JP2002026192A - Lead frame - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lead frame which is used for the manufacture of an individual molding type resin-sealed semiconductor device and can prevent thin resin burrs from being produced on the surfaces of the terminals of the lead frame, when a semiconductor element is molded. SOLUTION: This lead frame is one, which is used for manufacturing a resin-sealed semiconductor device using a method, where a semiconductor element 4 is mounted on a die pad 3 supported by suspension leads of the lead frame. After terminal parts 5 of the lead frame are electrically connected with electrodes on the upper surface of the element 4 through metal thin wires 6, the element 4 is molded and thereafter, the element 4 is punched into the individual semiconductor device by a metal mold. The terminal parts 5 of the lead frame are bent downward and are made to incline. When the metal mold is set into molding forces 11 and 12, the degree of adhesive strength of the terminal parts 5 with respect to the molding force 11 is increased by a spring action. As a molding resin is prevented from entering the back sides of the terminal parts 5, the generation of thin resin burrs on the rears of the terminal parts 5 is reduced, and proper solderability at mounting of a substrate on the lead frame can be ensured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of a resin-encapsulated semiconductor device in which a semiconductor element is mounted on a lead frame and an outer periphery thereof, particularly, an upper surface side of the semiconductor element is sealed with a mold resin. It is.

[0002]

2. Description of the Related Art In recent years, with the increase in the density of substrate mounting, there has been a demand for smaller and thinner semiconductor products mounted on the substrate. LSIs are also strictly required to reduce the number of chips and reduce the size and weight of packages due to high integration.
(Chip Size Package) is spreading rapidly. In particular, in the development of thin semiconductor products using a lead frame, a single-sided resin-sealed semiconductor device in which a semiconductor element is mounted on a lead frame and the mounting surface is sealed with a mold resin has been developed. I have.

FIG. 1 is a cross-sectional view showing an example of a resin-sealed semiconductor device, and FIG. 2 is a plan view showing the sealing resin as seen through. The resin-encapsulated semiconductor device shown in these figures includes a semiconductor element 4 mounted on a die pad 3 supported by suspension leads 2 of a lead frame 1, an electrode on the upper surface of the semiconductor element 4, and a terminal of the lead frame 1. A thin metal wire 6 electrically connected to the portion 5, and a sealing resin 7 for sealing an area surrounding the semiconductor element 4 including the upper side of the semiconductor element 4 and the lower side of the die pad 3 are provided. This resin-encapsulated semiconductor device is a non-lead type in which a so-called outer lead does not protrude, and both an inner lead and an outer lead are integrated as a terminal portion 5. The lead frame 1 used is half-etched so that the die pad 3 is located above the terminal portion. By forming such a step, the die pad 3
The sealing resin 7 can be made to exist also on the lower side, and a thin type can be realized even if the die pad is not exposed.

In the above-described non-lead type resin-encapsulated semiconductor device, since the size of a semiconductor element is small, a matrix type manufactured by arranging a plurality of rows in the width direction of one frame is mainly used. . And recently,
Due to cost reduction requirements, it has been considered to shift from the individually molded type as shown in FIG. 3 to the collectively molded type as shown in FIG.

In the individual mold type, as shown in FIG. 3A, small mold cavities C of a small size are provided in one frame F in a divided state.
After the molding, the semiconductor device S shown in FIG. That is, a semiconductor element is mounted on a die pad of a lead frame using silver paste or the like, and after performing wire bonding, individual semiconductor elements are individually molded and then punched out as individual semiconductor devices using a mold.

In the collective mold type, as shown in FIG. 4A, several large-sized mold cavities C are provided in one frame F. After arranging a large number of semiconductor elements in a matrix and molding the semiconductor elements collectively, the portions of the grid leads L of each lead frame are cut with a dicing saw to obtain a semiconductor device S shown in FIG. What you get. That is, a semiconductor element is mounted on a die pad of a lead frame using a silver paste or the like, and after performing wire bonding, a plurality of semiconductor elements are collectively molded with a predetermined cavity size, and then singulated by dicing. You do it.

[0007]

In the manufacturing process of the above-described resin-encapsulated semiconductor device, after the resin is molded, the resin wraps around the back surface of the terminal portion to generate thin burrs. In order to ensure the properties, thin burrs of the resin are removed by a water jet or a laser. Alternatively, a resin sheet is laid on the terminal surface during molding to prevent occurrence of burrs.

However, the former method has a problem that it is difficult to completely remove the thin burrs of the resin, and even if it is possible, it takes time. In the latter case,
In particular, in the case of the collective mold type, the press at the time of molding is weak, and the resin flows around, so that the burr could not be completely eliminated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a lead frame used particularly for manufacturing an individually molded type resin-sealed semiconductor device. An object of the present invention is to provide a lead frame capable of preventing thin resin burrs from being generated on a terminal surface during molding.

[0010]

In order to achieve the above object, a lead frame according to the present invention has a semiconductor element mounted on a die pad supported by suspension leads, and has a terminal portion connected to an electrode on the upper surface of the semiconductor element and a thin metal wire. A lead frame used for manufacturing a resin-encapsulated semiconductor device by molding a semiconductor element and then punching the individual semiconductor device with a mold after electrically connecting the terminals, with the terminal portion facing downward. It is characterized by being bent and inclined.

[0011]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 5 shows an example of a lead frame according to the present invention. FIG. 5A is a plan view, and FIG.
It is XX sectional drawing of (A).

As shown in the figure, a lead frame 1 supports a die pad 3 with four suspension leads 2 from the periphery.
Four terminal portions 5 protrude from the surrounding four sides toward the die pad 3. Each terminal portion 5 is bent at the base of the terminal portion 5 and is inclined downward. That is, a downward inclination is provided at a slight angle by bending the tip by machining. Normally, a plurality of such lead frames 1 are arranged in a single frame.

A procedure for manufacturing a resin-encapsulated semiconductor device using the lead frame 1 is as follows. First, a semiconductor element is mounted on a die pad 3 supported by a suspension lead 2 in a lead frame 1 with a silver paste,
After performing wire bonding between the terminal portion 5 and the electrode on the upper surface of the semiconductor element, the semiconductor device is set in a mold and individually molded, and then punched into individual semiconductor devices by a mold.

FIG. 6 is an explanatory diagram of a molding step when the lead frame shown in FIG. 5 is used. As shown in the figure, a lead frame 1 on which a semiconductor element 4 is mounted and wire bonding with a thin metal wire 6 is completed is replaced with a lower mold 1 of a mold type.
1 and set so as to cover the upper mold 12 from above. In this case, in a state where the lead frame 1 is placed on the lower mold 11, the whole is slightly floated due to the inclination of the terminal portion 5. However, by covering the upper mold 12, a peripheral portion of the lead frame 1 is pressed, The terminal portion 5 is straightened along the surface of the lower mold 11, and the terminal portion 5 is pressed against the surface of the lower mold 11 by the force of a spring and comes into close contact with the lower mold 11. Therefore, when molding is performed in this state, it is possible to prevent the resin from entering the back side of the terminal portion 5 and to eliminate or reduce the occurrence of burrs.

[0016]

As described above, in the lead frame of the present invention, the semiconductor element is mounted on the die pad supported by the suspension lead, and the terminal portion is electrically connected to the electrode on the upper surface of the semiconductor element by the thin metal wire. A lead frame used for manufacturing a resin-encapsulated semiconductor device by molding a semiconductor element and then punching it into individual semiconductor devices with a mold, wherein a terminal portion is bent downward and inclined. When set in the mold, the degree of adhesion of the terminal to the mold increases due to the action of the spring when the mold is set in the mold, preventing the mold resin from entering the back of the terminal. The occurrence of thin burrs is reduced, and a good solder plating property at the time of mounting can be ensured without performing the deburring step conventionally performed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of a resin-sealed semiconductor device.

FIG. 2 is a plan view of the resin-sealed semiconductor device shown in FIG.

FIG. 3 is an explanatory diagram of an individual mold type.

FIG. 4 is an explanatory view of a collective mold type.

5A is a plan view showing an example of a lead frame according to the present invention, and FIG. 5B is a cross-sectional view taken along line XX of FIG. 5A.

FIG. 6 is an explanatory diagram of a molding step when the lead frame shown in FIG. 5 is used.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lead frame 2 Suspended lead 3 Die pad 4 Semiconductor element 5 Terminal part 6 Thin metal wire 7 Sealing resin 11 Lower mold 12 Upper mold

Claims (1)

[Claims] 1. A semiconductor device is mounted on a die pad supported by a suspension lead, and a terminal portion is electrically connected to an electrode on an upper surface of the semiconductor device by a thin metal wire. A lead frame used for manufacturing a resin-encapsulated semiconductor device by punching out a semiconductor device according to (1), wherein the terminal portion is bent downward to be inclined.