JPH0298165A - Lead frame for electronic component and manufacture of electronic component using the same - Google Patents

Abstract

PURPOSE:To prevent the burr of a resin sealer without using an expensive die by extending damup tongue pieces from a coupler for coupling to support a plurality of lead frames between adjacent leads for a semiconductor device, and disposing the ends of the pieces near the boundary line of the resin sealer. CONSTITUTION:A lead frame 20 has an island 11 for mounting a semiconductor chip, a plurality of leads 12 formed on the periphery of the island 11 and couplers 13 for coupling the leads 12. Damup tongue pieces 18 are extended from a plurality of the couplers 13 for coupling to support the leads 12 between the adjacent leads 12, and disposed at the ends near the boundary line X of a resin sealer 15. The pieces 18 are removed by cutting together with the couplers 13 at bases 18a isolated relatively remotely from the ends through a resin sealing step to prevent the burr of the sealer 15 without using an expensive die.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention includes + IC, LS1. Particularly regarding lead frames used in resin mold sealed semiconductor devices such as power transistors and small signal transistors, or lead frames used in resin mold sealed connectors with a large number of leads extending outside. The present invention relates to an improvement in a lead frame that can prevent resin from flowing out of the mold through the leads during resin molding, thereby preventing the occurrence of flash.

(Prior Art) An example of a conventional lead frame for a semiconductor device is shown in FIG. This lead frame 10 includes an island 1 for mounting a semiconductor chip, a plurality of leads 2 for connecting bonding wires, a dam bar 3 that connects these leads 2 in the middle of extension, and a frame portion 4 that supports the leads 2. It is equipped with The lead 2 extends from the frame portion 4 toward the island 1, and its tip is close to the island 1.

In this lead frame 1o, a semiconductor chip (not shown) is mounted on the island 1 and wire bonded, and then the inside of the resin sealing boundary line X shown in FIG. 4 is sealed by resin molding. This resin molding is applied to the lead frame 1 as shown in FIG.
0 is sandwiched between upper and lower molds 6 and 7, and resin is press-fitted into the space C. At this time, the resin overflows into the gap between each lead 2.2, so remove it from the dam bar 3.
It is designed to stop at . However, Dambar 3 is
It is provided at a position a predetermined distance away from the boundary line X. This is because, although this dam bar 3 will be cut out later to separate each lead 2, in this cutting process, sufficient spacing is required to prevent the cutting teeth from contacting and damaging the resin sealing body 5. This is because it is necessary to set the Therefore, there is a gap S between each part 2 on the tip side of the dam bar 3.
is formed, and the formation of a paris 5a (Fig. 5) inside this paris is unavoidable. A part of this paris 5a will later be formed into the dam bar 3.
However, particles of high hardness may be mixed into the sealing resin, and in such a case, the wear of the cutting teeth is accelerated.

In order to eliminate the occurrence of this paris 5a, FIG.

As shown in FIG. 7, a piece 7a for filling the gap S is also implanted in the molding die 7. However, such molds require high precision, making them difficult to manufacture and expensive.

The top 7a is easily worn out and cannot withstand long-term use.

Further, a slight gap inevitably forms in the gap around the frame 7a. Therefore, in any case, a step of removing the paris by shot blasting or the like is required afterwards.

The same situation applies to resin-molded connectors in which a large number of leads extend outside the resin-sealed body.

(Problems to be Solved by the Invention) Accordingly, one object of the present invention is to prevent the occurrence of burr on a resin-sealed body without using an expensive mold, thereby completely omitting the subsequent burr removal step, Another object of the present invention is to provide a lead frame that can suppress wear of the cutting teeth when separating each lead, and a method of manufacturing a semiconductor device using the lead frame.

(Means for Solving the Problems) In the present invention, in order to solve the above problems, a damming tongue piece 18 is provided between adjacent leads 12 from a connecting portion 13 that connects and supports a plurality of leads 12. It was extended, and its tip was brought close to the boundary line X of the resin sealing body 15. After the damming tongue piece 18 undergoes a resin sealing process, it is cut off together with the connecting portion 13 at a base portion 18a relatively far away from its tip.

(Function) The lead frame 20 of the present invention has upper and lower molds 16.
When a semiconductor chip or the like is resin-sealed between the leads 17 and the leads 12, the gap between each lead 12 from the connecting portion 13 to the resin-sealing boundary line X is filled with the damming tongue piece 18. When injecting the resin, the tips of the damming tongues 18 prevent the resin from overflowing between the leads 12, so that the sealing resin does not form between the leads 12. Therefore, a subsequent deburring step is not necessary. This damming tongue piece 18 is cut off together with the connecting portion 13 in the step of separating the leads 12 from each other. Since the base portion 18a of the damming tongue piece 18 is located relatively far from the side surface of the resin sealing body 15, there is no risk of damaging the resin sealing body 15 with the cutting teeth during the cutting process.

There is less wear because the cutting teeth themselves do not come into contact with the highly hard particles mixed in the sealing resin.

(Example) An embodiment of the present invention is shown in FIGS. 1 to 3.

Figure 1 is a plan view of a part of the lead frame, Figure 2 is a sectional view taken along the line n--n in Figure 1 during the molding process of the sealing resin, and Figure 3 (A) is the weir after resin sealing. FIG. 3B is a plan view of a portion of the lead frame before the stop tongue is removed, and FIG. 3B is a plan view of a portion of the lead frame after the stop tongue is removed.

In FIGS. 1 to 3, the lead frame 20 includes an island 11 for mounting a semiconductor chip (not shown).
and a plurality of glues provided around this island 11.
The lead 12 has a connecting portion 13 that connects the leads 12 to each other. The lead 12 extends from the frame portion 14 toward the island 1, and one end is close to the island 1.

A bonding wire (not shown) is later connected between one end of the lead 12 and the semiconductor chip.

The leads 12 are interconnected by connecting portions 13 in the middle of their extension. A damming tongue piece 18 is provided between each lead 12.12 on the distal side of the connecting portion 13. This damming tongue piece 18 extends from the connecting part 13 to one end side of the lead 12, and its tip reaches the vicinity of the resin sealing boundary line X, and its base part 18a side is reduced and continues to the connecting part 13. There is. The damming tongue piece 18 is formed, for example, by punching out the lead frame from a metal strip at the same time as when it is punched and formed, and then the bending of the base part 18a is corrected by pressing so that it extends on the same plane as the lead 12. Form. Therefore, the width of the notches 19 on both sides that partition the damming tongue piece 18 is extremely small. The notch 19 includes bent portions 19a that are bent inward at the base 18a of the tongue piece 18, facing each other.

Therefore, this lead frame 20 has an island 11
After mounting a semiconductor chip (not shown) thereon and performing wire bonding, resin is molded within the resin sealing boundary line X shown in FIG. 1 to seal it. This resin molding is performed, for example, by sandwiching the lead frame 20 between upper and lower molds 16 and 17 and pressing resin into the space C, as shown in FIG. At this time, the resin is
The lead 2.2 is dammed by the damming tongue piece 18.
leakage to other areas is prevented.

The damming tongue piece 18 is cut off together with the connecting portion 13 along the cutting line shown by the imaginary line in FIG.

Since the cutting line crosses the bent portion 19a of the notch 19, there is no need to control the position of the cutting teeth with high precision in order to cut off the damming tongue piece 18. Also,
Since the base 18a of the damming tongue piece 18 is located relatively far from the side surface of the resin sealing body 15, there is no risk of damaging the resin sealing body 15 with the cutting teeth during the cutting process. Since it does not come into contact with hard particles mixed in the sealing resin, there is less wear.

Although the case where the present invention is applied to a lead frame for a semiconductor device has been described above, the present invention is not limited thereto. The present invention can be applied to lead frames for all other electronic components, such as connectors in which a large number of leads extend outside of a resin-sealed body.

(Effects of the Invention) As described above, in the present invention, the damming tongue piece 18 is extended between the leads 12 from the connecting part 13 that connects and supports the plurality of glue parts 12, The leading end was brought close to the boundary line X of the resin sealing body 15 to form a lead frame. After the damming tongue piece 18 undergoes a resin sealing process, it is cut off together with the connecting portion 13 at a base portion 18a relatively far away from its tip. Therefore, in the resin sealing process, the damming tongue piece 18 can prevent the resin from flowing out between the leads 12 and prevent the resin sealing body 15 from forming flakes. Therefore, there is no need to use a precise and expensive mold, and the process of removing paris can be completely omitted. The cutting teeth used to cut off each lead 12 do not come into contact with the edges, so they are less abrasive and can withstand long-term use. Therefore, the manufacturing cost of electronic components such as semiconductor devices can be significantly reduced.

[Brief explanation of drawings]

1 to 3 show one embodiment of the present invention, in which FIG. 1 is a plan view of a part of the lead frame, and FIG. 2 is the line shown in FIG. 3(A) is a plan view of a part of the lead frame after resin sealing and before the damming tongue is removed; FIG.
B) is a plan view of a part of the lead frame after removing the damming tongue, and FIGS. 4 to 6 show conventional examples, and FIG. 4 is a plan view of a lead frame for a semiconductor device. Figure 5 shows the fourth step in the sealing resin molding process.
FIG. 6 is a cross-sectional view showing another example of the molding die, and FIG. 7 is a cross-sectional view taken along the line ■--■ in FIG. Island lead connection part dam stop tongue piece cut lead frame Patent applicant Goto Seisakusho Co., Ltd. Agent Patent attorney Tadashi Otsuka Figure 1 ++ Figure 2 [・ Figure 3 (A) Figure 3 (B) 20... Lead frame Fig. 4 Fig. 5 Fig. 6 Fig. 7

Claims (6)

[Claims] (1) In a device having a plurality of leads whose one ends are sealed with resin and a connecting portion connecting these leads to each other outside the resin sealing portion, the connecting portion between each of the leads is 1. A lead frame for an electronic component, characterized in that a damming tongue piece is provided that extends from the resin sealing part side toward the resin sealing part side and has a tip end close to the resin sealing boundary line. (2) The electronic component according to claim 1, wherein the damming tongue extends so as to substantially fill the spaces between the leads, and the base side is reduced and continues to the connecting portion. Lead frame. (3) The lead frame is sandwiched between two upper and lower molds to mold a resin sealing body, and then the base of the damming tongue is cut off along with the connecting portion to separate the leads from each other. Method of manufacturing electronic components. (4) The above-mentioned device having an island for mounting a semiconductor chip, a plurality of leads for connecting bonding wires whose ends are provided close to the island, and a connecting portion connecting these leads to each other. A semiconductor device characterized in that a damming tongue piece is provided between each lead, extending from the connecting portion to one end side of the lead, and having a tip end close to the boundary line of the resin sealing body. lead frame. (5) The semiconductor device according to claim 4, wherein the damming tongue extends so as to substantially fill the space between the leads, and the base side is reduced and continues to the connecting portion. Lead frame. (6) After mounting a semiconductor chip on the island and performing wire bonding, the lead frame is sandwiched between upper and lower molds and a resin sealing body is molded, and then the dam tongue piece is attached together with the connecting portion. 1. A method of manufacturing a semiconductor device, comprising cutting out a base of the lead to separate the leads from each other.