KR970010677B1 - Structure of a lead frame - Google Patents

Abstract

A lead frame being of a zigzag shape which is suitable for manufacturing a semiconductor having many terminals is disclosed. The lead frame includes a outer lead which is intruded from a side of a semiconductor package to outer; a rear lead which is intruded from a rear side of the semiconductor; and an inner lead which is eclectically connected with a bonding pad of a semiconductor chip in the package thereby to connect electrically an inner circuit and an outer circuit with each other.

Description

Leadframe structure

1 shows a conventional lead frame structure,

2 shows the lead frame structure of the present invention,

3 is a structure in which a semiconductor chip is coupled to the present device,

4 and 5 show the packaged state.

* Explanation of symbols for the main parts of the drawings

11,31: Semiconductor chip 12,22,32,42,52: External lead

13,33: wire bond 14,34: pad

25,35,45,55: Rear lid 45,56: Semiconductor package

17,27,37,57: Internal lead

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead frame of a semiconductor device, and more particularly to a lead frame structure fabricated in a zigzag shape to be suitable for manufacturing a semiconductor device having a large number of terminals.

In the semiconductor device packaging method, after the wafer fabrication process is completed, the semiconductor chip is separated and cut into individual semiconductor chips from the wafer, and the semiconductor chips separated by the wings are attached onto the lead frame.

Then, in the wire bonding process, the bonding pads on the surface of the semiconductor chip and the inner lead of the lead frame are connected to each other to electrically connect the internal circuit and the external terminal (lead terminal).

Then, molding with epoxy resin and the like, and separating lead terminals, respectively, and forming a predetermined shape to complete the device package work.

These devices form various types of external leads to be suitable for mounting on a printed circuit board.

At this time, according to the shape of the external lead formed, it is called J-shaped J-lead, Wing-shaped Gullwing-lead, butterfly-shaped Butt-lead, and DIP, SIP, ZIP type is inserted into the printed circuit board and soldered On the other hand, SOJ, SOP, TSOP and QFP types in the shape of J-lead or Gullwing-lead are surface-mounted on a printed circuit board.

In the conventional leadframe structure, the number of out terminals is determined within a prescribed package size, so that there is a certain type of in / out signal to be input and output through the inner lead and the outer lead.

The internal and external leads of these signals come in various forms depending on TSSOP, TSOP, SOJ, ZIP, etc.

1 shows a conventional leadframe structure.

Referring to the drawings briefly described in the prior art as follows.

A conventional lead frame structure as a DIP (Dual In-line Package) type is as follows.

As shown in FIG. 1, several outer leads 12 serving as substrate constant speed terminals and corresponding inner leads 17 protrude to both outer sides of the package.

In the semiconductor device, in order to connect the internal circuit of the semiconductor chip 11 with an external circuit, a pad 14 is formed on the surface of the chip, so that the pad 14 and the inner lead of the lead frame in the semiconductor chip 11 are formed. ) Is contacted by the wire bond 13.

After the package of the semiconductor chip 1l is completed, the external lead 12 is bent into a predetermined shape to be manufactured into an insert type or a surface mount type to have a structure such as TSOP, SOJ, JIP, or the like.

Such various types of internal / external leads may be in various forms such as TSSOP, TSOP, SOJ, ZIP, etc., but the internal structure is configured as a single form.

In this way, the conventional device is a multi-pin package, so that the number of terminals is increased so that the area occupied by the component is too narrow, and the lead spacing is narrowed. Possibility of defect may occur due to the phenomenon.

Therefore, since the number of terminals is limited for a certain package size, the size of the package must be increased to increase the number of terminals.

In addition, there is a technical limitation because the lead spacing is narrowed according to the tendency of the package to be smaller, and the lead spacing is narrow at the time of punching after completion of the package.

The present invention aims to provide an excellent lead frame structure that can solve such a conventional problem and make the package smaller while reducing the surface mounting area.

In the present invention, a part of the inner lead of the lead frame is bent to protrude out of the package mold so that it can be used as an outer lead.

Hereinafter, the present invention will be described in detail with reference to FIGS. 2 through 5.

First, FIG. 2 illustrates a package structure in which a Butt Lead Package (BLP) is mixed and a lead frame structure of a semiconductor device.

The lead frame structure of the present invention is a package structure using a BLP type and a semiconductor device. The lead formed outside the semiconductor package is formed as an outer lead 22 and a rear lead 25 (BLP lead) and is formed in a zigzag pattern.

The rear lead is a BLP type lead and the outer lead is a TSOP, Small Outline J-Bend (SOJ) type or ZIP (Zigzag-inline-package) type lead.

The corresponding inner lead 27 for each lead is formed to connect with the pad of the semiconductor chip as in the prior art.

FIG. 3 illustrates a bonding state in which a semiconductor chip is placed on FIG. 2.

As shown in FIG. 3, the individual semiconductor chips 31 separated from the wafer are electrically connected to external circuits by the structure of the electrical connection terminals protruding from both sides of the body, ie, leads. Each one is bonded to the inner lead 37 and the wire 33.

The inner lead is alternately connected to the outer lead 32 and the rear lead 35 formed by zigzag.

Here, the rear lid 35 is in the same line as the package mold or has a shape that protrudes from the mold portion of the lid.

The zigzag lead can reduce the size of the package to enable high density mounting.

In particular, in the case of a PLCC (Plastic Leaded Chip Carrier) in which high-density mounting falls at the time of mounting, the high-density mounting is possible by supplementing the problem.

4 illustrates a structure in which an external lead is bent to a predetermined shape by completing a semiconductor package.

As shown in the bottom view of FIG. 4B, the rear lid 45 and the outer lead 42 are formed in a zigzag, so that the package 46 can be miniaturized.

(A) and (b) of FIG. 5 show another example of the bottom surface of the lead frame and the packaged device. The structure of the lead is outside the semiconductor package 56, and the outer lead 52 and the rear lead 57 are zigzag. It is a structure to be formed.

In FIG. 5B, the portion of C may be used in combination with Vcc or GND, or may be deleted if unnecessary. When processed with GND, it can also be used as a noise replacement circuit.

By applying the lead frame structure according to the present invention, the same package has an effect of widening the distance between the connection terminals and accommodating more connection terminals.

In addition, in the case of a package having connection terminals of the same outlead, there is an effect that can reduce the size of the package.

In particular, when applied to the PLCC type, which has low directivity when mounting on a board, there is an effect of increasing the mounting adequacy when mounting parts.

The present invention can obtain a mounting effect by applying to various types of packages to have a bent form.

Claims (7)

In a lead frame structure of a semiconductor device, an external lead protruding from the side of the semiconductor package to the outside, a rear lead protruding from the back of the semiconductor package, and the external lead and the rear lead are bonded to the bonding pad of the semiconductor chip within the semiconductor package. And an internal lead connected to electrically connect the internal circuit and the external circuit. 2. The leadframe structure of claim 1, wherein the back lead is flush with the package mold. The leadframe structure according to claim 1, wherein the rear lid protrudes from the mold portion of the lid of the package. The lead frame structure as claimed in claim 1, wherein the outer lead is an insertion type that is bent into a predetermined shape. The lead frame structure according to claim 1, wherein the outer lead is a surface mount type bent to a predetermined shape. The leadframe structure according to claim 1, wherein the rear lid is a BLP type. The leadframe structure as claimed in claim 1, wherein the outer lead and the inner lead are arranged in a zigzag form in which each other is arranged between each lead.