JPH084267Y2 - Mold for element package molding - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a mold for molding an element package on a lead frame, and particularly for detecting an abnormal arrangement of the lead frame in the mold. Regarding the improvement of.

"Prior art" When forming a resin package on the lead frame,
Description will be given by taking as an example a transfer molding die that has been frequently used.

This type of transfer mold is an upper chase (upper mold)
On the opposite surface of the lower chase (lower die), cavities each having a shape of a resin package to be formed on the lead frame are defined, and a plurality of pots communicating with each of these cavities via a gate are formed. Transfers that move up and down in these pots are provided.

When using, the lead frame is positioned and placed on the lower chase by a robot, etc., and each pot is loaded with a resin tablet to heat and soften it, the upper and lower chase are closed, and the resin is transferred through the gate to the cavity. Extrude in to form the package.

"Problems to be solved by the device" However, in the conventional element package molding die, if there is some error in the mounting position of the lead frame on the lower chase, package molding failure will occur and yield will deteriorate. Or in some cases expensive molds are damaged,
There was a possibility of receiving a great deal of damage.

Incidentally, such a problem is also applicable to an injection molding apparatus or the like which similarly forms an element package on a lead frame.

"Means for solving the problem" The present invention has been made to solve the above problems,
The element package molding die according to claim 1, wherein a package-shaped cavity to be formed on a lead frame is defined between an upper mold and a lower mold that are opened and closed, and a lead is fixed at a fixed position of the lower mold. In the element package molding die for mounting the frame and closing the mold, and injecting the molten resin into each cavity to mold the element package, the upper die and the lower die have a position opposite to the lead frame,
A detection mechanism for detecting the presence or absence of a lead frame is provided, and the detection mechanism is arranged such that the optical axes of the lead frame are aligned with each other at positions facing each other with the lead frame sandwiched between them when the mold is closed. An optical fiber embedded in
A technique including a light emitting element connected to one optical fiber and a light receiving element connected to the other optical fiber is adopted.

In the element package molding die according to claim 2, a package-shaped cavity to be formed on the lead frame is defined between an upper mold and a lower mold that are opened and closed.
After the lead frame is placed at a fixed position of the lower mold and the mold is closed, in a device package molding die for molding a device package by injecting a molten resin into each cavity, in the upper mold or the lower mold, A detection mechanism for detecting the presence / absence of a lead frame is provided at a position facing the lead frame,
The detection mechanism is an optical fiber having a tip disposed at a position facing the lead frame when the mold is closed and embedded in the upper mold or the lower mold, and an incident optical waveguide that is connected to the other end of the optical fiber and is guided into the mold. A light-emitting element that emits light, and a mold that is arranged between the light-emitting element and the optical fiber, passes the incident light, guides it to the other end of the optical fiber, and emits the light from the other end of the optical fiber. A half mirror that reflects the return light from
A technique including a light receiving element that receives the return light reflected by the half mirror is adopted.

[Operation] In this device package molding die, it is possible to directly detect whether or not the lead frame is in a fixed position by the detection mechanism provided in the upper die and / or the lower die. It is possible to prevent inconveniences such as the abnormal molding of the package and the damage of the mold.

Further, since the optical fiber embedded in the upper mold and the lower mold, and the light emitting element and the light receiving element are used as the detection mechanism, the light receiving element and the light emitting element which are vulnerable to temperature and shock are removed from the mold opening / closing surface which is easily subjected to shock at high temperature. In addition to being retracted, the placement of the lead frame can be clearly confirmed by blocking or transmitting light, which is extremely reliable.

In addition, the optical fiber can be easily fixed simply by forming holes in each mold, it does not interfere with the drive mechanism inside the mold, it does not affect the operation of the mold, and the light emitting and receiving areas are small, so the resolution is high. However, there is an advantage that even a slight position error can be clearly detected.

Further, when an optical fiber embedded in the upper mold or the lower mold and a light emitting element and a light receiving element connected to the optical fiber via a half mirror are used, incident light emitted from the light emitting element passes through the half mirror. Then, the light is incident on the other end of the optical fiber, guided through the optical fiber, and emitted from the tip thereof into the mold. Then, the return light reflected in the mold enters again from the tip of the optical fiber and is guided to the other end.
The guided light is emitted from the other end of the optical fiber to the half mirror, and is reflected by the half mirror to change its optical path, and is incident on the light receiving element.

At this time, when the lead frame is placed at a fixed position, the light becomes the return light reflected by the lead frame, and when the lead frame is displaced and does not exist at the light projection position,
The light becomes the return light reflected by the mold. Therefore, whether or not the lead frame is placed at a fixed position depends on the difference in the amount of return light between when the lead frame is reflected and returned and when it is reflected and returned to the mold, that is, the light is incident on the light receiving element. It is judged by the difference in the amount of light.

[Embodiment] FIGS. 1 and 2 show a transfer molding die of an element package according to an embodiment of the present invention. FIG. 1 is a front sectional view and FIG. 2 is a plan view of a lower chase. is there.

In the figure, reference numeral 1 is a lower surface plate fixed on a bolster (not shown) of the molding machine, 2 is a lower chase (lower mold) fixed on the lower surface plate 1, and an upper mounting plate of the molding machine facing these. (Not shown), the upper chase (upper mold) through the upper surface plate 3
4 is fixed.

On the opposing surfaces of the lower chase 2 and the upper chase 4, a pair of elongated rectangular frame recesses 5 (= fixed positions) into which the lead frame L fits are formed in parallel with each other at intervals. A recess (6) having the shape of an element package is formed side by side. Then, the lead frame L is housed in each frame recess 5 and each chase 2,
When the mold 4 is closed, the recess (6) defines the cavity 6.

As shown in FIG. 2, circular hole-shaped pots 7 into which resin tablets are inserted are formed at equal intervals between the frame recesses 5 of the lower chase 2, and each of the pots 7 has four adjacent cavities 6. A gate (not shown) that communicates with is formed. Inside each pot 7, a transfer 8 that moves up and down in conjunction with the opening and closing of the mold is arranged. When the resin tablet in each pot 7 is melted and the transfer 8 is raised, the molten resin is transferred to each cavity 6 through the gate. Injected.

Each chase 2, 4 is also formed with a fiber insertion hole 9 which is coaxial with each other vertically at one end corner of each frame recess 5 on the side far from the pot 7, and an optical fiber coating tube 10 is provided in each of these insertion holes 9. The optical axes of the optical fibers in the optical fiber cladding tube 10 that are inserted and fixed and are opposed to each other have their optical axes aligned with each other. The buried position of the optical fiber coating tube 10 is preferably closer to the top of the lead frame L because the resolution for detecting the position error is improved. In addition, the tip of each optical fiber is set to be flush with the bottom surface of the frame concave portion 5 or at a position slightly retracted for protection, and when retracted, the tip of each fiber is covered with a protective transparent plate. Good.

The other end of each optical fiber coating tube 10 is extended to the outside of the mold, and a light emitting element 11 is provided at the end of the optical fiber coating tube 10 in the upper chase 3 and an optical fiber coating tube 10 in the lower chase 2 is provided. The light receiving elements 12 are connected to the end portions of each.

Light emitting diodes, various light bulbs, and the like are suitable as the light emitting element 11, and CdS cells, phototransistors, photodiodes, and the like can be used as the light receiving element 12. The light emitting element 11 and the light receiving element 12 are both connected to a mold control board, and an alarm device or the like is activated in response to the signal.

Next, a method of using this transfer molding die will be described. The light emitting element 11 is always energized and emits light.

First, in the mold open state, a resin tablet is loaded into each pot 7 of the lower chase 2 and the lead frame L is housed in each frame recess 5 by a robot or the like. Next, the light receiving element 12
From the light emitting element 11 is blocked by the end portion of the lead frame L and the light receiving element 12 does not detect light.
The mold is closed as usual, the transfer 8 is raised, and the molten resin is injected into each cavity 6.

However, in the unlikely event that the light receiving element 12 is in the light receiving state,
The mold closing is stopped and an alarm is sounded, or the lead frame L on the lower chase 2 is automatically removed by a robot or the like, and the lead frame L is set again from the beginning.

On the other hand, after the molding is completed, the lead frame L on which the mold is opened and the package is formed is conveyed to the next step by a robot or the like, and at the same time, it is confirmed that the signal from the light receiving element 12 is in the light receiving state. If it is in the cutoff state, the supply of the next lead frame is stopped and an alarm is sounded.

As described above, according to this transfer mold, it is possible to directly detect whether or not the lead frame L is accurately accommodated in the frame recess 5, and thus the molding error of the package due to an arrangement error, the mold damage, or the like. Inconvenience can be prevented, productivity can be improved, and cost can be reduced.

Further, since the optical fiber 10 and the light emitting element 11 and the light receiving element 12 are used as the detection mechanism, these elements 11 and 12 which are vulnerable to temperature and shock are retracted from the respective molds 2 and 4 which are susceptible to shock at high temperature. It is possible to reduce cost by using expensive heat-resistant and impact-resistant elements, and to block light.
Since the arrangement of the lead frame can be clearly confirmed by transmission, the reliability is extremely high.

Further, the optical fiber coating tube 10 can be easily attached only by forming the insertion holes 9 in the molds 2 and 4, does not interfere with other driving mechanisms in the mold, does not affect the operation of the mold, and emits light. Further, since the light receiving area is small, the resolution is high, and even a slight position error of the lead frame can be clearly detected.

Further, in this example, since the optical fiber coating tube 10 is embedded in the corner of the frame recess 5, it is easy to detect an abnormality even if the lead frame L is displaced in either the longitudinal direction or the width direction.

The embedding position of each optical fiber coating tube 10 may be appropriately changed according to the shape of the lead frame L. In this case, the embedded position of the lead frame L is set so that an abnormality can be easily detected even if the lead frame L is displaced in any direction.
It is desirable that the periphery should face the portion surrounded by the opening as much as possible. If necessary, a position detecting portion satisfying such a condition may be formed in advance on the lead frame L.

Further, although one detection mechanism is provided for each lead frame L in the above embodiment, the number of the detection mechanisms may be two or more to further improve the positional deviation detection accuracy.

Further, the light emitting element 11 may not be always turned on as described above, but may be turned on only at the time of detection, and a condenser lens may be attached to the optical fiber coating tube 10 on the light receiving side.

Further, in the above-mentioned embodiment, the lead frame L is detected by blocking the optical path, but instead, an optical path separator using a half mirror is connected to the optical fiber, and the light from the light emitting element is passed through the optical path separator. The lead frame may be irradiated with the light, and the reflected light from the lead frame may be received again by the same optical fiber, the optical path may be changed by the optical path separator, and the reflected light may be detected by the light receiving element. The half mirror allows the light emitted from the light emitting element to enter the optical fiber from the other end without changing the optical path and reflects the return light from the mold emitted from the other end of the optical fiber to reflect the light. Is arranged at a position where the optical path of is changed and is incident on the light receiving element. In this case, whether or not the lead frame is placed at a fixed position is determined by the difference in the amount of return light between when the lead frame reflects and returns and when the lead frame reflects and returns. It is determined by the difference in the amount of light emitted. In this case, it is sufficient to embed the optical fiber only in one chase, and the degree of freedom in construction is increased.

Further, the present invention can detect the lead frame by using various contact sensors, electromagnetic sensors, inductance sensors, capacitance sensors, etc., in addition to the detection by the optical element as described above.

Further, the present invention is not limited to the transfer molding die described above, and can be applied to a case where an element package is molded by an injection molding device or another type of molding device.

[Advantage of Invention] As described above, according to the die for molding the element package of the present invention, whether the lead frame is in a fixed position or not can be directly detected by the detection mechanism provided in the upper die and / or the lower die. Since it is possible to detect it, it is possible to prevent inconveniences such as abnormal molding of the package and damage to the mold due to the placement error of the lead frame.

Further, when the optical fiber embedded in the upper mold and the lower mold, and the light emitting element and the light receiving element are used as the detection mechanism, the light receiving element and the light emitting element, which are weak against temperature and shock,
In addition to being able to evacuate from the mold opening and closing surface, which is susceptible to shocks at high temperatures, it is possible to reduce cost by not using expensive heat and shock resistant elements, and to clearly arrange the lead frame by blocking and transmitting light. The signal processing is easy and the reliability is extremely high.

Furthermore, the optical fiber can be easily fixed by simply forming holes in each mold, it does not interfere with the drive mechanism inside the mold, it does not affect the mold operation, and the light emitting and receiving areas are small, so the resolution is high. However, there is an advantage that even a slight position error can be clearly detected.

Then, an optical fiber embedded in the upper mold or the lower mold, a light emitting element connected to the other end of the optical fiber, a half mirror arranged between the light emitting element and the optical fiber, and the half mirror. When using a light receiving element that receives the reflected return light, whether or not the lead frame is placed at a fixed position depends on whether the lead frame is reflected back to the lead frame or returned to the mold. Since the judgment is made based on the difference in the amount of return light from that when the mold is opened, it suffices to embed the optical fiber in only one mold, increasing the degree of freedom in the configuration and reducing the mold work. .

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a device package molding die according to the present invention, and FIG. 2 is a plan view of a lower chase in the same device. L: Lead frame, 2 ... Lower chase (lower mold), 4
...... Upper chase (upper mold), 5 ... Frame recess (fixed position), 6 ... Cavity, 7 ... Pot, 8 ... Transfer, 9 ... Fiber insertion hole, 10 ... Optical fiber cladding tube, 11 …… Light emitting element, 12 …… Light receiving element.

Claims (2)

[Scope of utility model registration request] 1. A package-shaped cavity to be formed on a lead frame is defined between an upper die and a lower die that are opened and closed, and the lead frame is placed at a fixed position of the lower die to close the die. In addition, in the element package molding die for molding the element package by injecting the molten resin into each cavity, the upper die and the lower die detect the presence or absence of the lead frame at the position facing the lead frame. A mechanism is provided, and the detection mechanism includes an optical fiber embedded in each of the upper mold and the lower mold, the optical axes of which are aligned with each other so that their optical axes coincide with each other at positions facing each other across the lead frame when the mold is closed. An element package molding die, comprising a light emitting element connected to one optical fiber and a light receiving element connected to the other optical fiber. 2. A package-shaped cavity to be formed on a lead frame is defined between an upper mold and a lower mold that are opened and closed, and the lead frame is placed at a fixed position of the lower mold to close the mold. In addition, in the element package molding die for injecting the molten resin into each cavity to mold the element package, the upper die or the lower die has a detection position for detecting the presence or absence of the lead frame at a position facing the lead frame. A mechanism is provided, and the detecting mechanism is connected to the optical fiber having the tip located at a position facing the lead frame when the mold is closed and embedded in the upper mold or the lower mold, and is guided to the inside of the mold by being connected to the other end of the optical fiber. A light emitting element that emits the incident light that is radiated, and is disposed between the light emitting element and the optical fiber to pass the incident light and guide it to the other end of the optical fiber, and to output from the other end of the optical fiber. An element package molding die, comprising: a half mirror that reflects the returning light from the inside of the die that is projected, and a light receiving element that receives the returning light reflected by the half mirror.