JPS63213362A - Resin sealed semiconductor device - Google Patents

Abstract

PURPOSE:To enable dispersion or relaxation of a stress generated in a semiconductor device, and obtain a stable quality wherein anti-stress properties are improved, by providing the whose rear of an island with an uneven surface or plural holes. CONSTITUTION:The whose rear of an island 3, on which a semiconductor element 2 is mounted, is provided with an uneven surface or a plurality of holes. Semiconductor sealing resin 6 is a solid at a room temperature, and turns into a liquid in a semiconductor sealing mold at a high temperature, so that it can easily penetrate into the inside of an unevenness 7 formed on the rear of the island 3. Accordingly, even if a shearing force or a tensile force generates between the rear surface of the island 3 and the semiconductor shielding resin 6 when the resin is solidified, the stress is dispersed by the wedge effect of the unevenness 7, and the breakdown of a bonding surface hardly generates. Thereby, the resistance against a thermal stress of the whole part of a semiconductor device 1 can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a resin-sealed semiconductor device, and particularly to improvements in lead frames used in the device.

[Conventional technology]

FIG. 4 is a sectional view showing a conventional resin-sealed semiconductor device. In the figure, 1 is a resin-sealed semiconductor device, 2 is a semiconductor element, which is bonded to an island 3, and is connected to an external lead 5 by an inner wire 4. electrically conductive. These materials are sealed with semiconductor sealing resin 6 and protected from the external environment. A lead frame for a semiconductor device is composed of an island 3 on which a semiconductor element 2 is mounted and held, an external lead 5, and an outer frame.

To manufacture a conventional lead frame, the semiconductor element 2 is mounted on the island 3, the semiconductor element 2 and the external leads 5 are electrically connected by the inner wire 4, and then,
It is molded and sealed and insulated with semiconductor sealing resin 6. This transfer molding is usually carried out at around 180°C. Semiconductor devices manufactured by the above process are generally made of materials having different coefficients of linear expansion. For example, when using 4270I as a semiconductor lead frame, its coefficient of linear thermal expansion is 3.5 x 10-6 /'C;
Semiconductor elements using silicon are 2.3 x 10-6
/l, and the semiconductor sealing resin is around 20×10″″6/′C.

[Problem that the invention seeks to solve]

Conventional resin-sealed semiconductor devices are configured as described above, so thermal stress is not applied to the semiconductor device, such as during cooling from transfer molding temperature to room temperature, mounting on a printed circuit board, or heat generation during operation of semiconductor elements. In this case, internal stresses such as compressive stress and shear stress occur in a semiconductor device made of composite materials having different coefficients of linear expansion in each material.

When internal stress occurs in a composite material, the stress applied to each material largely depends on the shape of each material and the adhesive force between each material. Among the materials that make up a semiconductor device, the adhesive force between the Guipad and the semiconductor encapsulating resin is weaker than the adhesive force between the semiconductor element and the semiconductor encapsulating resin, so the stress (shear stress and tensile stress) generated inside the semiconductor device due to temperature stress stress)
However, the bonding between the island and the semiconductor sealing resin is destroyed, and all the stress is concentrated at the lower end of the island, resulting in problems such as material failure and adhesive failure in some cases.
[Means for Solving the Problems] A resin-sealed semiconductor device according to the present invention has an uneven surface or a plurality of holes provided on the entire back surface of an island on which a semiconductor element is mounted.

[Effect]

In this invention, since an uneven surface or a plurality of holes are provided on the entire back surface of the island, the semiconductor encapsulating resin penetrates into the uneven step part or hole, and the biting effect causes generation between the island and the semiconductor encapsulating resin. By dispersing the shearing force and tensile force caused by the island, stress concentration at the island end can be avoided.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a resin-sealed semiconductor device according to an embodiment of the present invention. In the figure, 1 indicates a resin-sealed semiconductor device, and 2
is a semiconductor element, which is bonded to the island 3 and electrically connected to the external lead 5 through an inner wire 4.

These materials are sealed with semiconductor sealing resin 6 and protected from the external environment. Reference numeral 7 indicates unevenness provided on the back surface of the island. A lead frame for a semiconductor device is composed of an island 3 for mounting and holding a semiconductor element, external leads 5, and an outer frame. A lead frame for a semiconductor device in which a semiconductor element is mounted on an island 3 and the semiconductor element 2 and external leads 5 are electrically connected by an inner wire 4 is molded with a semiconductor sealing resin 6.

Sealed and insulated. This transfer molding is usually 18
It is carried out at around 0°C.

Next, the functions and effects of the device of this embodiment will be explained. The semiconductor encapsulation resin 6, which is solid at room temperature, becomes a liquid with a viscosity of several 10ocps in the high-temperature semiconductor encapsulation mold, and therefore easily penetrates into the inside of the unevenness 7 formed on the back surface of the island. Therefore, even if shearing force or tensile force is generated between the back surface of the island 3 and the semiconductor encapsulating resin 6 when the semiconductor encapsulating resin 6 is cured, the stress is dispersed due to the wedge effect of the unevenness 7. Breakage of the adhesive interface becomes less likely to occur.

In this implementation difference example, even if stress occurs inside the semiconductor device, the heat resistance of the entire semiconductor device is improved by improving the heat stress resistance between the back surface of the island and the semiconductor sealing resin, which was the weakest in the conventional structure. Stress resistance can be improved.

In the above example, the case where unevenness was formed on the back surface of the island was shown, but this is as shown in Fig. 2.
It may be a plurality of concave holes 8 whose opening diameter B is smaller than the internal diameter A, and in this case, as in the above embodiment, the back surface of the island 3 and the semiconductor sealing resin 6 are sheared in the lateral direction. Not only the resistance to stress is improved, but also the resistance to tensile stress in the longitudinal direction is improved, and the heat stress resistance can be improved.

In addition, instead of the unevenness of the above embodiment, a tapered shape (COD) in which the opening diameter increases in the depth direction as shown in FIG. 3 is used.
A plurality of through holes may be used, and the same effects as in the above embodiment can be achieved in this case as well.

〔Effect of the invention〕

As described above, according to the resin-sealed semiconductor device according to the present invention, since the uneven surface or the plurality of holes are provided on the entire back surface of the island, the internal stress generated at the interface between the back surface of the island and the semiconductor sealing resin is reduced. It can be mechanically reinforced and dispersed, making it possible to disperse or alleviate the stress that occurs inside semiconductor devices due to changes in the external environment, increasing stress resistance and providing stable quality. There is.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a resin-sealed semiconductor device according to an embodiment of the present invention, and FIGS. 2 and 3 are sectional views showing a resin-sealed semiconductor device according to another embodiment of the invention. FIG. 4 is a sectional view showing a conventional device. In the figure, 1 is a resin-sealed semiconductor device, 2 is a semiconductor element, 3 is an island, 4 is an inner wire, 5 is an external lead, 6 is a semiconductor sealing resin, 7 is an uneven surface of the back surface of the island 3, and 8 is an island 3 The hole 9 on the back side is a through hole on the back side of the island 3. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (3)

[Claims] (1) A frame-type resin-sealed semiconductor device in which a semiconductor element is resin-sealed in an island, characterized in that an uneven surface or a plurality of holes are formed on the back surface of the island. type semiconductor device. (2) The resin-sealed semiconductor device according to claim 1, wherein the plurality of holes are concave holes having an opening diameter smaller than an inner diameter thereof. (3) The resin-sealed semiconductor device according to claim 1, wherein the plurality of holes are tapered through holes whose opening diameter increases in the depth direction.