronic components such as semiconductor elements are mounted, for example. It is arranged between two molds 2a and 2b which are greatly opened.

Next, in (b) of FIG.
The first movable platen 7a fixed to the upper mold 2a and the lower mold 2b are moved by a large stroke along the sliding guide rod 5.
Is brought close to the closest distance immediately before the mold is fitted.

In this position, the first movable platen 7a is fixed by the plate support means 11.

Further, in (c) of FIG. 6B, the second movable platen 7b fixed to the hydraulic cylinder 3 for mold clamping is moved along the sliding guide rod 5 so as to apply a large load with a small stroke. Let it.

Then, the upper mold 2a and the lower mold 2b are completely fitted.

Thereafter, the sealing resin is poured from the resin injection hydraulic cylinder 4 into the cavities of the two molds 2a and 2b so that the resin is sealed.

Here, the first movable platen 7a driven by the pneumatic cylinder 10 only needs to be able to support the load required to move the first movable platen 7a and the upper mold 2a. This is equivalent to moving work, and the pneumatic cylinder 10 can perform the work with good responsiveness.

On the other hand, in the movement of the second movable platen 7b by the mold clamping hydraulic cylinder 3, not only the second movable platen 7b and the lower mold 2b are moved by a distance of several mm, but also the two molds 2a and 2b are moved. For example, it is necessary to tighten with a pressing force of tens of tons, and this is a work well suited to a hydraulic cylinder.

In this manner, in the present invention, efficient resin sealing can be performed by maximizing the performance of each of the pneumatic cylinder and the hydraulic cylinder.

〔Example〕

 FIG. 1 is an explanatory view of an embodiment of the present invention.

In FIG. 1A shown in a perspective view, the pneumatic cylinder 10 for driving the first movable platen 7a must support and move the first movable platen 7a weighing 220 kg and the upper mold 2a. A double-acting, single-rod, flange-type cylinder is used. The specifications of the cylinder are a maximum stroke of 180 mm, a cylinder output of 120 kg, and an average piston speed of 200 mm / sec.

Then, the piston rod was screwed to the fixed platen 6 with a mounting flange, and the piston rod was fixed to the first movable platen 7a through a hole opened at the center of the fixed platen 6.

As the board supporting means 11, a solenoid whose shaft is protruded by a magnetic force is used.

Then, when the first movable platen 7a moves and reaches a predetermined stop position, that is, when the upper mold 2a and the lower mold 2b reach a position close to the temporary fitting by approaching 0.5 mm, it synchronizes therewith. The shaft protrudes and fits into the support hole 12 to support the first movable platen 7a.

The hydraulic cylinder 3 for closing the mold that drives the second movable platen 7b has a maximum stroke of 3 mm and a cylinder output of 15 tons.
Using a single rod flange type cylinder, the second movable platen 7b
Four are arranged on the lower side of the, so that a total clamping force of 60 tons can be obtained.

As the resin injection hydraulic cylinder 4, a hydraulic cylinder having a sealing resin injection pressure of 60 kg / cm ² was used.

Then, the sealing resin can be injected into the cavities of the two molds 2a and 2b through the base plate 1 and the second movable plate 7b.

The resin sealing operation process followed the procedure of the operation explanatory diagram shown in FIG. 9B, and the procedure was stored in the control device 15 as an operation sequence, and after the sample was set, automatic operation was possible.

The resin-encapsulated sample was evaluated by performing resin encapsulation using a lead frame 9 on which a semiconductor element chip was mounted and set on a holding jig loading frame (not shown).

As a result, the movement of the first movable platen 7a by the pneumatic cylinder 10 is a distance of 150 m when the distance between the two molds 2a and 2b is open.
It was confirmed that a stroke of approximately 150 mm approaching from m to 0.5 mm could be operated in less than 1 second, and a stroke of separating from 0.5 mm to 150 mm in approximately 1 second.

This operation time is two times the time performed by the conventional hydraulic cylinder.
It was one-third to one-third of the time.

In addition, in the mold clamping by the mold clamping hydraulic cylinder 3, since the distance between the two molds 2a and 2b is close to 0.5 mm, the moving stroke may be very small, and after the hydraulic system is activated. It was confirmed that the maximum clamping force was reached in about 1.8 seconds.

The same 1.8 seconds of the mold closing time were applied to the mold opening time when the interval between the two molds 2a and 2b was once opened to 0.5 mm after the resin sealing was completed.

Further, even if the mold clamping hydraulic cylinder 3 and the resin injection hydraulic cylinder 4 are combined, the capacity of the hydraulic pressure source to be driven may be small, the hydraulic tank 13 has a small capacity, and therefore only one hydraulic pump 14 is required. It is.

Accordingly, the rack 17 can accommodate the hydraulic tank 13, the hydraulic pump 14, and the control device 15, and is approximately one-half the installation area as compared with a conventional resin sealing device having almost the same capacity. And less than about two-thirds of the weight.

In this case, the vertical type device is used, but the characteristics of a combination of a pneumatic cylinder and a hydraulic cylinder can be exhibited even with a horizontal type device.

Also, various modifications can be made to the positional relationship, the number of components, and the like of the pneumatic cylinder, the hydraulic cylinder for mold clamping, the hydraulic cylinder for resin injection, and the like, and various specifications.

Further, the board supporting means can be provided with a fixing means on the sliding guide rod, and various modifications are possible.

〔The invention's effect〕

As described above, in the conventional resin sealing device,
Not much load, but long stroke
The use of hydraulic pressure in the drive system not only increases the time required for one cycle of a series of sealing operations, but also makes the equipment heavy and bulky, resulting in oil contamination in the work environment due to the use of a large amount of oil. There were many factors that hindered the efficiency of the resin sealing process, such as difficulty in moving and maintaining.

On the other hand, according to the resin sealing device of the present invention,
The pneumatic and hydraulic cylinders are combined to take advantage of their good performance.

That is, an operation with a small load but a large stroke is performed by a pneumatic cylinder, and an operation with a small stroke but a large load is performed by a hydraulic cylinder.

Therefore, since the operation speed of the apparatus is high and the scale of the hydraulic system can be reduced, the problems of the conventional resin sealing apparatus can be solved, which greatly contributes to improving the efficiency of the resin sealing step.

[Brief description of the drawings]

FIG. 1 is an explanatory view of one embodiment of the present invention, and FIG. 2 is an explanatory view of an example of a resin sealing device by a conventional transfer molding method. In the drawing, 1 is a base plate, 2a is an upper die, 2b is a lower die, 3 is a hydraulic cylinder for mold clamping, 4 is a hydraulic cylinder for resin injection, 5 is a sliding guide rod, 6 is a fixed plate, and 7a is a fixed plate. The first movable plate, 7b is a second movable plate, 9 is a lead frame, 10 is a pneumatic cylinder, 11
Is a board support means, 12 is a support hole, 13 is a hydraulic tank, 14 is a hydraulic pump, 15 is a control device, and 16 is a piston rod.

Claims (1)

(57) [Claims] 1. A plurality of sliding guide rods (5) supported by opposed base plate (1) and fixed plate (6).
The first movable platen (7a) and the lower mold (2b), which are slidably fitted on the sliding guide rod (5), and the upper mold (2a) is fixed to the lower face, are attached to the upper face. The second movable platen (7
b) supported by the fixed platen (6), and the first movable platen (7
a) at least one pneumatic cylinder (10) for linearly driving a) and a plurality of mold-clamping hydraulic cylinders (10) mounted on the base board (1) and linearly driving the second movable board (7b). 3), a resin injection hydraulic cylinder (4) into which resin is poured from the side of the lower mold (2b), and at least one board supporting means for stopping and fixing the linearly driven first movable board (7a). (11) A resin sealing device comprising: