JPH0817187B2 - Separation mechanism of runner and IC package - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline of the Invention] A separation mechanism between a runner or gate and an IC package, more specifically, in the final step after plastic (resin) IC encapsulation, the runner or gate is formed after the IC package is molded. Regarding the mechanism for separating the IC package from the IC package, the purpose is to provide a mechanism that completely removes the resin remaining as the runner and gate from the IC package in the final step of the IC encapsulation process. As a mechanism for separating the resin adhering to the package, a rotating package guide, a linear motion runner guide,
When the projecting rod comes into contact with the runner guided by the rotating package guide, the rotating package guide rotates about the center of rotation, and the linear motion runner guide moves downward directly. The runner and the gate are separated from the IC package by applying a synthetic force of the tensile force and the shearing force to the runner and the gate.

[Industrial applications]

The present invention relates to a separation mechanism for a runner or gate and an IC package, and more specifically to a separation mechanism for separating a runner or gate from an IC package after completion of molding of the IC package in a final step after plastic (resin) IC encapsulation. It is a thing.

In recent years, automation of plastic IC encapsulation process has progressed, but in the final encapsulation separation process, there are problems such as runner remaining, gate remaining, cradle deformation, etc., and stable product quality supply is required. ing. However, currently used separation techniques have not yet solved the above problems.

[Conventional technology]

FIG. 5 is a front view of a separation mechanism of a runner and an IC package of a conventional example. In the figure, 31 is a protruding rod that transmits an external force, and 32 is left in a runner portion (may be a cull) of a cavity of a molding die. The resin is called a runner, and 33 is the resin left in the gate leading to the cavity and called a gate. In the mold, what is called a runner and a gate shows a portion where the above-mentioned resin accumulates, but in the present specification, the runner and the gate represent the resin remaining in the mold as described above, while The relevant part of the mold will be called a runner part and a gate part.

In operation, the lowering of the protruding rod 31 separates the runner 32 and the gate 33 from the cradle 36 of the lead frame forming a part of the package 34.

FIGS. 6 (a) and 6 (b) are a plan view and a front view of a conventional example mechanism. Actually, what is shown to the right of the center line C-C and to the left of the center line is symmetrical, Seen at, they are arranged vertically displaced. In the figure, the package 34 is shown with diagonal lines, and the circle seen almost at the center of the package is a trace of a protruding rod (not shown) used when the package is released from the mold.

FIG. 7 shows the main part of the IC package 34 after the molding process. In the drawing, the part with sand is the resin described above, 37 is the lead frame, and 32A and 33A are the mold dies, respectively. The positions of the runner and gate are shown. Fifth
In the device shown in the figure, the force indicated by the arrow is applied to the runner 32 by the protruding rod, whereby the runner 32 and the gate 33 are separated from the IC package 34.

[Problems to be Solved by the Invention]

When the conventional example is used, when the resin is separated, the runner 32 and the gate 33 may remain as a part of the resin until it adheres to the cradle 36 of the lead frame.
They are also called gate remnants.

In the manufacture of plastic ICs, the IC is
After resin encapsulation, the leads of the IC package (these leads were formed on the lead frame) are plated, and the leads are bent and cut at the stage called the final progress process. Is done.
Therefore, if the runners and gates remain, plating will not be applied to those parts in the plating process. Therefore, if the runners and gates remain, they must be manually separated. In addition, there are problems that the package body is cracked and the cradle 36 is deformed by the force applied when separating the gate.

When the worker presses the runner and the gate with fingers and separates the package part by bending it, the gate and the package part are separated well, and it is confirmed that the gate remains and the package body does not crack afterwards. Was done.

Therefore, the inventor of the present invention has worked on the development of a mechanism that mechanically and automatically realizes an operation similar to that of this worker manually bending and separating the gate and the package portion.

Therefore, it is an object of the present invention to provide a mechanism for completely removing the resin remaining and attached as a runner or a gate from the IC package in the final step of the IC sealing step.

[Means for solving the problem]

The above-mentioned problem is a mechanism for separating the resin adhered to the package as a runner and a gate after molding of a semiconductor package, and is provided with a rotary package guide, a direct-acting runner guide, a bias spring, and a projecting rod. When the protruding bar comes into contact with the guided runner, the rotating package guide rotates around the center of rotation, and the linear motion runner guide moves downward directly, creating a combined force of tensile force and shear force on the runner and gate. In addition, the runner and gate are separated from the IC package by that, and the runner and IC are characterized.
It is solved by the package separation mechanism.

[Action]

FIG. 1 (a) is a diagram showing the principle of the mechanism according to the present invention. Referring to FIG. 1 (a), it is caused by the rotation of the rotary package guide 11 (the center of rotation is indicated by 20) and the protrusion of the protrusion bar 15. Stable separation is performed by using the combined force of tensile force and shearing force.

Referring to FIG. 3, when a force F is applied to the runner 32 of the combination of the IC package 34, the runner 32, and the gate 33 arranged in the mechanism of the present invention, a tensile force f ₁ is applied to the gate 33.
And the shear force f ₂ work at the same time. Referring now to FIG. 1 (b), the protruding bar (which may be a long plate) exerts a force F in the direction indicated by arrow III, causing the rotating package guide 11 to rotate in the direction indicated by arrow I, The runner guide 13 linearly moves in the direction of the arrow II, so that the shearing force and the tensile force act on the gate almost at the same time. Rotating package guide 11
If the linear motion runner guide and the linear motion runner are fixed and do not move, the runner will only receive force,
When a force is applied to the runner, the rotating package guide and the linear motion runner guide move as described above, and the IC package 34 has the other cradle on the opposite side of the illustrated cradle mounted on the support shaft 16. Since the IC package bends slightly downward at the part connected to the runner, it remains almost stationary as a whole, so cracks occur at the part attached to the cradle of the gate, and at the same time the gate is seen in the figure. The gate and runner are separated from the IC package by the downward pulling force.

That is, according to the present invention, a combined force of a tensile force and a shearing force is generated between the gate and the cradle, and at that time, the rotary package guide 11 and the linear motion runner guide 13 are arranged as shown in FIG. 1 (b). Exercise, thereby separating the gate and runner from the package or cradle. Furthermore, the runner and the gate can be cooled with the cooling air supplied from the nozzle 19, so that the runner and the gate can be separated more effectively.

〔Example〕

Hereinafter, the present invention will be specifically described with reference to the illustrated embodiments.

An embodiment of the present invention is shown in the plan view of FIG. 2 (a) and the side view of FIG. 2 (b).

In the embodiment of the present invention, the rotating package guide 11 having a spread for hatching the IC package for guiding the IC package,
(The diagonal line is attached to one of the rotating packages.) Bias spring 12 for pressing rotating package guide 11 (Bias spring 12 is hidden under rotating package guide 11 so it is shown in broken lines in the figure.) The linear motion runner guide 13, the bias spring 14 for biasing the linear motion runner guide 13, the protruding bar 15 for applying an external force to the runner, the support shaft 16 for supporting (supporting) the rotating package guide, and the rotation of the rotating package guide 11 It consists of a stopper 17 that serves as a stop, and the runner guide 13 and the bias spring 14 are shown in detail in the sectional view of FIG. 2 (c). The rotating package guide 11 can rotate in the direction of arrow I in FIG. 1 (b) about the rotation center 20 shown in FIG. 2 (b). The bias spring 12 is a double torsion spring as shown in the side view and plan view of FIGS. 2 (d) and (e), which causes the rotating package guide 11 to move upwards as viewed in FIG. 2 (b). It is biased, but its upward movement is limited by the stopper 17. Inside the linear motion runner guide 13, a nozzle 19 for ejecting cooling air supplied from the outside is provided. The nozzle 19 is constituted by a hole perpendicular to the groove 19a extending in the length direction of the rotary package guide 11, as seen in the partial plan view of the rotary package guide 11 in FIG. 2 (d). In order to limit the upward movement of the linear motion runner guide 13 heated by the bias spring 14 as viewed in FIGS. Stopper at the end of cylinder 21
22 is provided, which is structured to abut the bearing 23.

When the molding shown in FIG. 4 is placed on the mechanism of FIG. 2, the ejector bar 15 is abutted on the runner. Cooling air is jetted from the nozzle 19 of the linear motion runner guide 13 to locally cool the runner and the gate. Subsequently, when the support plate 18 for supporting the entire mechanism rises in the direction of the arrow in FIG. 2 (b), the runner 32 hits the projecting rod 15 and the force F shown in FIG. 3 (b) is applied to the runner 32. A tensile force f ₁ and a shearing force f ₂ are applied to the gate 33, and the runner and the gate move as shown in the figure. At this time, the rotating package guide 11 rotates in the direction of the arrow I as shown in FIG. 1 (b) against the bias spring 12, and the linear motion runner guide 13 resists the bias spring 14 as shown in FIG. ) In the direction of arrow II,
As a result, a shearing force and a tensile force are applied to the runner 32 and the gate 33 held by the rotating package guide 11 and the linear motion runner guide, and the combined force of the tensile force and the shearing force separates the runner and the gate from the package. finish. This tensile force and shearing force are
Adjust by adjusting 12 and 12 respectively. The support plate 18 then descends in the direction of the arrow and the components of the mechanism return to the positions shown in FIG. Support plate 18 mentioned above
Instead of moving up and down, the supporting plate 18 may be fixed and the protruding bar 15 may move up and down.

The force relationship of the embodiment of the present invention described above is shown in FIG.
The figure (a) shows the initial state, and the runner 32 and the gate 33, which are shown in white, respectively, are positioned in contact with the rotary package guide 11 and the linear motion runner guide 13, which are shown by hatching.

Here, as shown in (b) of the figure, the rod protruding to the runner 32
Rotating package guide when force F is applied by 15
By the above-mentioned movement of 11 and the linear motion runner guide 13,
A tensile force indicated by f ₁ and a shearing force indicated by f ₂ in the figure act on the gate 33. If there is no loss of force F,
F = f ₁ + f ₂ . Due to the pulling force of f ₁ and the shearing force of f ₂ , the worker's finger described above is runner on the gate 33.
32, the gate 33 is pressed and the IC package 34 is separated by bending, and the gate 33 and the IC package 34 are separated from each other, which may cause a gate residue or a crack in the IC package 34. There is no. In FIG. 3 (b), the chain double-dashed line indicates the position of the runner 32 in the state of FIG. 3 (a), the arrow I indicates the rotation direction of the rotary package guide, and the broken line indicates the center line of the lead frame 37.

Runners and gates, which are unnecessary materials after the separation, are discarded by another mechanism not shown.

FIG. 4 is a plan view of the molded product, showing (a) the projection mold and (b) the multi-plunger mold. The main difference between the two is that the projection mold suitable for mass production in FIG. 3A is formed by flowing resin from the runner 32 leading to the cull (not shown) to the gate 33, while the projection mold in FIG. The multi-plunger mold shown in (1) is formed by allowing resin to flow directly from the cull 38 to the gate 33, and this mold is suitable for making a high quality IC package.

〔The invention's effect〕

As described above, according to the present invention, the combined force generated between the cradle and the runner or the gate and the local cooling of the gate and the runner enable stable separation of the runner and the gate, and a stable IC. Package production and
It is effective for improving the reliability of IC packages. The mechanism of the present invention can be applied to both the projection mold and the multi-plunger mold.

[Brief description of drawings]

FIG. 1 is a view showing the principle of the present invention, in which (a) is a front view of a mechanism according to the present invention, (b) is a front view of a gate and a runner, and FIG. 2 is a view of an embodiment of the present invention. (A) is a plan view,
(B) is a side view, (c) is a sectional view of the linear motion runner guide, (d) and (e) are side views and a plan view of the bias spring 12, and (f) is a plan view of a part of the rotating package guide. FIG. 3 is a diagram showing the force relationship of the embodiment of the present invention, in which (a)
Is an initial state, (b) is a diagram showing a state at the time of separation, FIGS. 4 (a) and (b) are plan views of a molded product, FIG. 5 is a front view of a conventional example, and FIG. 6 is a diagram of a conventional example. Here, (a) is a plan view, (b) is a front view, and FIG. 7 is a front view of a runner and a gate in a conventional example. In the figure, 11 is a rotating package guide, 12 is a bias spring, 13 is a linear motion runner guide, 14 is a bias spring, 15 is a protruding rod, 16 is a support shaft, 17 is a stopper, 18 is a support plate, 19 is a nozzle, and 19a. Is a groove, 20 is a center of rotation, 21 is a cylinder, 22 is a stopper, 23 is a bearing, 24 is a clamp, 31 is a protruding rod, 32 is a runner, 33 is a gate, 34 is an IC package, 35 is a package guide, 36 Indicates a cradle, 37 indicates a lead frame, and 38 indicates a cull.

Claims (1)

[Claims] 1. A rotating package guide (11) and a linear motion runner guide (1) having a mechanism for separating the resin adhering to the package as a runner and a gate after molding a semiconductor package.
3), the bias springs (12, 14) and the protruding bar (15) are provided, and when the protruding bar (15) comes into contact with the runner (32) guided by the rotating package guide (11), the rotating package guide is Rotating around the center of rotation (20), the linear motion runner guide (13) linearly moves downward, and the runner (32)
And the combined force of tensile force and shearing force is applied to the gate (33),
As a result, the runner (32) and the gate (33) are separated from the IC package.