JPH05283558A - Resin-sealed semiconductor device - Google Patents

Abstract

PURPOSE:To buffer a stress from a lead frame to sealing resin by providing stress buffer film at corners to be formed at an island and a cut edge of a stitch of the frame. CONSTITUTION:A lead frame 1 is patterned in a predetermined shape by stamping with a press machine or etching a thin plate of nickel and iron alloy, copper material, etc. Corners 1a to be formed at front, rear and side faces of an island 2 to be placed with an integrated circuit chip and further front, rear and side faces of a stitch 3 to be bonded to the chip are covered with stress buffer films 5 in a range of a resin sealing region 4. Thus, after resin sealing, a stress generated due to a difference of thermal expansion coefficients between the frame 1 and sealing resin is alleviated by the film 5, and the stress is not applied directly to the resin, and hence a semiconductor device in which a crack can be prevented and which has high reliability can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-sealed semiconductor device, and more particularly to a lead frame for a semiconductor device.

[0002]

2. Description of the Related Art A lead frame of a conventional resin-encapsulated semiconductor device is a punching method by pressing a thin plate made of an alloy of nickel and iron, a copper material or the like with a die for forming a predetermined lead frame shape. Alternatively, a thin plate made of an alloy of nickel and iron, a copper material, or the like is covered with a mask material having a predetermined lead frame shape, and the lead frame is melted by an etching method to form the predetermined lead frame shape.

The island portion on which the integrated circuit chip of the lead frame of the resin-sealed semiconductor device by the pressing method or the etching method and the cut surface of the lead portion are formed at an angle of 90 ° with respect to the surface of the island on which the integrated circuit is mounted. It has the structure to have.

[0004]

In this conventional resin-encapsulated lead frame, when the temperature outside the semiconductor device rises or falls sharply after resin encapsulation, the coefficient of thermal expansion of the lead frame and the encapsulation resin is increased. The difference is that stress is applied to the encapsulating resin, and the encapsulating resin is cracked.

Therefore, there have been problems such as corrosion and short circuit of metal members due to infiltration of water into the semiconductor device.

An object of the present invention is to provide a resin-encapsulated semiconductor device in which the stress applied from the lead frame to the encapsulating resin is reduced to prevent the encapsulating resin from cracking.

[0007]

To achieve the above object, a resin-sealed semiconductor device according to the present invention has a stress buffer film and is connected to an integrated circuit chip and a stitch mounted on an island of a lead frame. A resin-encapsulated semiconductor device in which the bonded bonding wire is encapsulated with an encapsulating resin, wherein the stress buffer film is provided at a corner formed on the cut edge of the island and the stitch and encapsulated from the lead frame. It buffers the stress on the resin.

Further, the stress buffer film is provided over the entire resin sealing region excluding the island and the stitch.

[0009]

A stress buffer film such as a polyimide resin is provided on at least the surface of the lead frame on which the integrated circuit chip is mounted, the back surface and side surfaces thereof, the surface of the stitch portion where the bonding wires are connected, and the corners formed by the back and side surfaces thereof. The stress buffer film buffers the stress.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

(Embodiment 1) FIG. 1 is a plan view showing Embodiment 1 of the present invention, and FIG. 2 is a sectional view taken along the line AA 'in FIG.

In the figure, in a lead frame 1 in which a thin plate made of an alloy of nickel and iron or a copper material is punched by a press or patterned into a predetermined shape by etching, front and back surfaces and side surfaces of an island 2 on which an integrated circuit chip is mounted. Further, the corners 1a formed by the front and back surfaces and side surfaces of the stitch 3 bonded to the integrated circuit chip are covered with a stress buffer film 5 made of polyimide resin or the like within the resin sealing region 4.

With such a structure, the stress generated by the difference in the coefficient of thermal expansion between the lead frame 1 and the sealing resin after the resin sealing is alleviated by the stress buffer film 5, and the stress is not directly applied to the sealing resin. Absent.

(Embodiment 2) FIG. 3 is a plan view showing Embodiment 2 of the present invention, and FIG. 4 is a sectional view taken along the line BB 'in FIG.

In the first embodiment, only the corners 1a and side surfaces of the island 2 and the stitch 3 are covered with the stress buffer film 5.

In this embodiment, a stress buffer film 5'made of polyimide resin or the like is formed over the entire resin sealing region except the island 2 and the stitch 3.

Therefore, the contact portion between the encapsulating resin and the lead frame is minimized, the stress from the lead frame to the encapsulating resin is minimized, and the risk of resin cracking can be suppressed.

[0018]

As described above, according to the present invention, at least the surface of the lead frame on which the integrated circuit chip is mounted and its back surface and side surface, and the surface to which the bonding wire of the stitch portion is connected and its back surface and side surface are formed. By forming the stress buffer film on the core, the stress of the encapsulation resin due to the difference in the thermal expansion coefficient between the lead frame and the encapsulation resin is relieved by the stress buffer film, and the occurrence of cracks can be prevented. Can be provided.

[Brief description of drawings]

FIG. 1 is a plan view showing a first embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA ′ of FIG.

FIG. 3 is a plan view showing a second embodiment of the present invention.

FIG. 4 is a sectional view taken along line BB ′ of FIG.

[Explanation of symbols]

 1 Lead frame 2 Island 3 Stitch 4 Resin sealing area 5, 5'Stress buffer film

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H01L 23/50 G 9272-4M

Claims (2)

[Claims] 1. A resin-encapsulated semiconductor device having a stress buffer film, wherein an integrated circuit chip mounted on an island of a lead frame and a bonding wire connected to a stitch are encapsulated with an encapsulating resin. The resin-sealed semiconductor device, wherein the stress buffer film is provided at a corner formed on the cut edges of the island and the stitch and buffers the stress from the lead frame to the sealing resin. 2. The resin-encapsulated semiconductor device according to claim 1, wherein the stress buffer film is provided over the entire resin-encapsulated region excluding islands and stitches. And a resin-encapsulated semiconductor device.