JP3044443B2 - Lead frame and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead frame in which the tip of an inner lead is supported and fixed by a tape, and a method of manufacturing the same.

[0002]

2. Description of the Related Art A lead frame has a large number of pins due to multifunctionality and miniaturization of a semiconductor device, and both a lead width and a pitch are fine. In particular, the inner leads are miniaturized and easily deformed. Deformation of the inner lead, for example, warping, rising, drooping, lead leaning, etc.
Affects wire-bonding. When the deformation is severe, the lead is short-circuited.

[0003] In order to prevent deformation of the inner lead, an insulating tape is attached to the inner lead and fixed, as disclosed in, for example, Japanese Patent Application Laid-Open No. Hei 4-171859 and Japanese Patent Publication No. 5-79174. The tape is cut into strips, the corners are cut, and the tape is attached as described above. However, this requires many steps and is inferior in workability.

[0004] In addition, there is a type in which a tape punched in a frame shape is continuously attached from an inner lead to a support bar. In this case, the tape sticking operation can be performed at one time and the workability can be improved, but the inner lead close to the support bar may be displaced to the support bar side.
This is inconvenient for wire bonding.

[0005]

In recent years, a tape is stuck to a lead frame having a large number of pins to prevent deformation of the inner lead and secure the wire bonding property. It is applied including. The tips of the inner leads are connected to connecting pieces and pads so as not to be deformed when the tape is stuck, and then punched to separate the tips of the inner leads individually for electrical independence. At this time, the tip of the inner lead and the tape are punched at the same time, but the tape between the end inner lead and the support bar, which are relatively spaced apart, is drawn in the punching direction and the inner lead is deformed. That is, the end inner lead is forcibly shifted to the support bar side, and the inner lead in the middle portion has a shape defect such as warpage.

According to the present invention, there is provided a tape including an end portion of an inner lead, which is attached to a support bar from the inner lead.
When the punch is punched and cut at the same time as the tip of the inner lead, the purpose is to obtain a lead frame with excellent shape accuracy which can be done without deforming the inner lead.

[0007]

SUMMARY OF THE INVENTION The gist of the present invention is to provide a lead frame including a tip portion of an inner lead and a tape continuously attached to a support bar for supporting a pad from the inner lead. The tape attached to the support bar from the outside of the inner lead is on a lead frame in which a part of the pad is cut away. Another gist is that an inner lead is formed on the outer periphery of a pad supported by a support bar, and a tape including the tip of the inner lead is attached to the support bar continuously from the inner lead to form an inner lead. In a method of manufacturing a lead frame in which a lead tip is formed by punching, a partially cut tape is attached from the outside of the end inner lead to the support bar to continuously fix the inner lead and the support bar. And a method for manufacturing a lead frame in which a space between an inner lead and a pad or a tip of an inner lead is punched simultaneously with a tape.

[0008]

According to the present invention, the tape to be attached from the end inner lead to the support bar is partially cut off on the pad side, so that when the tip of the inner lead and the tape are simultaneously punched, the end inner lead is used. Although the distance between the lead and the support bar is wider than the others, it does not engage with the punch and cannot be pulled in.
Thus, the inner leads do not deform and have excellent shape accuracy.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described based on one embodiment with reference to the drawings. In the drawing, reference numeral 1 denotes a pad for mounting a semiconductor chip, which is supported by a support bar-2.
Inner lead 3 between support bar 2 around pad 1
Are formed in large numbers. Reference numeral 4 denotes an outer lead formed continuously with the inner lead 3. 5 is a tie bar
It is. These lead patterns can be formed by a press method or an etching method.

Since the tip of the inner lead 3 is particularly fine and easily deformed, the insulating tape 6 is continuously adhered to the support bar 2 through the tip of the inner lead 3.

The inner lead 3 to which the tape 6 is adhered is punched to have a predetermined length or to separate it from a connecting portion such as a pad. The punching is performed at the same time as the tape 6. However, since the inner lead 3 has been deformed so far, in the present invention, the end inner lead 3a is formed.
The tape 6 to be stuck is partially cut out 6a on the pad side from to the support bar-2.

The shape of the partial cutout 6a is not limited to the anti-ellipse of this embodiment, but may be a semicircle, U-shape, V-shape or the like.

When the tape 6 is attached and the desired lead frame manufacturing process is completed, punching for forming the tip of the inner lead 3 is performed. The punching is performed simultaneously with the tape 6 as described above. At this time, since the tape 6 attached between the end inner lead 3 and the support bar 2 which is wider than the others is partially notched 6a on the pad side, a punch (not shown) can be used. The outer side of the end inner lead 3a does not engage with the tape 6 and does not retract. Thus, the end inner lead 3a is not deformed, and the inner lead 3 facing the middle part of the side of the pad is not warped or lifted, and has a good shape.

[0014]

As described above, according to the present invention, it is possible to obtain a lead frame having excellent shape accuracy without deformation or displacement of the inner leads.

[Brief description of the drawings]

FIG. 1 is a view showing a lead frame according to an embodiment of the present invention.

FIG. 2 is a view showing tape attachment from an inner lead to a support bar in one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pad 2 Support bar 3 Inner lead 4 Outer lead 5 Tie bar 6 Tape 7 Lead frame

──────────────────────────────────────────────────の Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 23/50

Claims (2)

(57) [Claims] In a lead frame including a tip of an inner lead and a tape continuously attached to a support bar supporting a pad from the inner lead, the support bar is attached to the support bar from outside the end inner lead. A lead frame, wherein a part of a tape to be attached is cut off on a pad side. 2. An inner lead is formed on an outer periphery of a pad supported by a support bar, and a tip end portion of the inner lead is included in the pad from the inner lead to the support bar.
In a method for manufacturing a lead frame in which a tape is attached and a tip of an inner lead is formed by punching, a partially cut tape is attached from the outside of the end inner lead to the support bar to attach the inner lead and the support bar. A method for manufacturing a lead frame, characterized in that the tip of the inner lead is punched out simultaneously with the tape while fixing the inner lead.