JPH0845975A - Resin molding die for semiconductor element - Google Patents

Abstract

PURPOSE:To remove resin flash from a lead frame by moving a resin flash removing unit and a resin flash receiver up and down independently from a die itself upon finishing the packaging. CONSTITUTION:A moving system 16 is interlocked with a cylinder rod 12a to ascend thus pushing up a resin flash removing unit 4. The resin flash removing unit 4 pushes up, at the forward end, resin flashes 3 in a region surrounded by an opposing dam bar 1a, a lead 1b, and a package 1. Consequently, the resin flashes 3 are removed from the region and pushed into a through hole inserted with the resin flash receiver 5 of upper die. The resin flash receiver 5 is pushed up as the resin flash removing unit 4 ascends and the removing unit 4 is inserted into the through hole upon finishing removal of resin flash. This structure eliminates the need of additional step for removing the resin flash and the resin flash, causing trouble in the subsequent steps, can be removed prior to the cutting step.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for resin-sealing a semiconductor.

[0002]

2. Description of the Related Art FIG. 4 is a schematic plan view showing a semiconductor device after resin sealing. The package 2 is formed by sealing the periphery of a semiconductor element, which is die-bonded on the die island of the lead frame 1 and electrically connected to the internal lead by wire bonding, with a resin. At this time, as indicated by reference numeral 3, a resin burr 3 is generated in a region surrounded by the dam bar 1a, the lead 1b and the package 2 of the lead frame 1.

The resin burr 3 is a drop-off burr that occurs due to the abutting gap between the upper mold and the lower mold of the resin-sealed mold, and if left unattended, it will fall off in a later step, which not only adversely affects the apparatus. Various problems such as deterioration of dimensional accuracy and quality of products occur. Therefore, a process for removing the resin burr 3 is required. However, since the resin burr 3 is a relatively thick one having a thickness of about the lead frame, it is generally punched by a dedicated punch or tie bar cut at the same time. Remove by punching with a cutting die.

[0004]

As described above, when the resin burr is punched out by the dedicated punch, a dedicated mold is prepared,
Since a process for punching resin burrs was added, the cost increased. When punching out resin burrs with a cutting die (tie cutter), the resin is extremely hard and the cutting die is heavily worn, and it takes a lot of time to replace the cutting die. The resin burr remains on the lead frame due to the abrasion of the resin, and the resin burr drops off during lead cutting and lead bending, which are the later processing steps, and adversely affects the package. There has been a problem that cracks, chips, etc. occur, leading to deterioration in quality. To cope with this, the process procedure is changed and a resin burr removing process is provided before solder plating to remove residual resin burr by cleaning before plating, but the cost is increased.

For this reason, the lead frame has a shape in which a convex portion is provided on the dam bar, and a dam bar capable of resin burr,
There is a method in which a region surrounded by leads and a package is almost filled with the convex portion so that the resin does not flow into the region at the time of resin sealing. However, this method cannot be used when resin burrs must be generated as a measure against misalignment, voids, and unfilling in the mold due to the tolerance of the lead frame. In addition, in order to reduce the resin burr to the extent that it does not have to be removed later, the gap between the convex portion and the package formation planned area (cavity) must be made extremely narrow, which is highly accurate during resin sealing. Since positioning is required,
The processing accuracy of the lead frame and the mold had to be increased, which led to an increase in production cost.

[0006]

In order to solve the above problems, the present invention provides a resin deburring device consisting of a pin in a through hole provided in one of the upper mold and the lower mold of a resin sealing mold. Insert the resin burr receiver consisting of a pin through the through hole provided in the other split mold, and dispose the tip of the resin burr remover and the tip of the resin burr receiver opposite to each other through the resin burr formation planned region, An actuator for moving the resin burr remover up and down is attached to the split mold in which the resin burr remover is inserted, and a spring for applying a biasing force to the resin burr receiver in the direction of the resin burr remover is inserted through the resin burr receiver. Attached to the divided mold, and after the resin sealing is completed, the tip of the resin burr remover protrudes out of the mold through which the resin burr remover is inserted and pushes the resin burr at the same time. Fat burr receiving tip is pushed through the resin burr at the tip off the resin burr, the tip off the resin burr, characterized in that it is inserted into the hole which is inserted through the receiving the resin burr.

Further, in a resin-sealing mold for resin-sealing a semiconductor element fixed to a lead frame, a resin burr remover consisting of a pin is inserted into a through hole provided in one of the upper mold and the lower mold. Then, the resin burr receiver made of a pin is inserted into the through hole provided in the other split mold, and the tip of the resin burr remover and the tip of the resin burr receiver are arranged so as to face each other through the resin burr formation planned region. A first actuator for moving the resin burr remover up and down is attached to the split mold through which the resin burr remover is inserted, and a second actuator for vertically moving the resin burr receiver corresponding to the movement of the resin burr remover is provided. If the tip of the resin burr remover is attached to the split mold through which the resin burr receiver is inserted and the mold is clamped after the completion of the resin sealing, the resin burr remover protrudes out of the inserted mold. The resin burr is pushed and split, and at the same time, the resin burr receiving tip is drawn into the split mold through which the resin burr receiving is inserted, and the resin burr removing tip is inserted into the through hole through which the resin burr receiving is inserted. It is characterized by

[0008]

With this configuration, the resin burr remover and the resin burr receiver, which operate separately from the movement of the mold itself after the formation of the package, moves up and down, and leads the resin burr existing at the tips of both. Exclude from the frame.

1 to 3 are schematic sectional views showing an embodiment of the present invention in the order of operation. 1 is a mold before mold clamping (clamp open), FIG. 2 is a mold when resin is filled in the cavity after mold clamping (clamp), and FIG. 3 is resin deburring and resin immediately after completion of resin sealing. The molds when the burr receiver operates are shown below. In these figures, the same parts are designated by the same reference numerals, and the same reference numerals as those in FIG. 4 indicate the same or corresponding ones.

Embodiments of the present invention will be described below with reference to the drawings. Reference numeral 1c indicates a semiconductor element, which is fixed and wired on the lead frame 1. Reference numerals 4 and 5 denote a resin burr remover and a resin burr receiver, respectively, which are the same as ejector pins used in general molds, and whose tips are surrounded by the dam bar 1a and the lead 1b of the lead frame 1 and the package 2. (See FIG. 4). Ejector pin plates 6 and 7 fix the resin burr remover 4 and the resin burr receiver 5 by sandwiching the heads 4a and 5a together with the retainer plates 8 and 9. Reference numerals 10 and 11 denote return pins, which mainly guide the vertical movement of the ejector pin plates 6 and 7 and the retainer plates 8 and 9. Reference numeral 12 denotes an actuator such as a hydraulic cylinder, and its cylinder rod 12a is connected to the retainer plate 8. Reference numeral 13 denotes a tension spring, which is arranged in the gap between the ejector pin plate 7 and the upper mold 15. In addition, runners, culls, pots, plungers, and the like, which are omitted in the drawing, are the same as in the related art.

As shown in FIG. 1, a tension spring 13 is arranged between the upper die 15 and the ejector pin plate 7, and one end of the tension spring 13 is fixed to the upper die and the other end is fixed to the ejector pin plate 7. Therefore, when the clamp is opened, the resin burr receiver 5 is urged by the urging force of the tension spring 13.
The moving system 17 including the ejector pin plate 7 and the retainer plate 9 is pushed downward, and the tip end surface of the resin burr receiver is positioned substantially flush with the abutment surface of the upper die 15 with the lead frame 1.

On the other hand, the moving system 16 including the lower resin burr remover 4, the ejector pin plate 6, and the retainer plate 8 is a cylinder rod 12a of the actuator 12.
When the clamp is opened, the cylinder rod 12a is pulled into the actuator 12 by a command from the control system (not shown) to the actuator 12, and the tip surface of the resin deburring unit 4 is the lead of the lower mold 14. It is positioned so as to be substantially flush with the abutment surface with the frame 1. Although not shown, a through hole communicates with the center of the ejector pin plate 7, the retainer plate 9, and the mounting plate 19, and a pot (not shown) is inserted into the through hole.

At the time of clamping, the lower mold 14 is raised by the operation of an actuator of a press machine (not shown) and collides with the upper mold 15, after which resin is injected and the cavity is filled with the resin, and the package 1 as shown in FIG. Is formed. After curing for a predetermined time, the actuator 12 is operated by a control system (not shown) while the clamp is being performed, and the cylinder rod 12a is projected. The moving system 16 rises in conjunction with the cylinder rod 12a, and the resin burr remover 4 is pushed up. At this time, the resin burr 3 in the area surrounded by the dam bar 1a, the lead 1b, and the package 1 where the tip of the resin burr remover 4 faces is pushed up, the resin burr 3 is removed from the area, and the resin burr receiver 5 of the upper die is removed. It is pushed into the inserted through hole. The resin burr receiver 5 is pushed up as the resin burr remover 4 rises, and when the resin burr removal is completed, the resin burr receiver 4 is inserted into the through hole through which the resin burr receiver 5 is inserted (FIG. 3).

Thereafter, the lower die 14 is lowered by the operation of the actuator (not shown), and at the same time, the actuator 12 is activated to pull in the cylinder rod 12a and pull the resin burr remover 4 into the lower die 14. The moving system 17 is pushed downward by the urging force of the spring, and the resin burr receiver 5
Is pushed down, the resin burr 3 is discharged to the outside of the upper mold 15. Thereafter, the resin burr 3 is removed from the mold by air blow or the like. The lead frame 1 and the lower die 14 are separated from each other by lowering the lower die 14 in the same manner as in the conventional case.
1 by pushing the retainer plate 22 and causing the ejector pin 20 to project.

As a result, the effect is that the resin burr which is a problem in the subsequent process can be removed to some extent, and a slight amount of the remaining burr can be removed by the cleaning before plating in the next process. Therefore, it is possible to eliminate the problem of resin burr driving in the cutting process. Although the lower mold is the movable mold and the upper mold is the fixed mold in the above-mentioned embodiment, it is needless to say that the invention can be applied to the opposite case. Also,
In the above embodiment, the resin burr receiver is moved up and down by a biasing force of a tension spring provided between the resin burr receiver and the upper die, and the resin burr receiver is moved up and down in response to the up and down movement of the resin burr. However, the same can be done by using an actuator such as a hydraulic cylinder or a solenoid instead of a spring. At this time, the actuator used can be controlled by the same control system as other actuators.

[0015]

As described above, by adding the resin deburring function to the resin sealing mold, the resin deburring step is not added, and the resin deburring which becomes a problem in the subsequent steps is cut before the cutting step. Can be removed and stable and high quality products can be secured.

Further, since the resin burrs are cut by inserting the pins into the area surrounded by the dam bar of the lead frame and the leads and the package while the mold is clamped, the resin burrs can be removed and the mold dies are misaligned. You can judge the mismatch.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a clamp open state according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing the completion of resin filling according to the embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view showing the time of removing resin burr according to the embodiment of the invention.

FIG. 4 is a diagram showing a resin burr generated between the dam bar, the lead, and the package after resin sealing.

[Explanation of symbols]

 1. Lead frame 1a. Dam bar 1b. Lead 1c. Semiconductor element 2. Package 3. Resin burr 4. Resin deburring 4a, 5a. Head 5. Resin burr receiver 6,7. Ejector pin plate 8, 9. Retainer plate 10, 11. Return pin 12. Actuator 12a. Cylinder rod 13. Extension spring 14. Lower mold 15. Upper mold 16, 17. Mobile system 18, 19. Mounting plate 20. Ejector pin 21. Ejector rod 22. Retainer plate

Claims (2)

[Claims] 1. A resin encapsulation mold for encapsulating a semiconductor element fixed to a lead frame with a resin, wherein a resin burr remover consisting of a pin is inserted into a through hole provided in either one of the upper mold and the lower mold. Then, the resin burr receiver made of a pin is inserted into the through hole provided in the other split mold, and the tip of the resin burr remover and the tip of the resin burr receiver are arranged so as to face each other through the resin burr formation planned region. An actuator for moving the resin burr remover up and down is attached to the split mold in which the resin burr remover is inserted, and a spring for giving an urging force in the direction of the resin burr remover facing the resin burr receiver is inserted in the resin burr receiver. Attached to the split mold, and in the state where the mold is clamped after the package is formed, the tip of the resin burr remover projects outside the mold through which the resin burr remover is inserted, and the resin burr is split. At the same time, the resin burr receiving tip is pushed by the resin burr removing tip through the resin burr, and the resin burr removing tip is inserted into the through hole through which the resin burr receiver is inserted. Resin sealing mold. 2. A resin encapsulation mold for encapsulating a semiconductor element fixed to a lead frame with a resin, wherein a resin burr remover made of a pin is inserted into a through hole provided in either one of the upper mold and the lower mold. Then, the resin burr receiver made of a pin is inserted into the through hole provided in the other split mold, and the tip of the resin burr remover and the tip of the resin burr receiver are arranged so as to face each other through the resin burr formation planned region. A first actuator for moving the resin burr remover up and down is attached to the split mold through which the resin burr remover is inserted, and a second actuator for vertically moving the resin burr receiver corresponding to the movement of the resin burr remover is provided. It is attached to a split mold with a resin burr receiver inserted, and the tip of the resin burr remover projects outside the mold through which the resin burr remover is inserted in a state where the mold is clamped after the package is formed. The resin burr is pushed into the mold, and at the same time, the resin burr receiving tip is drawn into the split mold through which the resin burr receiving is inserted, and the resin burr removing tip is inserted into the through hole through which the resin burr receiving is inserted. A resin encapsulating mold for a semiconductor, which is characterized by: