JP2858942B2 - Resin sealing method and resin sealing device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a resin sealing method and a resin sealing device.

(Prior Art) In a transfer molding machine used for sealing an IC chip, a multi-plunger mold in which a plurality of pots are arranged in a mold is frequently used. In the resin sealing device using the multi-plunger mold, when filling the cavity with the molten resin, it is important to fill the resin with a uniform filling pressure for each cavity.

As a method of obtaining this uniform filling pressure, a method of providing an equal pressure unit in a pressing mechanism for pressing each plunger so that all the plungers fill the molten resin with an equal pressure, or connecting the pots with a pot communication path. In this method, the molten resin communicates between the pots to obtain an even pressure.

FIG. 5 shows an example in which a constant pressure unit is provided in the pressing mechanism of the plunger. In the figure, 10 is an upper mold, 12 is a lower mold, 14 is a pot, and 16 is a plunger. The plunger 16 is pushed by a constant pressure unit 18, and the constant pressure unit 18 is pushed and driven by a cylinder 20. The constant pressure unit 18 presses the plunger 16 by hydraulic pressure, and communicates with the hydraulic cylinders 18a to generate an equal pressing force.

On the other hand, FIG.
This is an example of using a mold that communicates with. In this method, when the tablet put into the pot 14 is melted and the plunger 16 pushes up the molten resin, the pot communication paths 14a allow the pots 14 to communicate with each other, and the communication pressure equalizes the resin pressure for all the cavities. . Therefore, in the case of this method, it is not necessary to provide the pressing mechanism of the plunger 16 with an equal pressure unit.

(Problems to be Solved by the Invention) As described above, there are roughly two methods for equalizing the filling pressure of the resin into the cavity.
In the case of the resin sealing device of the type shown in FIG. 5 in which 14 is provided independently, the pressure equalizing unit 18 must be provided separately, and the mechanism becomes complicated. In addition, the sliding resistance of the plunger 16 is
If they are different from each other, there is a problem that the resin pressure with respect to the cavities varies and is not uniform.

Further, in the case of the apparatus in which the pots 14 are communicated with each other through the pot communication path 14a shown in FIG.
Since the molten resin first flows into the pot communication path 14a and then reaches the gate, there is a problem that the timing when each cavity is filled with the resin varies. That is, since the communication between the pots 14 causes the resin to flow into portions where the resin easily flows when the resin injection is started, the flow of the resin to each cavity varies. All the molten resin finally communicates and the final filling pressure is
However, since the flow of the resin varies, there is a possibility that a cavity with insufficient resin filling may occur in some cases.

Therefore, the present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a resin sealing device using a multi-plunger mold in which pots are communicated with each other by a pot communication passage. An object of the present invention is to provide a resin sealing method and a resin sealing device capable of making the flow of resin uniform and the filling pressure of resin uniform.

(Means for Solving the Problems) The present invention has the following configuration to achieve the above object.

That is, in the resin sealing method of using a multi-plunger mold equipped with a plurality of pots and plungers, filling the resin melted in the pots by applying resin pressure with a plunger into a cavity and sealing the cavities, A pot communication path is provided for communicating between the pot communication paths, and a blocking / opening mechanism for blocking / opening the pot communication path is provided. When the resin is started to be injected into the cavity from the pot, the pot communication path is provided by the blocking / opening mechanism. And injecting resin into the cavity independently from each of the pots, opening the pot communication path by the shutoff opening mechanism, and applying resin pressure to the cavity to charge the resin. I do.

Further, in a resin sealing device having a plurality of pots and plungers, a pot communication path that communicates with each of the pots is provided, and the pot communication path is shut off so that resin can be injected into the cavity independently for each of the pots, An opening / closing mechanism of the pot communication path for opening the pot communication path and uniformly applying the resin pressure to the cavity is provided.

(Function) When the molten resin is pushed out of the pot into the cavity by the plunger, the pot communication path is shut off by the opening / closing mechanism of the pot communication path during the initial period of the resin filling, and each pot is set to the cavity set in advance for each pot. When the resin flows and is filled, and when the cavity is filled with a certain amount of resin and the pot communication path is opened by the shutoff / opening mechanism, the molten resin between the pots communicates, so that the pressing force of the plunger is reduced by each cavity. And then the resin is filled under uniform pressure.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a sectional view showing a configuration of a resin sealing device according to the present invention.

The resin sealing device of the embodiment has an upper mold 10 which is a resin molding portion.
And a lower mold 12, a top platen 30 and a moving platen 32 that support these molds, and a pressing mechanism that fills the cavity of the mold with the molten resin by the plunger 16.

The pressing mechanism of the embodiment is driven by a servomotor 40, and a plunger holder 17 for supporting a lower portion of the plunger 16.
A push plate 42, a ball screw 44 attached to the lower surface of the push plate 42, a nut 46 screwed to the ball screw 44, a pulley 48 fitted externally to the nut 46, and a drive shaft of the servo motor 40. It has a fixed pulley 49 and a timing belt 50 that connects between the pulley 48 and the pulley 49.

The pulley 48 is rotatably supported by the fixed plate 52, is rotated forward and reverse by the servomotor 40, advances and retreats the ball screw 44 screwed to the nut 46 from the fixed plate 52, and pushes the pushing plate 42.

The guide shaft 54 is fixed from the lower surface of the push plate 42 toward the fixed plate 52, and the tip of the guide shaft 54 is fixed to the fixed plate 52.
Slide into guide bush 56 penetrating 52 and push plate
42 is guided in parallel to the mold opening and closing direction.

The upper part of the plunger 16 supported by the plunger holder 17 slides into the pot 14 from below the lower mold 12. The figure shows a state where the resin tablet 60 is stored in the pot 14.

A cull portion 62 is provided at a position above the pot 14 of the upper mold 10, and adjacent cull portions 62 are communicated with each other by a pot communication passage 14a as in the conventional example. From each cull part 62, a runner and a gate are provided to communicate with the mold cavity.

Each of the above-described configurations has the same basic configuration as a conventional resin sealing device using a multi-plunger die, in which a pot is communicated with a pot communication path.

The feature of the resin sealing device according to the present invention is that, in the above configuration, the molten resin from another pot 14 does not flow into the adjacent pot 14 by blocking the pot communication path 14a halfway at the start of the resin injection. It is in.

For this reason, a shut-off pin 70 for blocking the resin path of the pot communication path 14a is slidably provided in a through hole vertically penetrating the upper mold 10. The shut-off pin 70 is provided at an intermediate position of each of the pot communication paths 14a communicating between the adjacent pots 14 so as to be able to shut off the pot communication paths 14a.

The shut-off pin 70 can be moved in the mold opening and closing direction by a spring 72.
The upper end of the upper mold 10 is always urged by the elastic force of the spring 72 so as to protrude from the parting surface of the upper mold 10.

A connecting pin 76 is provided upright on the lower surface of the outer edge of the support plate 74, and the connecting pin 76 is inserted into a through hole provided in the upper mold 10.

A lower connecting pin 80 is inserted into the lower mold 12 at the same position above and below the connecting pin 76 in parallel with the connecting pin 76. Lower connecting pin 80
A small diameter contact rod 78 extends from the upper end surface of the lower mold 12 so as to protrude freely from the parting surface of the lower mold 12. A spring 82 is extrapolated to the contact rod 78, and the contact rod 78 and the lower connecting pin 80
The lower connecting pin 80 is constantly urged downward by the elastic force of the spring 82 at one end thereof abutting the step connecting the two.

A small diameter contact pin 82 is provided below the lower end of the lower connecting pin 80.
Extends. The step between the lower connection pin 80 and the contact pin 82 contacts the plate 83 of the mold, and regulates the lower position of the lower connection pin 80 which is urged downward. The upper end surface of the contact rod 78 is set so as not to at least protrude from the parting surface of the lower mold 12.

On the upper surface of the pushing plate 42, a push-up pin 84 is provided at an extension of a contact pin 82 extending from each lower connecting pin 80.
Is established. FIG. 1 shows a state in which the push plate 42 is at the lower position, and the push-up pin 84 and the contact pin 82 are separated.

FIG. 3 shows a plan layout of the shut-off pin 70 in the upper mold 10. The figure shows an example in which the lead frame 90 is molded. At the center of the upper mold 10, a cull portion 62 is provided in accordance with the position of the cavity 92, and the pot communication passage is provided.
14a is provided so as to communicate the adjacent cull portion 62. The shut-off pin 70 is set to have a larger diameter than the flow path width of the pot communication path 14a so as to block the pot communication path 14a.

Each cavity 92 is communicated from the cull section 62 via a runner 94 and a gate 96.

 Subsequently, the operation of the above embodiment will be described.

First, the resin tablet 60 is put into the pot 14 of the lower mold 12, the lead frame 90 is set on the lower mold 12, and
The upper mold 10 and the lower mold 12 are clamped. FIG. 1 shows a state in which the upper mold 10 and the lower mold 12 are clamped.

The shut-off pin 70 protruding from the parting surface of the upper mold 10 is used to clamp the lower mold 12 when the upper mold 10 and the lower mold 12 are clamped.
The abutting force of the spring 72 blocks the pot communication path 14a.

The servo motor 40 is driven in synchronization with the melting timing of the resin tablet 60, and the pushing plate 42 is pushed upward via the ball screw 44.

The pushing plate 42 is pushed upward and the plunger
16 moves upward and pushes the molten resin toward the cull portion 62 side. The length of the push-up pin 84 and the contact pin 82 and the moving position of the pushing plate 42 are set in advance so that the push-up pin 84 does not contact the contact pin 82 while the molten resin is being pushed out to the cull portion 62. Keep it.

The state in which the push-up pin 84 and the contact pin 82 are not in contact is a state in which the shut-off pin 70 is in contact with the lower mold 12 and the pot communication path 14a is shut off. Therefore, when the plunger 16 extrudes the molten resin in this state,
The molten resin in each pot 14 starts to be filled into the cavity 92 via the runner 94 and the gate 96 which are in communication with each pot 14 independently of the molten resin in the other pots 14. In this way, at the time of starting the filling of the resin, the flow of the molten resin into and from the other pots 14 is blocked, and the resin is filled into the cavity 92 predetermined in each pot 14.

When the resin is filled, the pushing plate 42 continuously rises, and at the same time, the plunger 16 rises in the pot 14 and pushes the resin toward the cavity 92, but when the pushing plate 42 rises to a certain position, it is pushed up. The pin 84 contacts the contact pin 82. As a result, the lower connecting pin 80 moves upward against the elastic force of the spring 82, and the end face of the contact rod 78 comes into contact with the connecting pin 76 to move the support plate 74 upward. Support plate 74
When the is moved upward, the shut-off pin 70 is lifted, the cutoff of the pot communication passage 14a is opened, and the cull portion 62 is communicated by the pot communication passage 14a.

The cull portion 62 and the molten resin in the pot 14
When they communicate with each other, the filling pressure of the resin applied by each plunger 16 is shared by all the cavities 92, and the resin is filled with an equal filling pressure.

FIG. 2 shows a state in which the push-up pin 84 and the contact pin 82 are in contact with each other, the shut-off pin 70 is lifted, and the space between the pots 14 is all in communication, and the resin filling is completed.

As described above, the resin sealing device of this embodiment
When filling the 92 with resin, at the beginning of resin filling, the pot 14
The gap is cut off, and when the cavity 92 is filled with the resin to some extent, the pots 14 are communicated with each other to apply the resin pressure evenly to each cavity 92. In the present embodiment, the shutoff pin 70 is operated by providing the mechanism for opening and closing the pot communication path 14a to the pressing mechanism of the plunger 16 as described above, but it is of course possible to configure the mechanism with another mechanism. . For example, the shut-off pin 70 may be driven by another drive source.

The opening / closing timing of the pot communication path 14a can be appropriately set according to the moving height position of the push-up pin 84, the contact pin 82, and the pressing plate 42, but in the present embodiment, the pot communication path 14a is Set to open.

FIG. 4 is an explanatory view showing the movement position of the plunger 16 and the filling of the resin in the cavity 92 during the filling of the resin. In the same figure, the range A on the cavity 92 side is a range in which the resin is filled while the pot communication path 14A is shut off, and the range B is a state in which the pot communication path 14a is opened by moving the shut-off pin 70 upward and the uniform resin pressure is released. Is the range to be filled. At this time, plunger 16
Are located at positions A 'and B' in the figure.

Thus, the pot communication passage 14a is relatively slow in timing.
Is set to be open because the molten resin in each pot 14 is filled in each cavity 92 without going back and forth with the other pots 14 so that the amount of resin filled in the cavity 92 can be equalized, When filling the resin, the resin pressure is applied most immediately before the completion of filling in order to eliminate voids and the like, but it is most effective to equalize the filling pressure when the resin pressure is applied.
This is because the resin can be filled evenly in the 92 and good resin filling can be performed without causing leakage or the like. Of course, the opening timing of the pot communication path 14a may be set to an optimal timing as appropriate according to the product or the like.

As described above, the present invention has been described variously with reference to preferred embodiments. However, the present invention is not limited to the above-described embodiments, and it is needless to say that many modifications can be made without departing from the spirit of the invention. That is.

(Effects of the Invention) According to the resin sealing method and the resin sealing device according to the present invention, by using the above-described configuration, when molding using a multi-plunger mold in which the pots communicate with each other through the pot communication path. In addition, since the resin can be uniformly filled in each cavity, and the resin can be filled with an equal pressure, the resin molding can be performed with high accuracy.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a state in which a mold is clamped in one embodiment of a resin sealing device according to the present invention, FIG. 2 is a cross-sectional view when resin filling is completed, and FIG. 3 shows an arrangement of a shut-off pin. FIG. 4 is a plan view of the upper mold, FIG. 4 is an explanatory view showing the pot communication path being opened, and FIGS. 5 and 6 are cross-sectional views showing a conventional example of a resin sealing device using a multi-plunger mold. . 10 …… upper mold, 12 …… lower mold, 14 …… pot, 14a ……
Pot communication passage, 16 plunger, 42 pressing plate, 62 cull part, 70 shut-off pin, 76 connection pin, 80 lower connection pin, 82 contact pin, 84 ... push-up pin, 92 ... cavity.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) H01L 21/56 B29C 45/02

Claims (2)

(57) [Claims] 1. A resin sealing method for using a multi-plunger mold equipped with a plurality of pots and plungers, filling resin into a cavity by applying resin pressure by a plunger and sealing the resin in the pot. A pot communication path for communicating between the pots is provided, and a cut-off opening mechanism for shutting off and opening the pot communication path is provided. When the resin is started to be injected from the pot into the cavity, the cut-off opening mechanism Injecting the resin into the cavity independently from each of the pots by blocking the pot communication path, opening the pot communication path by the blocking and opening mechanism, and applying a resin pressure to the cavity to fill the resin. A resin sealing method. 2. A resin sealing device having a plurality of pots and a plunger, wherein a pot communication path communicating with each of the pots is provided, and the pot communication path is blocked to inject resin into the cavity independently for each of the pots. A resin sealing device, wherein a pot communication path blocking / opening mechanism is provided for opening the pot communication path and uniformly applying resin pressure to the cavity.