JPH09205173A - Manufacture of lead frame - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lead frame in which inner leads and bus bars have excellent flatness without any twist and tilt and onto which adhesive insulating tape can tightly be stuck with its good flattening without its local peeling off or improper adhesion. SOLUTION: In the method for manufacturing a lead frame having inner leads and bus bars which are intended to have a semiconductor chip mounted on their lower or upper surfaces, a plate is blanked so that at least inner leads 1 or bus bars 2 are connected at their intermediate parts by connecting pieces 9. After the plate is annealed, the connecting pieces 9 are removed from the plate. In this case, the removal of the connecting pieces 9 is carried out after the annealing and before the removal the pieces 9, by applying pressure sensitive adhesive double coated insulating tape onto the inner leads 1 and bus bars 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a lead frame in which a semiconductor chip is provided on the inner lead or the lower or upper surface of a bus bar.

[0002]

2. Description of the Related Art A semiconductor device is required to have high functionality, high responsiveness, and downsizing, and in response to this, high integration of a semiconductor chip, a structure of a semiconductor device for increasing a semiconductor chip area ratio, and shortening of wiring in the semiconductor device. Etc. are being considered. For example 4
There is a type in which inner leads of a lead frame are provided on the upper surface of a semiconductor chip with an insulating tape interposed therebetween such as No. 1503. This makes it possible to use semiconductor chips as large as they are stacked, and to shorten the connection wiring between the chip terminals and the inner leads, which has the effect of speeding up signal response and reducing impedance.

[0003]

In the lead frame of such a semiconductor device, when the insulating tape is attached, the inner leads or the bus bars formed between the opposing inner leads have poor flatness. The insulation tape may be stuck and may come off. Further, thereafter, when the semiconductor chip is installed on the lower surface or the upper surface of the inner lead or the bus bar, problems such as defective adhesion and peeling occur, and the reliability of the semiconductor device is impaired.

An object of the present invention is to obtain a lead frame which has excellent flatness of the inner leads and the bus bar and does not have the above problems.

[0005]

The gist of the present invention is to provide a method for manufacturing a lead frame in which a semiconductor chip is mounted on the lower surface or the upper surface of an inner lead or a bus bar, wherein at least one of the inner lead and the bus bar has an intermediate portion. This is a method for manufacturing a lead frame in which a connecting piece is punched and annealed in a state of being connected, and then the connecting piece of the intermediate portion is removed. Another gist is to remove the connecting piece after attaching the double-sided adhesive insulating tape to the inner lead and the bus bar for mounting the semiconductor chip after the annealing and before removing the connecting piece in the intermediate portion. It is in.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, at the time of punching and forming the inner lead and the bus bar of the lead frame, at least one of the intermediate portions is connected by a connecting piece. Therefore, even if the inner lead is thin, Even if -is thin and long, it is not deformed and is formed while maintaining a predetermined flatness. After annealing, the connecting piece in the middle part is removed, and the shape is excellent without twisting or tilting. Thus, the double-sided adhesive insulating tape adhered for mounting the semiconductor chip on the lower surface or the upper surface of the inner lead or the bus bar is adhered in the same horizontal plane without any local peeling or adhesion failure. It

In addition, after forming an intermediate portion of at least one of the inner lead and the bus bar by connecting with a connecting piece and annealing, the double-sided adhesive insulating tape is attached to the inner lead before punching and removing the connecting piece. Even if it is adhered to a bus bar and then the connecting piece is punched out together with the double-sided adhesive insulating tape, the double-sided adhesive insulating tape can be used in the same manner without causing defective adhesion on the inner leads and the bus bar. It is stuck tightly.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the drawings, 1 is a large number of inner leads, and a bifurcated bus bar-2 extends in front of the tip of the inner leads 1 on both sides of the inner lead 1 group. It is formed as follows. The bus bar-2 is used as an operation power supply lead and a ground power supply lead. The group of inner leads 1 and the bus bar-2 are provided so as to face each other with the semiconductor chip mounting region 3 interposed therebetween.

An outer lead 4 is continuous with the inner lead 1 and the bus bar-2, and a tie bar 5 is formed at the boundary thereof. 6 is a side rail, 7 is a guide wheel
Reference numerals 8 are slits for absorbing the deformation caused by the difference in thermal expansion between the lead frame and the resin when the resin is sealed.

These lead patterns are formed by pressing in view of productivity, shape uniformity and cost.
Since the inner lead 1 is thin and weak in strength and easily deformed on the way, and the bus bar-2 has a long lead portion and is also easily deformed, at least one intermediate portion is connected by the connecting piece 9 in the present invention. It is formed by press working in the state. In addition,
In this embodiment, a connecting piece 9 is provided in the intermediate portion of both the inner lead 1 and the bus bar-2.

It is preferable that the intermediate portion where the connecting piece 9 is provided on the inner lead 1 is located inside the tip close to the wire bonding portion. As an intermediate portion of the connecting piece 9 provided on the bus bar-2, a portion connected to the facing bus bar-2a on the side near the terminal end extending forward of the tip of the inner lead 1 is preferable.

The location of the connecting piece 9 is not specified, but may be an appropriate location depending on the shape or length of the inner lead 1 or the bus bar-2 in the middle.

Since a processing residual stress is generated in the formation of the lead pattern, it is annealed so as to release or reduce the residual stress. After that, the inner lead 1 and the bus bar-2
The connecting piece 9 connecting the intermediate portions of is punched out and removed.

Then, a double-sided adhesive insulating tape is attached to the semiconductor chip installation region 3 shown by the one-dot chain line. The double-sided adhesive insulating tape is attached to the lower surface of the inner lead 1 and the bus bar when the semiconductor chip is placed on the lower surface. Further, when it is installed on the upper surface, it is provided on the upper surfaces of the inner lead 1 and the bus bar.

Prior to removing the connecting piece 9, a double-sided adhesive insulating tape 10 is attached to the semiconductor chip installation area 3 as shown in FIG. 2, and then the connecting piece 9 is removed. Good.

[0016]

As described above, according to the present invention, since at least one of the inner leads and the bus bar is punched and formed in the state where the intermediate portions are connected by the connecting pieces, there is no lead twist or inclination, and the flatness is excellent. After annealing, the double-sided adhesive insulating tape can be adhered to the lower surface or the upper surface of the inner lead or the bus bar with good adhesion and no peeling or adhesion failure occurs.

Further, since the intermediate portion of the inner lead and the bus bar is connected by the connecting piece, the lead is removed during the manufacturing process.
Do not deform. Therefore, in the lead frame according to the present invention, the semiconductor chip is mounted via the inner lead, the double-sided adhesive insulating tape adhered to the lower surface or the upper surface of the bus bar, and a highly reliable semiconductor device can be manufactured.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a lead frame according to another embodiment of the present invention.

[Explanation of symbols]

 1 Inner lead 2 Bus bar 3 Semiconductor chip installation area 4 Outer lead 5 Tie bar 6 Side rail 7 Guide rail 8 Slit 9 Connecting piece 10 Double-sided adhesive insulating tape

Claims (2)

[Claims] 1. A method of manufacturing a lead frame in which a semiconductor chip is mounted on the lower surface or the upper surface of an inner lead or a bus bar, wherein at least one of the inner lead and the bus bar is punched and formed in a state of being connected by a connecting piece. ,
A method of manufacturing a lead frame, which comprises annealing and removing the connecting piece of the intermediate portion. 2. A method of manufacturing a lead frame in which a semiconductor chip is mounted on the lower surface or the upper surface of an inner lead or a bus bar, in which at least one intermediate portion of the inner lead and the bus bar is punched and formed in a state of being connected by a connecting piece. ,
A method for manufacturing a lead frame, which comprises annealing, and attaching a double-sided adhesive insulating tape to an inner lead and a bus bar on which a semiconductor chip is installed to remove the connecting piece of the intermediate portion.