JP2593365Y2 - Structure of lead frame for electronic parts - Google Patents

Description

[Detailed description of the invention]

[0001]

The present invention relates to a transistor and an IC.
The present invention relates to an improvement in a lead frame used in manufacturing an electronic component in which a semiconductor chip portion is packaged with a thermosetting synthetic resin molded portion among the electronic components.

[0002]

2. Description of the Related Art Conventionally, a lead frame structure used for manufacturing an electronic component in which a semiconductor chip portion is packaged in a thermosetting synthetic resin mold portion is as follows.
For example, as described in JP-A-58-43552 and as shown in FIGS. 7 to 9, an island 2 for mounting a semiconductor chip on a lead frame 1 is integrally formed, and A plurality of lead terminals 3 extending toward the main body are integrally formed, and a damming member (dam bar) 4 is integrally formed between the respective lead terminals 3 to form a synthetic resin mold portion 5. At this time, the synthetic resin in a molten state is configured to be blocked by each of the blocking members 4, while each of the blocking members 4 is
After the molding of the mold portion 5, a punch 6 that moves up and down toward a receiving blade (not shown) disposed on the lower surface side of the lead frame 1 as shown by a two-dot chain line in FIGS.
It is configured to perform punching and cutting.

[0003]

However, in the prior art, the damming member (dam bar) 4 is punched out and cut by a punch 6 after the molding of the mold portion 5, and the damming member 4 is cut off. When the side edge on the mold portion 5 side of the left and right side edge portions in the width direction along the longitudinal direction of the lead terminal 3 is in contact with the side surface of the mold portion 5, the damming member 4 is Can not be cut out and cut off, so that the damming member 4
Must be provided at a position separated by an appropriate dimension (S) from the outer peripheral surface of the mold section 5. Therefore, when the mold section 5 is formed, the outer peripheral surface of the mold section 5 is The molten synthetic resin also enters the gap between the lead terminal 3 and the lead terminal 3.
Inevitably, burrs 5a of the synthetic resin will be generated in a portion between the two.

Accordingly, in the conventional device,. After the molding of the mold portion 5, it is necessary to remove burrs 5a generated at the portions between the lead terminals 3,
Since a great deal of work is required to remove the burr 5a, the cost is greatly increased. . Each damming member 4
When the punch 6 is punched and cut by the punch 6, the punch 6 hangs on the burr 5a of the synthetic resin, in other words, a part of the burr 5a of the synthetic resin is cut by the punch 6, Since the wear of the punch 6 is increased, the durability of the punch 6 is significantly reduced. There was a problem to say.

Further, Japanese Utility Model Application Laid-Open No.
Japanese Patent Application Publication No. 160553 discloses a configuration in which one end on the mold portion side of the right and left ends in the width direction of each damming member is in contact with the side surface of the mold portion, and the lead terminal of the damming member is In the continuous portion, a slit hole extending along the longitudinal side edge of the lead terminal is formed by leaving a continuous portion of a minute length at both left and right edges in the width direction of the damming member, thereby forming a mold portion. In addition to preventing resin burrs from being generated between the side surface and the respective blocking members, the respective blocking members can be easily cut and cut with a light force without deforming the lead terminals. Propose that.

However, in this structure, a slit hole formed in a portion of each of the damming members, which is continuous with the lead terminal, is formed in a rectangular shape having two corners on each of inner surfaces at both ends thereof. By doing so, when this rectangular slit hole is punched and punched with a punch and a receiving die,
The punch shall have an elongated rectangular cross section with two corners at each end, and the receiving die shall be provided with an elongated rectangular die hole having two corners at each inner surface at each end. In addition to requiring a great deal of trouble in drilling an elongated rectangular die hole in the receiving die, chipping is likely to occur at two corners at both ends of the punch, and durability is reduced. Since the punch and the receiving die must be frequently replaced at a low cost, the cost required for forming the slit holes is greatly increased.

Further, as described above, if the slit hole is a rectangle having two corners on each of the inner surfaces at both ends, the shredding in the continuous portion will cause the two corners in the slit hole to be cut off. Of these, it can occur at the corners on the lead terminal side and at the corners farther from the lead terminal.In the latter case, a long metal burr piece is attached to the base of the lead terminal. Therefore, when soldering to a printed circuit board, a solder bridge is generated between the long burr pieces.

For this purpose, a notch groove having a V-shaped cross section is formed in the continuous portion, as described in Japanese Utility Model Application Laid-Open No. 160553/1987. Although the above-mentioned shredding is performed at the location of the groove, since a step of engraving a notch groove in each of the continuous portions must be added for this,
This leads to a further increase in the cost required for manufacturing the lead frame.

It is a technical object of the present invention to provide a lead frame capable of solving these problems at once.

[0010]

In order to achieve this technical object, the present invention provides a method for forming a molded part between a plurality of lead terminals for a semiconductor chip packaged in a synthetic resin molded part. At this time, a blocking member for blocking the molten synthetic resin is integrally formed, and one end edge of the blocking portion of the blocking member is extended so that the one end edge contacts the outer peripheral surface of the molding portion. On the other hand, a slit hole extending along a longitudinal side edge of the lead terminal is formed at a portion of the damming member continuous with the lead terminal at least at one end edge of the damming member on the mold portion side. In a lead frame formed by leaving a continuous portion of the length, the inner surfaces at both ends of the slit hole are formed in a semicircular arc shape. "

[0011]

As described above, the inner surfaces of both ends of the slit hole formed in the damming member are formed in a semicircular arc shape. In this case, the punch can be formed into an oval cross section having no corners at both ends, and the die hole in the receiving die can be formed by making the inner surfaces of both ends into a semi-arc shape. While it is possible to greatly reduce the number of steps required to form a die hole in the receiving die, the durability of the punch and the receiving die is increased, and the frequency of replacing the punch and the receiving die can be reduced.

Further, since the inner surfaces of both ends of the slit hole formed in the damming member are formed in a semicircular arc shape, the continuous cutting of the damming member always cuts a half of the slit hole. Since it occurs at the tip of the arc of the arc-shaped inner surface, even if the step of engraving the notch groove at the place of each of the continuous portions as in the prior art is omitted, the root portion of each lead terminal is omitted. It is possible to reliably prevent long metal burrs from being generated.

Therefore, according to the present invention, not only the cost required for forming the slit holes can be reduced, but also each continuous portion is formed in order to prevent the formation of long metal burrs at the root of each lead terminal. Since the step of engraving the notch groove as in the prior art described above can be omitted, the cost required for manufacturing the lead frame can be greatly reduced.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings (FIGS. 1 to 6). 1 to 3 show a first embodiment. In this figure, reference numeral 10 denotes a lead frame made of a metal plate, and the lead frame 10 has an island portion 12 for mounting a semiconductor chip 11 thereon. A plurality of lead terminals 13 extending toward the island portion 12 are integrally formed.

A portion between the lead terminals 13;
An appropriate width between the outermost lead terminal 13 of the lead terminals 13 and the side frames 20 and 21 of the lead frame 10 for blocking the molten synthetic resin when the synthetic resin mold portion 15 is formed. The dam member (dam bar) 14 having the dimension W is integrally formed.

Then, between the lead terminals 13,
And the lead terminal 13 and both side frames 20, 21
And between each of the damming members 14 in between, the end of the damping member 14 on the side of the mold portion 15 is extended to a state in which it comes into contact with the outer peripheral surface 15a of the mold portion 15. The lead terminals 13 and both side frames 2 on both sides of each damming member 14
A slit hole 17 extending along the longitudinal side edge of the lead terminal 13 is formed at a portion continuous with the first and second terminals 0 and 21 at both left and right edge portions in the width direction of the damming member 14 to have minute lengths t ₁ and t ₂ . The slits 17 are formed in the shape of a semicircle, and the slits 17 are formed in an oblong shape.

As described above, each blocking member 14 is extended such that one end edge of the blocking member 14 on the mold portion 15 side is in contact with the outer peripheral surface 15a of the molding portion 15, so that the At the time of molding, it is possible to reliably prevent burrs of the synthetic resin from being generated at the portions between the lead terminals 13 and between the lead terminals 13 and both side frames 20 and 21.

On the other hand, a slit 17 extending along the longitudinal side edge of the lead terminal 13 is formed in a portion of each of the damming members 14 which is continuous with the lead terminals 13 and the side frames 20 and 21 on both sides thereof. Since the continuous portions 18 and 19 of minute lengths t ₁ and t ₂ are engraved on both left and right edges of the stopper member 14 in the width direction, portions of the respective dam members 14 apart from the mold portion 15. To
As shown by a two-dot chain line in FIGS. 2 and 3, by pressing downward with a punch 16 or the like, minute lengths t ₁ , t ₂ at both left and right ends of the damming member 14 in the width direction.
Since the continuous portions 18 and 19 are easily torn apart, one end of the left and right end portions of each damming member 14 on the mold portion 15 side is in contact with the outer peripheral surface of the mold portion 15. However, each damming member 14 can be extremely easily punched and cut.

In this case, each of the slit holes 17
The inner surfaces of both ends are formed in a semicircular shape, so that when this slit hole 17 is punched and punched with a punch and a receiving die, the punch is formed into an oval cross section having no corners at both ends. In addition to the above, the die hole in the receiving die can be formed into a semicircular inner surface at both ends, so that it is possible to greatly reduce the number of steps of forming the die hole in the receiving die, and The durability of the punch can be improved.

In addition, since the inner surfaces at both ends of the slit hole 17 are formed in a semicircular shape, the portions where the continuous portions 18 and 19 are torn are always changed to the semicircular inner surface in the slit hole 17. Can be limited to the tip of the arc. 4 to 6 show a second embodiment.

In this second embodiment, each damming member 14
Of the lead frame 10 is integrally formed from a connecting bar 22 that connects between both side frames 20 and 21 without appropriately configuring the width dimension W as in the first embodiment. ′. Also in this case, each of the damming members 14 '
Is extended to a state where one end edge of the blocking member 14 ′ on the mold portion 15 side is in contact with the outer peripheral surface 15 a of the mold portion 15, while the respective blocking members 1 ′ are extended.
4 ', the lead terminals 13 on both sides thereof and the portions continuous with the two side frames 20, 21 are provided with lead terminals 1
3 of the slit 17 extending along the longitudinal side edges, leaving a continuous portion 18 minute length t ₁ (part without slit) at one edge of the mold 15 side of the dam member 14 ' The inner surfaces of both ends of the slit hole 17 are formed in a semicircular shape.

Accordingly, when molding the molded portion 15, the occurrence of burrs of the synthetic resin in the portions between the lead terminals and between the lead terminals 13 and both side frames 20, 21 is prevented. On the other hand, a part of each of the damming members 14 ′ that is apart from the mold part 15 is, as shown by a two-dot chain line in FIGS.
By pressing downward with 6 'or the like, the continuous portion 18 having a minute length t1 at _one end edge of the damming member 14' is easily torn off, and each damming member 14 'is broken.
Is an extension of each of the damming members 14 ′ such that one end edge on the mold portion 15 side thereof is in contact with the outer peripheral surface of the mold portion 15 because it is bent downward as indicated by a two-dot chain line. However, the respective damming members 14 'can be extremely easily punched and cut.

Further, since the inner surfaces at both ends of the slit hole 17 are formed in a semicircular arc shape, the portion where the continuous portion 18 is torn is always changed to the slit hole 17.
Can be limited to the tip of the arc of the semi-circular inner surface in the above.

[Brief description of the drawings]

FIG. 1 is a plan view of a lead frame showing a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view taken along line II-II of FIG.

FIG. 3 is an enlarged perspective view showing a main part of FIG. 1;

FIG. 4 is a plan view of a lead frame showing a second embodiment of the present invention.

FIG. 5 is an enlarged sectional view taken along line VV of FIG. 4;

FIG. 6 is an enlarged perspective view showing a main part of FIG. 4;

FIG. 7 is a plan view of a conventional lead frame.

FIG. 8 is an enlarged sectional view taken along line VIII-VIII of FIG. 7;

FIG. 9 is an enlarged perspective view showing a main part of FIG. 7;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Lead frame 11 Semiconductor chip 12 Island part 13 Lead terminal 14, 14 'Damming member 15 Mold part 16, 16' Punch 17 Slit hole 18, 19 Continuation part

Continuation of the front page (56) References JP-A-60-84850 (JP, A) JP-A-2-129954 (JP, A) JP-A-2-105448 (JP, A) JP-A-63-70548 (JP) JP-A-58-56360 (JP, A) JP-A-62-160553 (JP, U) JP-A-62-116560 (JP, U)

Claims (1)

(57) [Scope of request for utility model registration] A plurality of lead terminals for a semiconductor chip packaged in a synthetic resin mold portion;
The integrally by molding the dam member for damming molten synthetic resin during molding of the molded part, this dam
One end edge on the mold side of the member,
While extending so as to contact the outer peripheral surface of the mold portion,
A portion of the damming member that is continuous with the lead terminal
A slit hole extending along the long side edge of the lead terminal
At least the mold portion of the damming member
Perforated by leaving a small length continuous part at one edge of the side
In the lead frame, the inner surfaces at both ends of the slit hole are formed in a semicircular shape.
Electronic component structure of the lead frame, characterized in that it has.