JPH07266383A - Separating method of loss synthetic resin from lead frame for electronic part, and separation device using the method - Google Patents

Abstract

PURPOSE:To reduce occurrence of a cracking in a resin mold part in a lead frame, by a method wherein after the lead frame is bent in the direction of a stuck surface side of loss synthetic resin out of both front and rear surfaces of the lead frame, the lead frame is bent in its opposite direction. CONSTITUTION:The top of a resin mold part M is pressed by a pressing pin 2, through which the bottom of the resin mold part M is forced to abut against a substrate 1 so as to follow after a groove surface of the substrate 1. At that time, the lead frame L is in a bent state bending downward by taking a supporting position of the lead frame L as a fulcrum. A suction face of a suction pad is held by sucking by abutting against a cull R1, the lead frame L is conveyed to the substrate 3 in the second unit and the top of the resin mold part M is pressed by the pressing pin similarly to the first unit. The bottom of the resin mold part M is forced to abut against the substrate so as to follow after the groove surface of the substrate 1. At that time, a connecting part K becomes a condition bent upward.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for separating loss synthetic resin from a lead frame for electronic parts and a separating device using the same.

[0002]

2. Description of the Related Art Generally, molding of a resin mold portion of an electronic component such as an IC using a lead frame made of metal such as iron is performed as follows. That is, a strip-shaped lead frame is provided with a resin pot for containing a resin tablet made of epoxy resin, a runner groove connected to the resin pot and extending along the longitudinal direction of the lead frame, and a plurality of gates branched from the runner groove. The groove and the resin molding cavity that communicates with this gate groove are sandwiched between the molds engraved on the mating surface of the lead frame from above and below, and the resin heated by the resin pot is melted from the runner groove to each gate groove. The resin mold portion of each electronic component is molded so as to seal the semiconductor elements mounted at regular intervals along the longitudinal direction of the lead frame by guiding the resin through the cavity.

At the time of molding the resin mold portion, the loss synthetic resin is simultaneously molded in the resin pot, the runner groove and the gate groove, so that it is necessary to separate the loss synthetic resin from the lead frame. As shown in FIGS. 1 and 2, the loss synthetic resin is formed by connecting a cull R1 molded in a resin pot, a rod-shaped runner resin R2 molded in a runner groove, and a gate resin R3 molded in a gate groove. The gate resin R3 is attached to one side of the long side edge of the lead frame L. (In the figure, the loss synthetic resin is molded so as to spread through the runner resin R2 and the gate resin R3 to the resin mold portion M of the two lead frames L arranged in parallel on both sides of the cull R1. Therefore, conventionally, for example, it is described in FIGS. 2 and 3 of Japanese Utility Model Laid-Open No. 1-169030 or FIG. 2 of Japanese Utility Model Laid-Open No. 2-17838, and is shown in FIGS. 7 and 8. As described above, the lead frame L after molding the resin mold portion M is sandwiched between the pair of upper and lower members 21 and 22 with the loss synthetic resin R at one longitudinal edge of the lead frame L facing downward. While supporting, lead frame L
The loss synthetic resin R at one longitudinal edge of the movable member 23
Thus, as shown by arrow C, the lead frame L is separated by pushing it downward.

[0004]

However, in such a conventional separation method, the lead frame L is supported with the loss synthetic resin R at one longitudinal edge thereof facing downward, and in this state, the The loss synthetic resin R at one side edge is pushed down, and the gate synthetic resin R among the loss synthetic resin R is pushed down by pushing down the loss synthetic resin R.
Since the bending moment acts on the whole of the gate resin R3, when the bending moment acts on the whole of the gate resin R3 in the middle of the pushing down, the gate resin R3 breaks in the middle and the loss occurs. There is a problem that the synthetic resin R is left unremoved or the resin mold portion M of the lead frame L is chipped.

To solve this, Japanese Patent Laid-Open No. 4-372
In Japanese Patent Publication No. 140, as shown in FIG. 9, after molding the resin mold portion M, either one of the lead frame L and the loss synthetic resin R is supported, and the other is supported in this state. By pressing in a direction toward the surface of the front and back surfaces of L on which the gate resin R3 does not exist, D
It has been proposed that the loss synthetic resin R be separated from the lead frame L after a bending moment is intensively applied in the direction to fold the connecting portion.

However, in the above separating method, the lead frame L and the gate resin R3 in the loss synthetic resin R are used.
Since it has a strong adhesion with, it does not break the connecting part securely,
The gate resin R3 was likely to partially remain on the resin mold portion M, and the loss of the loss synthetic resin R could not be completely eliminated. The present invention has been devised under the circumstances as described above, and when the loss synthetic resin is separated from the lead frame, the resin mold portion of the lead frame is chipped or the loss synthetic resin is left behind. An object of the present invention is to provide a resin molding method for an electronic component, which can surely reduce the above-mentioned deterioration, and a runner resin separating device using the same.

[0007]

In order to solve the above-mentioned problems, according to the present invention, when a resin mold portion is molded on a lead frame for electronic parts, the resin frame is molded in a state of being attached to one longitudinal edge of the lead frame. A method for separating loss synthetic resin from the lead frame, wherein the lead frame is bent in a direction toward a surface to which the loss synthetic resin is attached on both front and back surfaces of the lead frame. It is intended to provide a method for separating loss synthetic resin from a lead frame for electronic parts, which is characterized in that it is later bent in the opposite direction.

Further, the present invention is a loss synthetic resin separating device for separating the loss synthetic resin from the lead frame by using the method according to claim 1, wherein both sides of the lead frame are covered. A support body that supports the opposite side of the one longitudinal side edge of the lead frame on one of the surfaces, and the lead frame with the support point of the lead frame supported by the support body as a fulcrum. A first unit having a pressing body that bends in the direction toward the side, a support body that supports the loss synthetic resin, and the lead frame with the loss synthetic resin supporting point of the loss synthetic resin supported by the support body. And a second unit having a pressing body that bends in the direction of the attachment surface of the loss synthetic resin.

[0009]

According to the present invention, therefore, when the resin mold portion is molded on the lead frame for electronic parts, the lead frame is attached to the front surface and the back surface of the lead frame on the side where the loss synthetic resin is attached. By bending in a direction and concentrating a bending moment in the connecting portion between the loss synthetic resin and the resin mold portion, weakening the connecting strength of the connecting portion, and then bending in a direction opposite to the direction , The connection strength of the connecting portion becomes extremely weak, and at the same time, by deforming the lead frame into an arc shape, due to the difference in shape with the loss synthetic resin having a small elastic deformation, while securely folding the connecting portion, Since the loss synthetic resin can be peeled off from the lead frame, it is possible to prevent chipping of the resin mold portion and occurrence of the loss of the loss synthetic resin.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.
The present invention is not limited to this. The lead frame L after molding the resin mold portion used in this embodiment is
As described above, the loss synthetic resin R obtained by connecting and integrating the resin pot carved in the mold, the runner groove and the gate groove (not shown) to form the cull R1, the runner resin R2, and the gate resin R3. Resin R3 in
The portion is in a state of being attached to the back surface on the opposite side of the longitudinal side edges of the two lead frames L arranged in parallel with the cull R1 as the center. (See FIGS. 1 and 2) Further, the device for separating the loss synthetic resin R from the lead frame L is
A first unit for bending the connecting portion K of the loss synthetic resin R attached to the lead frame L and the resin molded portion M downward, and a second unit for bending the connecting portion K upward.
The lead frame L includes a transport unit that transports the lead frame L from the first unit to the second unit.

As shown in FIG. 3A, the first unit is composed of two support bodies 1 made of aluminum for supporting the lower surfaces of the resin mold portions M facing each other with the cull R1 as the center, and these support bodies 1. It is composed of two columnar pressing pins 2 (pressing members) made of epoxy resin that move up and down with respect to the resin mold portion M on the body. The support 1 has a groove on the upper surface having substantially the same shape as the lower surface of the resin mold portion M, and the upper surfaces are inclined about 7 degrees in the direction in which they face each other, and the support 1 is moved up and down on the lower surface. The pneumatic cylinder S1 is connected.

The pressing pin 2 has a hemispherical tip portion, and this tip portion is located on the upper surface of the resin mold portion M on the side of the joint portion K (the joint portion K between the loss synthetic resin R and the resin mold portion M).
(The vicinity) are arranged so as to oppose each other by activating the pneumatic cylinder S2. Further, in the second unit, as shown in FIG. 3B, the support 3 is tilted in the direction in which the lower surfaces face each other by about 7 degrees, and the pressing pin 4 has a tip end portion made of resin. It is arranged so as to press the side opposite to the connecting portion K ′ (the side facing the connecting portion K) on the upper surface, and is otherwise configured similarly to the first unit. The inclination angle of the support 1 is not limited to this.

Further, the transport unit is composed of an air suction pad (not shown) connected to a link mechanism for performing a desired operation by driving a motor or the like, and the suction surface of the suction pad contacts the cull R1 in the lead frame L. The lead frame L is conveyed from the first unit to the second unit while being in contact with and adsorbed and held. In this embodiment, the first
In both the second unit and the second unit, the pressing pin 4 is pressed against the upper surface of the resin mold portion M, but the present invention is not limited to this and may be in the vicinity of the connecting portion K between the loss synthetic resin R and the resin mold portion M. For example, lead frame L, Cull R1
May be pressed.

Further, in this embodiment, the supports 1, 3 are
Is connected to the cylinder in a tilted state, but the invention is not limited to this, and as shown in FIG.
Taking the supporting body 1 in the unit as an example, two cylindrical slide shafts 5 are fixed to the lower surface of the supporting body 1, and a slide guide having long grooves 6a in which both ends of the sliding shaft 5 are arranged on both sides of the supporting body 1. 6 is freely supported and the support 1 in this state
On the other hand, it is also possible to incline the support 1 by raising the pedestals 7 having different heights on both sides and pushing up the support 1, and in this case, the support 1 in the first and second units can be inclined. 3 can be made identical in shape, and the processing cost can be reduced.

Further, the materials and shapes of the supports 1 and 3 and the pressing pins 2 and 4 in this embodiment are not limited to these. The loss synthetic resin R is separated from the lead frame L as described below by using the separating device having the above configuration. First, the lead frame L in which the resin mold portion M is molded by a molding die (not shown) is mounted on the support 1 in the first unit while the cull R1 is suction-held by a suction pad or the like. Next, the resin mold part M
By pressing the upper surface with the pressing pin 2, the lower surface of the resin mold portion M is brought into contact with the groove surface of the support 1 so as to follow the groove surface. At this time, as shown in FIG.
Is bent downward with the supporting point of the lead frame L supported by the support 1 as a fulcrum, and the bending moment concentrates on the joint K between the resin mold portion M and the loss synthetic resin R. The connection strength becomes weak. After that, the suction surface of the suction pad is brought into contact with the cull R1 and suction-held, and the lead frame L is held by the support member 3 in the second unit.
It is transported to the upper part and, like the first unit, the resin mold part M
By pressing the upper surface with the pressing pin 3, the lower surface of the resin mold portion M is brought into contact so as to follow the groove surface of the support 1. At this time, as shown in FIG. 6, the connecting portion K is bent upward, and the connecting strength of the connecting portion K becomes extremely weak. The loss synthetic resin R can be peeled off from the lead frame L while the connecting portion K is reliably folded due to the difference in material from the loss synthetic resin R which is small in deformation, so that the resin mold portion M is chipped or loss is synthesized. It is possible to prevent the residual resin R from remaining.

When the connecting portion K of the lead frame L is first bent by the second unit, the connecting portion K is bent while the connecting strength of the connecting portion K remains strong. The portion K does not break, and the gate resin R3 easily breaks in the middle. In this way, loss synthetic resin R
The lead frame L separated from the above is transferred to a transfer line in the next step by a transfer means such as an air suction pad. At the time of this conveyance, the cull R1 is simultaneously adsorbed and held and transferred, and during the transfer to the next step, only the cull R1 is adsorbed and released, and the loss synthetic resin R is dropped and eliminated.

In the present embodiment, the case where the loss synthetic resin is attached to the back surface of the lead frame has been described, but the present invention is not limited to this, and the case where the loss synthetic resin is attached to the surface of the lead frame is the lead frame or The separation device may be inverted. Further, although the pressing pins 2 and 4 are pressed against the surface of the resin mold M in the present embodiment, the present invention is not limited to this, and the resin mold part M or the lead frame L is clamped by the clamper, It is also possible to weaken the connecting strength of the connecting portion K by reciprocally rotating around the connecting portion K with respect to the cull R1.

[Brief description of drawings]

FIG. 1 is a plan view of an essential part showing a lead frame for an electronic component in which a resin mold part is molded.

FIG. 2 is a cross-sectional view of an essential part showing a lead frame for an electronic component in which a resin mold part is molded.

FIG. 3 is a side view of essential parts showing an apparatus for separating loss synthetic resin from the electronic component lead frame of the present invention.

FIG. 4 is a perspective view of essential parts showing a modified example of the device for separating loss synthetic resin from the electronic component lead frame of the present invention.

FIG. 5 is an explanatory view for explaining a manner of separating loss synthetic resin from a lead frame by using the separating device of the present invention.

FIG. 6 is an explanatory view for explaining how the loss synthetic resin is separated from the lead frame by using the separation device of the present invention.

FIG. 7 is an explanatory diagram illustrating a conventional method for separating loss synthetic resin from a lead frame for electronic components.

FIG. 8 is an explanatory diagram illustrating a conventional method for separating loss synthetic resin from an electronic component lead frame.

FIG. 9 is an explanatory diagram illustrating another conventional method for separating loss synthetic resin from a lead frame for electronic components.

[Explanation of symbols]

 R Loss synthetic resin R1 Cull R2 Runner resin R3 Gate resin M Resin mold part K Connecting part 1 Support 2 Push pin 3 Support 4 Push pin 5 Slide shaft 6 Slide guide 7 Stand

Claims (2)

[Claims] 1. A loss synthetic resin for separating a loss synthetic resin formed in a state of adhering to a longitudinal one side edge of the lead frame from the lead frame when forming a resin mold portion on an electronic component lead frame. A method for separating electronic parts, characterized in that the lead frame is bent in a direction toward an adhesion surface side of the loss synthetic resin of both front and back surfaces of the lead frame and then in an opposite direction. A method of separating loss synthetic resin from the lead frame. 2. A loss synthetic resin separating device for separating the loss synthetic resin from the lead frame by using the method according to claim 1, wherein either one of front and back surfaces of the lead frame is provided. Of the lead frame on the side opposite to the one side edge, and the lead frame is bent in the direction toward the loss synthetic resin adhering surface side with the supporting point of the lead frame by the support as a fulcrum. A first unit having a pressing body, a support for supporting the loss synthetic resin, and a lead frame to the side where the loss synthetic resin is attached, with a supporting point of the loss synthetic resin by the support as a fulcrum. A loss synthetic resin separating device including a second unit having a pressing body that bends in a direction.