JPH03220739A - Resin sealing molder for semiconductor element - Google Patents

Abstract

PURPOSE:To prevent the generation of damage of a mold by installing an actuator exclusively designed for the knock out operation of at least either lower type or upper type ejector plate on the one hand and detecting the presence of a foreign matter during mold clamping under the condition where mold clamping force is reduced to substantially zero. CONSTITUTION:A resin-sealing molder for semiconductor elements which performs knockout operation with ejector plates 21 and 22 during mold break, is provided with mold position detection sensors 10 and 11, which are designed to detect a mutual approaching distance of molds in order to detect a foreign matter clamped by an upper mold 9 and a lower mold 8 during mold clamping and a means 36 which maintains a mold clamping force required until the approaching distance of the sensors 10 and 11 reaches a specified distance which allows mold clamping operation, substantially at zero based on signals transmitted from the sensors 10 and 11. Furthermore, the molder is provided with an actuator 6 which performs knockout operation of the ejector plat 22b on the one hand at least selected out of the upper mold 9 and the lower mold 8. This construction makes it possible to prevent the generation of damage on the mold during foreign matter detecting operation.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a resin encapsulation molding machine for semiconductor elements that encapsulates semiconductor elements mounted on a lead frame, and particularly relates to a resin encapsulation molding machine with an improved foreign object detection mechanism. Regarding.

[Conventional technology]

2. Description of the Related Art Conventionally, a foreign matter detection mechanism in a resin encapsulation molding machine for semiconductor elements of this type will be explained with reference to the drawings.

FIG. 3 is a front view of a conventional resin encapsulation molding machine for semiconductor devices. In the figure, a platen 1 is movable up and down, and is slidably fitted into four columns 3 erected on the bed 2. 4 is a crown held at the upper end of the column 3, 5 is a transfer cylinder equipped on the crown 4, 6 is a plunger of the transfer cylinder 5, 7 is a hydraulic cylinder that drives the platen 1 and the lower mold 8, and 9 is an upper mold ,1o,1
Reference numeral 1 denotes a mold position detection sensor such as a proximity switch installed to detect foreign matter when the upper mold and lower mold are clamped.

The internal structure of the mold is 12,] 3 is a heater 14,]
5 and has cavities 17 and 18 forming a package 16a in which a semiconductor element (not shown) on a lead frame (not shown) is sealed with resin. ]9.20 is the package 16 after molding.
ejector bins 22b and 21 for extruding a from the cavity] 7.18 are used by springs 23 in the upper mold 9 and by ejector rods (not shown) at the lowest end of the mold in the lower mold 8, respectively. Ejector bin 20. To the ejector plate 1 that moves one to the sliding nizhief 1, 24 is a support rod of the compression spring 23, 26
．． 27 is a stopper that limits the vertical position of the ejector play 1, 28.29 is a support block, and 30.3 is a cord.
is the mold mounting plate. Further, 32 and 33 are knockers 1 to blocks and ejector rods for pushing up the ejector plate 22b when the upper mold 9 and the lower mold 8 are clamped.

Next, a method for detecting foreign matter using the resin encapsulation molding machine for semiconductor devices configured as described above will be described.

FIG. 4 is a sectional view showing a conventional foreign object detection mechanism. In the figure, even if the chip 4.3a that is tie-bonded on the lead frame 42a is out of its normal position due to insufficient amount of adhesive resin, etc., the mold clamping force is not applied to the original position before mold clamping. Loosen the mold clamping force (the compression force of the spring 23 is approximately 3
Low-pressure mold clamping is being performed (with a force slightly higher than 0.000 kg), and the upper mold 9 is placed within a predetermined distance (approximately 0.1 mm apart from the mold clamped state) where the mold position detection sensor 10.11 is located. Unless it is detected that the lower mold 8 approaches, the mold clamping force is not increased to its original level.

[Invention or problem to be solved]

In the above-described conventional resin encapsulation molding machine for semiconductor devices, the mold clamping force when detecting a foreign object must be set to the force necessary to resist the spring 24 in order to push up the ejector plate 22b. Fine adjustment of the mold clamping force setting is difficult with hydraulic drive, and it is necessary to set the mold clamping force above a predetermined value when foreign matter is detected.

Therefore, if only a part of the chip 43b is sandwiched between the upper mold 9 and the lower mold 8 as shown in the cross-sectional view of FIG. As shown in the sectional view of FIG. 6, there is a drawback that damage 44 is caused to the mold.

As a result, as shown in the cross-sectional view of FIG. 7, a thin burr 45 was attached to the lead frame 42c molded with this mold due to the resin leaking from the cavity, which caused poor solder plating. . FIG. 7 shows a state in which this thin burr 45 remains on the lead frame.

[Means to solve the problem]

The present invention has a mold position detection sensor for detecting foreign matter sandwiched between the upper mold and the lower mold when the mold is closed, and for detecting the mutual approach distance of the molds, and also has a mold position detection sensor for detecting a foreign object sandwiched between the upper mold and the lower mold when the mold is closed, and also has a mold position detection sensor for detecting a foreign object sandwiched between the upper mold and the lower mold when the mold is closed. A resin encapsulation molding machine for semiconductor elements that operates, comprising means for maintaining mold clamping pressure at approximately zero using a signal from the sensor until the approach distance of the sensor reaches a predetermined distance for performing main mold clamping, The present invention is also a resin encapsulation molding machine for semiconductor devices, which is equipped with an actuator for performing a knockout operation of an ejector plate of at least one of an upper mold and a lower mold.

〔Example〕

Next, the present invention will be explained with reference to the drawings. FIG. 1 is a front view of a resin encapsulation molding machine for semiconductor devices according to a first embodiment of the present invention. In this figure, the same members as those in the conventional system shown in FIG. 3 are denoted by the same reference numerals, and detailed description thereof will be omitted. In the figure, the ejector plate 22a is pushed down by a cylinder rod 35 of a cylinder 34 when the mold is opened. Further, 36 is a compression spring that pushes up the ejector plate 22a, and 37 is a stopper that determines the upper limit position of the ejector plate.

With this configuration, the ejector plate 22
Since a is always pushed up by the compression spring 36, the conventional ejector plate 22 shown in FIG.
The force to resist the spring 23 that pushes down b is no longer required,
Therefore, there is no need for fine adjustment, and the mold clamping force when detecting foreign objects is approximately O
It is possible to set the value to a value close to kg, so that even if only a part of the chip 43a is sandwiched between the upper mold 9 and the lower mold 8 as shown in the cross-sectional view of FIG. 4, the chip 43b will not be crushed by the mold clamping force. Foreign matter can be detected without any problems, and damage to the mold can be prevented.

In this embodiment, the knockout operation in which the ejector plate 22b of the upper die is pushed down by the cylinder 34 has been described, but it is of course possible to perform the knockout operation in which the ejector plate 21 of the lower die is pushed up by changing the mounting position of the actuator. It is.

FIG. 2 is a front view of Embodiment 2 of the present invention. In the figure, the same members as in Figure 1 are designated by the same reference numerals.
Detailed explanation will be omitted. In the figure, the ejector plate 22a is pushed down by a rod 41 via wedges 40 at the tips of three shafts of a motor 38 when the upper and lower molds are opened.

In this embodiment, since the motor 38 is used, the position and speed of the ejector plate 22a can be freely set, and there is an advantage that damage to the package 16a can be minimized when the package 16a is knocked out.

〔Effect of the invention〕

As explained above, the present invention is equipped with a dedicated actuator that performs the knockout operation of the ejector plate of at least one of the upper mold and the lower mold of a resin encapsulation molding machine for semiconductor devices, and detects foreign objects during mold clamping. By applying a force of approximately 0 kg, it is possible to prevent damage to the mold and prevent resin burrs from forming on the lead frame.

[Brief explanation of drawings]

Fig. 1 is a front view of Embodiment 1 of the present invention, Fig. 2 is a front view of Embodiment 2 of the invention, Fig. 3 is a front view of a conventional resin encapsulation molding machine for semiconductor elements, and Fig. 4 is a conventional 5 is a sectional view illustrating foreign object detection by a conventional resin encapsulation molding machine. FIG. 6 is a sectional view illustrating a damaged state of a mold by a conventional resin encapsulation molding machine. FIG. 7 is a sectional view of a package using a conventional damaged mold. 1...Platen, 2...Bed, 3...Column,
4...Crown, 5...Transfer cylinder, 6
... Plunger, 7... Hydraulic cylinder, 8... Lower die, 9... Upper die, 10.11... Mold position detection sensor, 12°13... Chase block, 14. 15・
...Heater, 16a, 16b--Package, 17.
18-... Cavity, 19.20... Ejector pin, 21° 22a, 22b... Ejector plate,
23...Spring, 24...Support rod, 25...
Compression spring, 26.27...stopper, 28.2
9...Support block, 30.31...Mold mounting plate, 32...Knockout block, 33...Ejector rod, 34...Cylinder, 35...Cylinder rod, 36...Compression Spring, 37... Stopper, 38... Motor, 39... Shaft, 40...
・・Wedge, 41・2・Rod, 42a, 42b, 4
2cm lead frame, 43a, 43b, 43cm
Chip, 44--damaged, 45--thin. 0 Figure 6 Figure 7 4 Leap injury i6b: Package 42C: l Nordoff L, -Otsu 43C nap 45, book basso

Claims (1)

[Claims] 1. A mold position detection sensor is provided to detect a foreign object sandwiched between the upper mold and the lower mold when the mold is closed, and is used to detect the mutual approach distance of the molds, and an ejector is provided when the mold is opened. In a resin encapsulation molding machine for semiconductor devices that performs a knockout operation using a plate, the mold clamping pressure is maintained at approximately zero by a signal from the sensor until the approaching distance of the sensor reaches a predetermined distance for performing main mold clamping. 1. A resin encapsulation molding machine for semiconductor elements, characterized by comprising means. 2. The resin encapsulation molding machine for semiconductor devices according to claim 1, further comprising an actuator for performing a knockout operation of at least one of the ejector plates of the upper mold and the lower mold.