JPS6294317A - Molding apparatus - Google Patents

Abstract

PURPOSE:To enable to execute the replacement of plungers efficiently, by mounting a plunger sliding in a pot at the state where it has a head as pressing part and a rod supporting the same, and the head is mounted so as to be freely removable from the rod, and capable of free movement in a required range towards a rod shaft and vertical direction. CONSTITUTION:A plunger 20 has a structure wherein a head 21 and a rod 22 supporting it are mounted to a holder in long shaft form. Two bolts 24 are fixed to the head 21 through a collar member and the head 24a of the bolt 24 is at the state taken in a spot facing 22a formed on the rod 22. In the rod a collar penetrating hole 22b is formed, and the collar member 25 and this collar penetrating hole 22b have a gap, for example about 0.2mm to 0.5mm. Therewith, the head 21 is at the state capable of free movement towards the shaft direction and vertical direction of the rod 22. Therefore at the time of plunger penetration into a pot, the operation for removing and positioning a mold is unnecessitated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a technology that is effective when applied to molding technology, particularly to pancage molding technology for resin-sealing semiconductor devices.

[Background Art] In a package molding process for a resin-sealed semiconductor device, a molding device having a mold in which a cavity is formed is used, and a lead frame, which is a molded object, is held between the molds and the cavity is filled. By injecting resin as a molding material into the cane, a predetermined shaped cane package is formed.

By the way, the mold of the above-mentioned molding apparatus is provided with a pot into which tablet-shaped resin is poured, and the resin is injected into the cavity by pressure from a plunger sliding on the inner surface of the pot. It has been known.

Here, as described above, the side surface of the plunger has the property of becoming worn due to repeated sliding motion with the pot. As this wear increases, a gap widens between the inner surface of the pot and the plunger, allowing air to enter the inside of the resin pressed by the plunger. If resin is injected into the cavity in this state, voids will occur in the molded pancage body. Furthermore, due to the enlargement of the gap, the pressure resistance of the plunger against the resin may increase, resulting in insufficient molding. For this reason, it becomes necessary to replace the plunger with a new one every predetermined number of molding steps.

However, in a molding machine with the above structure, when replacing the plunger, first open the mold, loosen the set screw on the mold to free the mold, and then move the mold to replace the pot. It was being positioned with the plunger. If the plunger is installed while the positional relationship between the pot and the plunger is incorrect, the plunger or the pot may be damaged, or the sliding resistance may increase in some areas, accelerating wear. Become. Therefore, the positioning of the nibranja and the pound had to be done carefully, requiring a skilled technique.

However, the inventors have found that this causes a lot of time to be required to replace the plunger, and also causes a decrease in the workability of the package molding process.

In addition, in the plunger of the above structure, the parts that wear out, such as the plunger head and the rond, are all integrated, so the entire plunger must be replaced, which also increases the replacement cost of the plunger. was revealed by the present inventor.

An example of a detailed description of molding is Maruzen Co., Ltd., published on November 25, 1962,
"Integrated Circuit Handbook" P420-424.

[Object of the invention] The object of the invention is to efficiently replace the plunger.
- To provide the technology that can be used.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Summary of the Invention] A brief summary of typical inventions disclosed in this application is as follows.

That is, the plunger that slides inside the pot has a head that is a pressing part and a rond that supports it, and
The insertion of the plunger into the pot is facilitated by adding a molding device structure in which the head can be freely attached to and removed from the rond, and the head can freely move within a predetermined range in the direction perpendicular to the rond axis. Since there is no need to remove the mold and position it, the plunger can be replaced efficiently.

[Example] FIG. 1 is an enlarged partial sectional view showing the vicinity of a plunger of a molding device according to an embodiment of the present invention, and FIG. 2 is a schematic diagram showing the entire molding device.

The molding apparatus 1 of this embodiment is used for manufacturing semiconductor devices,
This is for performing package molding on a lead frame 2 as a molded object.

In this embodiment, the molded W1 has a fixedly mounted upper platen 3 and a movably mounted lower platen 4, both platens 3 and 4. It is supported by a plurality of pillars 5 that are vertically installed to surround it. The upper platen 3 is provided with a cylinder 7 whose reciprocating motion is controlled by a control section 6, and the lower platen 4 is provided with a mold opening/closing cylinder 9 whose reciprocating motion is controlled by a mold opening/closing control section 8.

An upper mold 10 is fixedly suspended from the upper platen 3 via a support 11, and a lower mold 12 is attached to the lower platen 4 while being supported by a support 13. Between the upper mold 10 and the lower mold 12,
As shown in FIG. 1, a cavity 14 is formed as a package molding section. Further, the lower mold 12 is formed with a cull 15 and a runner 16 that communicates the cull 15 with the cavity 14 as a resin receiver.

The runner 16 has a gate 17 formed in the vicinity of the cavity 14 in an inversely tapered shape with respect to the cavity 14, and is structured to increase the injection pressure of the resin 18.

A bot 19 is attached to a portion of the upper mold lO corresponding to the cull 15, and a plunger 20 shown in FIG. The structure is such that the resin 18 (tablet) in a softened state is pressed and injected into the cavity 14 through the runner 16 and gate 17.

The plunger 20 of this embodiment has a structure in which a head 21 and a rod 22 that supports the head 21 are attached to a long-axis holder 23. Two bolts 24 are fixed to the head 21 via a collar member 25.
The head 24a is a counterbore 22a formed in the rod 22.
It is currently housed in. A collar insertion hole 22b is formed in the nrad 22, and the distance between the collar member 25 and this collar insertion hole 22b is, for example, 0.2 mm to
It has a gap of about 0.5N, which allows the head 2
1 is in a state where it can freely move in a direction perpendicular to the axial direction of the rod 22. At this time, if the width of free movement is less than 0.2, it is insufficient as a transfer width for positioning, and 0.
．． If the width is more than 5 cranes, the mounting of the head 21 will cause some wobbling, so the above range of free movement is most appropriate.

A small resin injection hole 2 is provided on the pressing surface and side surface of the head 21.
1a and 21b are opened, and this resin injection hole 2
1a and 21b extend through the inside of the head 21 and into the inside of the rod 22.

The rod 22 to which the head 21 is attached is attached to the holder 2
The holder 23 is connected to the above-mentioned cylinder 7 provided on the upper part of the molded N1, and is configured to move the head 21 up and down.

Next, the operation of this embodiment will be explained.

When the upper mold 10 and the lower mold 12 are opened and the lead frame 2, which is the object to be molded, is placed in a predetermined position on the lower mold 12 with the pellet 26 and the wire 27 attached, the mold opening/closing cylinder 9 is operated under the control of the mold opening/closing control section 8,
The upper mold 10 and the lower mold 12 are closed with the lead frame 2 sandwiched therebetween.

Next, the cylinder 7 is operated under the control of the control unit 6, and the tablet-shaped resin 18 is pushed into the bot 19 by the plunger 20.
This causes the resin 18 to be pumped through the runner 16 and gate 17 and injected into each cavity 14 .

When the resin 18 in the cavity 14 hardens, the upper mold 10 and the lower mold 12 are opened, and the lead frame 2 whose package molding has been completed is taken out from the mold Wl.

After repeating the above-described molding process a predetermined number of times, the plunger 20, that is, the head 21, is replaced, and this is performed according to the following procedure.

First, the holder 23 is removed from the cylinder 7, and then the holder 23 is unscrewed and the rod 22 is removed from the holder 23.
are separated. Next, a wrench (not shown) is inserted into the counterbore 22a of the rod 22, the bolts 24 fastened to the head 21 are loosened, and the head 21 is separated from the rod 22.

Next, attach a new head 2 to the rod 22 by reversing the procedure above.
1 is attached. As described above, according to this embodiment, it is not necessary to replace the entire plunger 20, and only the head 21, which is a consumable part, needs to be replaced.

Further, the rod 22 is attached to a holder 23, and this holder 23 is attached to the cylinder 7, and the plunger 20,
That is, the replacement of the head 21 is completed.

At this time, since the head 21 is capable of free movement of about 0.2 to 0.5 cm in this embodiment with respect to the inner surface of the bot 19, the upper mold 10 or the lower mold 12 is temporarily set in a free state. There is no need to spend time positioning the plunger 20 with respect to the bot 19, and therefore the plunger 20, that is, the head 21 can be replaced extremely easily.

After replacing the head 21 in this way, the first molding process is performed. At this time, when the resin 18 is pressed by the head 21, a part of the resin l□ 8 is formed in the head 21 due to the pressing force. The inside of the head 21 and the inside of the rod 22 are filled through the injection holes 21a and 21b.

Since this resin 18 is a thermosetting resin, it starts curing when heated to a predetermined temperature, and after being completely cured, it plays a role in fixing the head 21 and rod 22 in a predetermined positional relationship.

In this way, since the plunger 20 used in this embodiment is sometimes in a free state when installed after replacement, the head 20 can be easily installed without requiring a long time positioning work.
can be inserted into the pot 19, but after the initial molding process, the resin 18 filled with the pressing force into the resin injection holes provided in the head 21 and the rod 22 hardens, and the head 21 and the rod Since the head 22 is fixed at an optimal position, the head 21 does not shake even if the molding process is repeated later, and the molding process can be performed with high reliability.

[Effects] (1) The plunger that slides inside the pot has a head that is a pressing part and a rod that supports it, the head is detachable from the rod, and the head is arranged in a direction perpendicular to the rod axis. By creating a molding device structure that allows free movement within a predetermined range against the mold, there is no need to remove the mold and position it when inserting the plunger into the pot. can be exchanged efficiently.

(2) Since the head, which is the pressing part, is constructed as a separate body, only the worn head needs to be replaced, and the cost of replacing the plunger can be reduced.

(3) A resin introduction hole was opened in the head, and the resin introduction hole communicated with the inside of the head and extended to the inside of the rod, thereby performing the first molding process after replacing the plunger. Later, the resin filled in the resin injection holes provided in the head and rod hardens and fixes the head and rod in the optimal position, so even if the molding process is repeated later, the head will not wobble. , a highly reliable molding process can be performed.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the Examples and can be modified in various ways without departing from the gist thereof. Nor.

[Field of Application] In the above explanation, the invention made by the present inventor was mainly applied to the field of application, which is a molding apparatus used for molding a package of a so-called resin-sealed semiconductor device, but the present invention is not limited to this. It is not something that is done, but
For example, this technique is also effective when applied to a molding apparatus that molds packages for other electronic parts or mechanical parts.

[Brief explanation of drawings]

FIG. 1 is an enlarged partial sectional view showing the vicinity of a plunger of a molding device according to an embodiment of the present invention, and FIG. 2 is a schematic diagram showing the entire molding device. 1... Molding device, 2... Lead frame, 3...
Upper platen, 4... Lower platen, 5... Support column,
6... Control unit, 7... Cylinder, 8... Mold opening/closing control unit, 9... Mold opening/closing cylinder, 10... Upper mold, 11
...Support, 12...Lower die, 13...Support, 14...Lower platen, 15...Cull, 16...
・Runner, 17...Gate, 18...Resin, 19.
... Pot, 20 ... Plunger, 21 ... Head, 21a, 21b ... Resin injection hole, 22 ... Rod, 22a ... Counterbore, 22b ... Collar insertion hole,
23... Holder, 24... Bolt, 24a... Head, 25... Collar member, 26... Pellet, 27
..."Wire. Figure 1 Figure 2

Claims (1)

[Scope of Claims] 1. A plunger that slides inside a pot has a head that is a pressing part and a rod that supports the head, and the head is detachable from the rod, and the head is detachable from the rod. 1. A molding device characterized in that the molding device is attached to a rod axis so as to be able to freely move within a predetermined range in a direction perpendicular to the rod axis. 2. A bolt having a collar member interposed in the head is fastened, and the head of the bolt is accommodated in a counterbore formed in the rod. The molding device described in Section 1. 3. The molding apparatus according to claim 1, wherein the head is provided with a resin introduction hole, and the resin introduction hole communicates with the inside of the head and extends to the inside of the rod. .