KR100280086B1 - Lead Frame Structure of Semiconductor Package - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forming method and a structure of a semiconductor package, and includes a raw material inspection, a sawing process, a die bonding process, a wire bonding process, a molding process, a marking process, a trimming process, a forming process, and an inspection. In the manufacturing process of a semiconductor package, in order to precisely bend each lead during the forming process, a defect is formed during forming of the package by forming a notch in a direction parallel to the package in the forming part of the lead before the molding process. It is to improve the reliability of the package by preventing the flatness and bending to be suppressed.

Description

Lead Frame Structure of Semiconductor Package

1 is a front view showing a state before forming of a semiconductor package.

2 is a front view showing a state after forming the semiconductor package.

3 is an enlarged view of a lead in which a forming process is completed in a conventional semiconductor package.

4 is a front view showing a defective state of a lead after forming of a conventional semiconductor package.

5 is a plan view showing a pre-forming state of the semiconductor package of the present invention.

6 is an enlarged cross-sectional view of a preforming state of a lead formed by the present invention.

7 is an enlarged cross-sectional view of a post-forming state of a lead formed by the present invention.

8 is an enlarged view of a solder plated state of a lead formed by the present invention.

* Explanation of symbols for main parts of the drawings

10: semiconductor package 1: lead

2: Notch 3: Plating solution

The present invention relates to a lead frame structure of a semiconductor package, and more particularly, to a lead of a semiconductor package which improves reliability of a package by suppressing defects of leads generated during forming of the semiconductor package to prevent flatness and bending. Frame structure.

In general, the manufacturing process of the semiconductor package is largely inspection of raw materials to check wafer defects, sawing process of cutting the wafer into pieces, and die bonding process of attaching the separated semiconductor chips to the mounting plate of the lead frame. Wire bonding process that connects chip pad and lead frame lead on semiconductor chip with wire, Plating process to improve molding power and protect package, Internal circuit of semiconductor chip and other components Molding process to cover the outside with mold compound for protection, marking process to write letters and symbols (material unique number, company name, date, etc.) on the bottom of the package to identify the package, connecting lead and lead Trim process for cutting dam bar, forming process for bending lead to desired shape, and defects of package completed through the above process It consists of the process of inspection.

At this time, the forming process is to bend the lead 1 of the semiconductor package 10 in the same state as the second degree by using the forming tool frame of the lead 1 of the semiconductor package 10 in the same state as the first degree of the desired type By forming the lead 1, the flatness of the lead 1 should be kept constant so that the lead 1 is not opened when the semiconductor package 10 subjected to the forming process is mounted on the motherboard. That is, the semiconductor package 10 that has been formed must maintain a state in which all leads 1 are equally bent with a flatness.

However, the conventional semiconductor package 10 is manufactured for the purpose of merely transmitting a signal that the lead 1 operates in the operation of the semiconductor chip, and when forming the lead of the semiconductor package, As shown in the figure, the inner portion of the bent portion is wrinkled not only aesthetically good, but also shortened its life.

In addition, since the lead 1 is made of a metal material, there are many problems in forming the lead 1 by maintaining a flatness of a certain height because of the property of being restored to its original position by the inherent elastic force of the metal. The correct flatness was maintained by inspecting and correcting a package whose flatness was incorrect due to the elastic force of (1).

In addition, when the leads 1 of the semiconductor package 10 are formed, if each of the leads 1 does not have a flatness, the leads are opened when the semiconductor package is mounted on the motherboard, which causes the defect of the package. will be.

As described above, when the lead of the semiconductor package is formed by the conventional forming method, the flatness cannot be maintained accurately, and it is used as it is even if a certain amount of warpage occurs. However, at present, where the high quality of semiconductor packages is required, the flatness of the formed leads must be formed within 2.5 mils.

Accordingly, the present invention was invented to solve such a problem, and by forming a notch in a portion of the lead formed before the forming process of the semiconductor package, the property to be restored by the elastic force of the lead during forming of the semiconductor package is suppressed. The purpose of the present invention is to provide a lead frame structure of a semiconductor package capable of improving the quality and reliability of a package by forming leads in a uniform state to maintain accurate flatness and preventing warpage.

In order to achieve the object of the present invention, in the manufacturing process of the semiconductor package consisting of raw material inspection, sawing process, die bonding process, wire bonding process, molding process, marking process, trimming process, forming process and inspection, This can be done by forming a notch in the direction parallel to the package on the molded part of the lead prior to the molding process for accurate bending of the lead.

That is, in forming process of bending lead by forming notch in the lead frame of the semiconductor package, the lead is bent constantly to maintain accurate flatness, thereby preventing bending and improving package reliability. Let's do it.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 5 is a plan view showing a state before the lead forming process of the lead formed in the semiconductor package of the present invention, wherein the lead 1 has a notch (2: Notch) is formed. Here, the notches 2 formed on the leads 1 are formed on the top and bottom surfaces of the leads 1 to bend the leads 1 of the semiconductor package 10 into a hook type. That is, the notch 2 is formed at the portion to be bent at the time of forming.

The depth of the notch 2 is formed within a range of 1/2 of the thickness of the lead 1 of the lead frame so as not to affect the opposite surface on which the notch 2 is not formed. In addition, the surface of the notch 2 of the lead 1 may be plated using a plating solution 3 such as solder to fill the notch 2 on the surface where the notch 2 is formed to maximize the effect. .

Thus, in order to form the notch 2 in the lead 1 of the lead frame, the notch 2 may be formed in advance from the raw material of the lead frame, and the notch may be formed in the lead 1 of the lead frame before the forming process during the semiconductor manufacturing process. 2) may be formed.

The notch 2 formed as described above minimizes the elastic force to be restored by the notch 2 during the forming process of forming the lead 1 in the semiconductor manufacturing process. A constant bending state can be maintained between the leads 1. In other words, it is possible to obtain the correct flatness to prevent bending.

In addition, the notch 2 prevents wrinkles generated inside the bent portion of the lid 1 so that the appearance is beautiful and the position of the lead 1 that is bent during forming can be accurately maintained. That is, since the said notch 2 is formed in a fixed position by a metal mold | die, it is possible.

As can be seen from the above description, according to the present invention, in the forming process of bending the lead during the manufacturing process of the semiconductor package, it is possible to improve the quality and reliability of the package by keeping each lead constant to maintain accurate flatness and to prevent bending. There is an effect such as.

Claims (2)

In a lead frame comprising a chip mounting plate to which a semiconductor chip is attached, a plurality of leads extending outwardly from a periphery of the chip mounting plate, and a tie bar supporting the chip mounting plate, the plurality of leads each The first and second bent portions and the first and second bent portions have notches formed on the bottom and top surfaces thereof, respectively, so that the bottom of the plurality of leads bent after forming has a flatness within 2.5 mils. A lead frame structure of a semiconductor package, characterized in that it has a. The lead frame structure of a semiconductor package according to claim 1, wherein a lead surface including the notch is solder plated.