JPH02271561A - Resin-sealed semiconductor device - Google Patents

Abstract

PURPOSE:To prevent a crack of a metal thin wire at a bonded part between an inner lead and the metal thin wire by a method wherein the inner lead is provided with recessed parts which have been formed on both side faces. CONSTITUTION:Recessed parts 3 are formed, in an asymmetric manner, on both side faces of inner leads 2 which have been arranged around an island 1 formed in the central part. Then, a semiconductor chip 4 is mounted on the island 1; electrodes of the semiconductor chip 4 and tip parts of the inner leads 2 are connected by metal thin wires 5. Then, the island 1 and the inner leads 2 are sealed with a resin body 6; a resin-sealed type semiconductor device is constituted. Thereby, when this device is mounted on a circuit board, it is possible to prevent a crack, of the metal thin wires, which is easily caused by a thermal stress exerted on bonded parts of inner leads.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a resin-sealed semiconductor device.

[Conventional technology]

A conventional resin-sealed semiconductor device is shown in FIG. 4(a).

As shown in (b), internal leads 2 are arranged and provided around the island 1, and a semiconductor chip 4 is placed on the island 1.
The electrodes of the semiconductor chip 4 and the internal leads 2 are connected by thin metal wires 5, and the island 1 and the internal leads 2 are mounted.
are sealed with a resin body 6.

[Problem to be solved by the invention]

In the conventional resin-sealed semiconductor device described above, the shape of the internal lead is almost linear, but in recent years, VSP (vapo
(rphase soldering) method and infrared reflow method have been adopted, but there is a problem in that this thermal stress causes cracks to occur at the joint between the thin metal wire and the internal lead, reducing reliability.

The crack generation mechanism is that the entire semiconductor is rapidly exposed to high temperatures of about 210°C to 260°C due to heating during board mounting, and the glass transition point of the resin body (160°C
(before and after) and the coefficient of thermal expansion of the resin increases rapidly, resulting in deformation of the resin.

As a result, the thin metal wires also move in the direction of expansion of the resin body and are deformed. However, since the thin metal wire is connected to the internal lead, stress is concentrated on the thin metal wire. Therefore, cracks occur at the weakest part of the thin metal wire.

[Means to solve the problem]

The resin-sealed semiconductor device of the present invention includes an island on which a semiconductor element is mounted, an internal lead provided around the island, a thin metal wire electrically connecting the semiconductor element and the internal lead, and a metal wire that electrically connects the semiconductor element and the internal lead. In a resin-sealed semiconductor device having a resin body that includes and seals the internal leads, the internal leads have recesses provided on both sides.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIGS. 1(a) and 1(b) are a partially cutaway plan view and a sectional view taken along the line AA', showing a first embodiment of the present invention.

As shown in FIGS. 1(a) and 1(b), the 0-order has recesses 3 asymmetrically provided on both sides of internal leads 2 arranged around an island 1 provided in the center. A semiconductor chip 4 is mounted on the island 1, and the electrodes of the semiconductor chip 4 and the tips of the internal leads 2 are connected by thin metal wires 5.Then, the island 1 and the internal leads 2 are sealed with a resin body 6. A resin-sealed semiconductor device is then constructed.

Next, an evaluation test was conducted using a conventional resin-sealed semiconductor device and a resin-sealed semiconductor device of the present invention, and the following results were obtained.

First, the resin-sealed semiconductor devices of the conventional and the present invention were subjected to temperature cycles (-60°C to +150'C) and humidification (85°C).
, 85%), and then we performed rapid heating mounting using the infrared reflow method (210°C to 260°C), which is a mounting method on a wiring board, and observed the joint between the thin metal wire and the internal lead. As a result, in the conventional technology, cracks occurred in the thin metal wire at the joint between the internal lead and the thin metal wire with a probability of about 80%, but with the present invention, the crack occurrence rate was able to be reduced to about 5%. .

FIG. 2 is a partially cutaway plan view showing a second embodiment of the present invention;
FIGS. 3(a) and 3(b) are an enlarged plan view and a sectional view taken along the line BB' of an internal lead according to a second embodiment of the present invention.

As shown in FIGS. 2 and 3 (a) and (b), the internal lead 2 is attached to both sides of the internal lead 2 from the bottom surface of the internal lead 2.
It has the same structure as the first embodiment except that recesses 3a are provided alternately on the left and right sides at a height of about 1/2 of the plate thickness of the first embodiment.
The strength of the internal lead is increased compared to the example of
This has the advantage that it is less likely to deform.

〔Effect of the invention〕

As explained above, the present invention provides recesses alternately on both sides of the internal leads arranged around the island on which the semiconductor chip is mounted, so that thermal stress is applied to the joints of the internal leads when mounted on a circuit board. This has the effect of preventing cracks in the thin metal wires that are likely to occur due to this, and improving the reliability of the semiconductor device.

[Brief explanation of drawings]

1(a) and (b) are a partially cutaway plan view and a sectional view taken along the line A-A' showing a first embodiment of the present invention, and FIG. 2 is a diagram showing a second embodiment of the present invention. Partial cutaway plan view, Fig. 3(a), (
b) is an enlarged plan view and a sectional view taken along the line B-B' of the internal lead of the second embodiment of the present invention, and FIGS. 4(a) and 4(b) show an example of a conventional resin-sealed semiconductor device. Partially cutaway plan view and c
It is a sectional view taken along the line -c'. DESCRIPTION OF SYMBOLS 1... Island, 2... Internal lead, 3... Recessed part, 4... Semiconductor chip, 5... Metal thin wire, 6...
-Resin body, 7...external lead.

Claims (1)

[Claims] An island on which a semiconductor element is mounted, an internal lead provided around the island, a thin metal wire that electrically connects the semiconductor element and the internal lead, and a resin body that includes and seals the island and the internal lead. 1. A resin-sealed semiconductor device having a resin-sealed semiconductor device, wherein the internal lead has recesses provided on both sides.