JP2001313360A - Jig for cutting tie bar of semiconductor ic, and method for cutting the tie bar - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove dam burrs effectively without leaving angular burrs, while prolonging the lifetime of a tool, at the time of cutting a tie bar provided on the outside of the package of a semiconductor IC. SOLUTION: The jig for cutting a tie bar comprises a punch 7 and a die 8, where a part 7a for cutting the tie bar is formed on the bottom part of the punch 7 and a burr-pressing part 7b is formed by projecting a part closer to a package 1 than the tie bar cutting part 7a downward. The die 8 has a part 8a being fitted with the tie bar cutting part 7a, and that part 8a is set back from the bur pressing part 7b in the direction receding from the package 1 side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tie bar cutting jig for cutting a tie bar provided outside a semiconductor IC package, and a tie bar cutting method using the jig.

[0002]

2. Description of the Related Art Generally, a semiconductor IC assembling process includes a molding process and a lead processing process.
In the above-described lead processing step, cutting of unnecessary portions of the lead frame after resin molding, bending of leads, and the like are performed. In particular, the lead frame is provided with a tie bar for connecting the leads in advance in order to prevent deformation of the inner lead and leakage of the mode resin during sealing.
The tie bar is unnecessary after the IC chip is resin-molded, and since each lead is individually separated, the tie bar is finally cut (tie bar cut).
Need to be separated.

FIG. 7 shows a semiconductor IC immediately before a tie bar cut.
In the figure, 1 is a package in resin mode, 2 is a lead, 3 is a tie bar, and 4 is a package 1.
It is a dam that protrudes around the area around Reed 2. This dam burr is made of the same material as the mold resin of the IC chip (for example, epoxy resin and glass filler).

FIGS. 8 and 9 show a tie bar cutting jig 1.
The state at the time of performing a tie bar cut using 0 is shown. The conventional tie bar cutting jig 10 includes a substantially rectangular parallelepiped punch 11 and a die 12 having a gap into which the punch 11 is fitted. Both of the punches 11 and 12 have the same size along the longitudinal direction of the lead 2. And has a predetermined length from the position of the dam beam 4 close to the package 1 to the outside of the tie bar 3, and the width of the punch 11 is
Are set so as to be slightly narrower than the opposing interval of. The reason for this is to prevent the seizure or deformation of the lead 2 by the punch 11 during tie-bar cutting, because the opposing distance between the adjacent leads 2 slightly varies from one lead to another. As an example, the distance Δ from the lead 2 to the punch 11 is about 50 μm.
Then, the tie bar 3 and the dam burrs 4 are cut and removed at the same time as the punch 11 descends and fits into the gap between the dies 12.

[0005]

As described above, in the tie bar cutting jig 10, the width of the punch 11 is slightly smaller than the interval between the leads 2 in order to prevent the leads 2 from galling and deformation. Because it needs to be set,
After the tie bar cut, a dam beam 4 as shown in FIG.
The remaining parts 4a and 4b exist. Especially Lead 2
The left and right horn-shaped remaining portions 4a extending to the portion where the tie bar 3 was along along the line are hereinafter referred to as corners.

As described above, the conventional tie bar cutting jig 1
When 0 is used, the corner 4a remains after cutting, and if the semiconductor IC is transferred to the subsequent bending process of the lead 2 in that state, the following inconvenience occurs. That is, since the lead 2 is bent at a portion close to the remaining portion of the corner 4a, the corner 4a is deformed in the pulling direction at the upper portion and in the compression direction at the lower portion. , The corner 4a is peeled off from the lead 2,
The peeled-off scatters on packages, leads, processing tools, devices, and the like, and causes various problems. For example, when performing various tests, when the scattered burrs adhere to the leads 2 and intervene between the contact pins (not shown) of the IC socket, poor contact between the leads 2 and the contact pins occurs, and Test results cannot be obtained.

Further, the conventional tie bar cutting jig 10
Cuts the tie bar 3 and the dam beam 4 at the same time by the punch 11 and the die 12. However, since the dam beam 4 contains a hard glass filler,
1 and the die 12 were severely worn and the tool life was short.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and when cutting a tie bar, it is possible to effectively remove the tie bar without leaving an angle with the cutting of the tie bar, and to shorten the tool life. An object of the present invention is to provide a long tie bar cutting jig and a tie bar cutting method using the jig.

[0009]

According to a first aspect of the present invention, there is provided a tie bar cutting jig for cutting a tie bar provided outside a semiconductor IC package, comprising a punch and a die, wherein a bottom portion of the punch is provided. A tie bar cutting portion for tie bar cutting, and a portion closer to the package than the tie bar cutting portion protrudes downward to form a burr pressing portion, while the die is fitted with the tie bar cutting portion. The punch fitting portion is disposed so as to retreat in a direction away from the package side than the flash pressing portion.

According to a second aspect of the present invention, in the configuration of the first aspect, the burr pressing portion is formed by forming a single projection at the center of the tip of the bottom surface of the punch.

According to a third aspect of the present invention, in the configuration of the first aspect, the burr pressing portion is formed by forming two projections at the tip of the bottom surface of the punch in parallel in the width direction.

According to a fourth aspect of the present invention, there is provided a tie bar cutting jig for cutting a tie bar provided outside a package of a semiconductor IC, comprising a punch and a die. The tie bar cutting portion is formed, and the tie bar cutting portion is inclined downward toward the package and forms a flash pressing portion at the tip thereof, while the die is fitted with the tie bar cutting portion. A punch fitting portion is provided, and the punch fitting portion is disposed so as to retreat in a direction away from the package side with respect to the flash pressing portion.

According to a fifth aspect of the present invention, after using the tie bar cutting jig according to any one of the first to fourth aspects, the burr pressing portion of the punch crushes the dam beam between the package and the tie bar. The tie bar is cut by the tie bar cutting portion and the die.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 1 is a perspective view showing a part of a tie bar cutting jig, FIG. 2 is a longitudinal sectional view showing a positional relationship between a tie bar cutting jig and a lead frame, and FIG. 3 is a punch, a die and a lead frame of the tie bar cutting jig. It is a top view which shows the positional relationship of.

The tie bar cutting jig 6 of this embodiment
Is provided with a punch 7 and a die 8 for cutting the tie bar 3 provided outside the semiconductor IC package 1. The punch 7 has a substantially rectangular parallelepiped shape as a whole. In order to have a predetermined length from the close position to the outside of the tie bar 3 and to prevent the lead 2 from galling or deformation when cutting the tie bar,
The width dimension of the punch 7 is set to be slightly smaller than the interval between the leads 2 facing each other, as in the related art.

At the bottom of the punch 7, a tie bar cutting portion 7a for cutting a tie bar is formed, and a portion closer to the package 1 than the tie bar cutting portion 7a is projected downward to form a flash pressing portion 7b. Have been. In this embodiment, the flash pressing portion 7b is formed by forming a single semi-cylindrical projection at the center of the tip of the bottom surface of the punch 7. In this case, the shape of the protrusion 7b is not limited to a semi-cylindrical shape, but may be a conical shape, a rectangular parallelepiped shape, or the like.
Any shape may be used as long as the shape can be pressed.

On the other hand, the die 8 is formed with a punch fitting portion 8a into which the tie bar cutting portion 7a of the punch 7 is fitted, and the punch fitting portion 8a is
b so as not to hinder the crushing of the dam beam 4 by the b, in a position avoiding the burr pressing portion 7b, that is, in a direction away from the package 1 side by a predetermined distance L from the package 1 side end of the burr pressing portion 7b It is arranged to retreat. Therefore, even when the tie bar cutting portion 7a of the punch 7 enters the punch fitting portion 8a of the die 8, the punch fitting portion 8a is not located below the flash pressing portion 7b.

In order to remove the tie bar 3 and the dam burrs 4 by using the tie bar cutting jig 6 having this configuration, first, the punch 7 is lowered, and first, the burrs pressing portion 7 of the punch 7 is moved.
b contacts the dam beam 4. At this time, the burrs 7b
Since the die 8 does not exist under the tie bar 3, a bending moment is applied to the dam beam 4 with the joint with the package 1 as a fulcrum, and the entire portion on the tie bar 3 side is crushed. For this reason, the corner 4a unlike the related art does not occur. Therefore, scattering of burrs is prevented in the next lead bending step, and contact failure during testing is greatly improved. Further, since the dam burrs 4 are not directly cut by the punches 7 and the dies 8, the tool life of the punches 7 and the dies 8 can be kept long. When the punch 7 is further lowered, the tie bar 3 is cut between the tie bar cutting portion 7 a and the punch fitting portion 8 a of the die 8.

As shown in FIG. 4, after the tie bar is cut, the conventional burrs do not remain, but the remaining portions 4b of the burrs may be slightly present adjacent to the package 1, as shown in FIG. . However, there is no problem because the remaining portion 4b has almost no influence on the cause of burrs in the next lead bending step.

Embodiment 2 In the tie bar cutting jig 6 described above, the burr pressing portion is formed by the single projection 7b formed at the center of the tip of the bottom surface of the punch 7, but the present invention is not limited to this, and for example, shown in FIG. As described above, it is also possible to form the projections 7c and 7d at the tip of the bottom surface of the punch 7 in parallel in the width direction to constitute the flash pressing portion. In the case of this configuration, as in the case of the first embodiment shown in FIGS.
And the tie bar 3 can be cut.

Embodiment 3 Further, in the tie bar cutting jig of the present invention, the burr pressing portion is not limited to the shapes of the projections 7b, 7c, 7d as shown in FIGS. 1 and 5, and for example, as shown in FIG. Then, a tie bar cutting portion 7a for cutting a tie bar is formed at the bottom of the punch 7, and the tie bar cutting portion 7a is inclined downward toward the package 1 to form a flash pressing portion 7b at the tip end thereof. You can also. Even in that case,
The die 8 is disposed at a position avoiding the flash pressing portion 7b, that is, at a position retracted outward from the lead by a predetermined distance L from the end of the flash pressing portion 7b on the package 1 side. Make it possible to remove Dam 4

Since the dam beam 4 strongly adheres to the cross section of the lead frame, it is preferable to perform an electrolytic deburring step before tie-bar cutting in order to facilitate the peeling of the dam beam 4. By this electrolytic deburring, the interface between the dam burrs 4 and the lead frame is peeled off by an electric force, so that the deburring in the subsequent tie bar cutting step can be performed more easily.

[0023]

As described above, according to the present invention, the following effects can be obtained. According to the tie bar cutting jig of the first and fourth aspects and the tie bar cutting method of the fifth aspect, at the time of the tie bar cutting, not only can the tie bar be reliably cut, but also the dam burrs can be effectively removed without leaving corners. can do. For this reason, the scattering of the corners is eliminated when the lead is bent in the subsequent process, and the contact failure at the time of the test is largely improved, and the test yield is improved. Moreover, since the dam beam is not crushed at the press portion and cut by the punch and the die, the tool life can be kept long,
The running cost of the tie bar cutting jig can be reduced. In particular, if the burrs are formed by projections as in claims 2 and 3, dam burrs can be efficiently removed with a simple configuration.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a part of a tie bar cutting jig according to Embodiment 1 of the present invention.

FIG. 2 is a longitudinal sectional view showing a positional relationship between a tie bar cutting jig and a lead frame according to the first embodiment of the present invention.

FIG. 3 is a plan view showing a positional relationship between a tie bar cutting jig and a lead frame according to the first embodiment of the present invention.

FIG. 4 is a plan view showing a state after a tie bar and a dam beam are simultaneously cut using the tie bar cutting jig of the present invention.

FIG. 5 is a perspective view showing a part of a tie bar cutting jig according to another embodiment 2 of the present invention.

FIG. 6 is a longitudinal sectional view showing a tie bar cutting jig according to Embodiment 3 of the present invention.

FIG. 7 is a plan view showing a state of the semiconductor IC immediately before tie bar cutting.

FIG. 8 is a longitudinal sectional view showing a state where tie bar cutting is performed using a conventional tie bar cutting jig.

FIG. 9 is a plan view showing a state where tie bar cutting is performed using a conventional tie bar cutting jig.

FIG. 10 is a plan view showing a state after a tie bar and a dam beam are simultaneously cut using a conventional tie bar cutting jig.

[Explanation of symbols]

1 Package, 2 leads, 3 tie bars, 4 dam beams, 4a angle beam, 6 tie bar cutting jigs, 7 punches, 7a tie bar cutting portions, 7b, 7c, 7d flash pressing portions, 8 dies, 8a punch insertion portions.

Claims (5)

[Claims] 1. A tie bar cutting jig for cutting a tie bar provided outside a package of a semiconductor IC, comprising: a punch and a die;
While forming a tie bar cutting part for tie bar cutting,
A portion closer to the package than the tie bar cutting portion is projected downward to form a burr pressing portion, while the die has a punch fitting portion into which the tie bar cutting portion is fitted. A tie bar cutting jig for a semiconductor IC, wherein the jig is disposed so as to be retracted in a direction away from a package side than a flash pressing portion. 2. The tie bar cutting jig according to claim 1, wherein the burr pressing portion has a single projection formed at the center of the tip of the bottom surface of the punch. 3. The tie bar cutting jig according to claim 1, wherein the burr pressing portion is formed by forming two protrusions at the tip of the bottom surface of the punch in parallel in the width direction. 4. A tie bar cutting jig for cutting a tie bar provided outside a package of a semiconductor IC, comprising: a punch and a die;
While forming a tie bar cutting part for tie bar cutting,
The tie bar cutting portion is inclined downward toward the package to form a flash pressing portion at the tip thereof, and the die has a punch fitting portion into which the tie bar cutting portion is fitted. A tie bar cutting jig for a semiconductor IC, wherein the fitting portion is disposed so as to recede in a direction away from the package side with respect to the flash pressing portion. 5. The tie bar cutting jig according to claim 1, wherein a bur bar between the package and the tie bar is crushed by the burr pressing portion of the punch, and then the tie bar cutting portion is crushed. A tie bar cutting method characterized by cutting a tie bar with a die.