JPH0778910A - Semiconductor device - Google Patents

Abstract

PURPOSE:To provide a resin-sealed semiconductor device having a LOC structure, in which cracks are prevented from appearing in the molding resin behind the semiconductor chip. CONSTITUTION:By forming unevenness on the rear of a semiconductor chip 2, thermal stress operating between the rear of a semiconductor chip 2 and sealing resin 3 of a package is relieved, exfoliation is prevented, and generation of cracks of the sealing resin 3 of the package can be prevented.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Among conventional semiconductor devices, a resin-sealed semiconductor device is a semiconductor device in which a semiconductor chip is fixed and held on a metal called a die pad, and leads forming a terminal of the semiconductor device and a bonding pad on the semiconductor chip. And are connected by a bonding wire. FIG. 2 is a sectional view of an example of a conventional semiconductor device thus resin-sealed.
In FIG. 2, the semiconductor chip 2 is fixed and held on the die pad 1, and the leads 4 constituting the terminals of the semiconductor device and the bonding pads 5 provided on the surface of the semiconductor chip 2 are connected by the bonding wires 6. In this state, it is sealed with the sealing resin 3.

On the other hand, in contrast to such a conventional semiconductor device, a semiconductor device assembled by a new technology called LOC (abbreviation of Lead On Chip) has recently appeared. This eliminates the die pad 1 for fixing and holding the semiconductor chip 2 shown in FIG. 2 and fixes and holds the semiconductor chip 2 by the leads 4 themselves forming the terminals of the package. FIG. 3 shows a cross-sectional view of a semiconductor device assembled by a conventional LOC technique after resin sealing. The parts having the same functions as those of the conventional semiconductor device shown in FIG.

In FIG. 3, the semiconductor chip 2 is directly fixed to the lead 4 with an adhesive tape 8 via a polyimide layer 7. Here, the polyimide layer 7 is mainly used to protect the surface of the semiconductor chip 2. When this LOC technology is used, it is not necessary to separate the die pad from the leads, so that the semiconductor chip 2 which is larger than the conventional assembly technology by the size corresponding to the separation region is used.
Have the advantage that they can be assembled into a package of the same size. Further, since the lead 4 is arranged on the semiconductor chip 2, there is also an advantage that the degree of freedom in arranging the bonding pad 5 on the semiconductor chip 2 is increased by changing the shape thereof. For example, arranging the bonding pad 5 at the center of the semiconductor chip 2 also causes a problem that the bonding wire becomes long and contacts the semiconductor chip in the conventional technique.
Technology does not cause such problems.

[0005]

However, the conventional LO
In the semiconductor device having the C structure, damage such as cracks may occur in the sealing resin below the semiconductor chip. This problem will be described in detail below.

When the semiconductor device is subjected to thermal stress such as being kept at a high temperature, the contact surface of the semiconductor chip and the sealing resin on the back surface and the polyimide layer on the front surface and the leads differ in thermal expansion coefficient. Thermal stress occurs. Then, due to this stress, peeling occurs on the contact surface, water contained in the sealing resin comes out in this gap and is vaporized, and when the vapor pressure becomes large, damage such as cracks occurs in the sealing resin. On the surface side of the semiconductor chip, the leads are arranged intricately on the surface of the semiconductor chip, so that the thermal stress is appropriately dispersed and the adhesion with the sealing resin is improved. On the other hand, the back surface of the semiconductor chip has a flat surface that comes into contact with the sealing resin over a large area, so that peeling of the contact surface is likely to occur. Moreover, most of the semiconductor devices using the LOC technology have a large pellet area, the distance from the end of the pellet to the side wall of the package is small, and damage such as cracks is likely to occur due to the sealing resin.

Therefore, an object of the present invention is to solve the above problems and to provide a semiconductor device which holds a semiconductor chip and can prevent damage such as cracks in a sealing resin.

[0008]

SUMMARY OF THE INVENTION The present invention provides a semiconductor device in which the semiconductor chip is fixed to the leads by means of a means for adhering the surface of the semiconductor chip to the leads of the package and resin-sealed. The back surface of the has unevenness.

[0009]

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

FIG. 1 is a sectional view of a semiconductor device showing an embodiment of the present invention. In FIG. 1, the semiconductor chip 2 has a polyimide layer 7 applied on the semiconductor chip 2,
It is fixed to the lead 4 with an adhesive tape 8. The difference from the conventional semiconductor device shown in FIG. 3 is that unevenness is provided on the back surface of the semiconductor chip. In this way, by providing unevenness on the back surface of the semiconductor chip 2, the contact area between the back surface of the semiconductor chip 2 and the sealing resin 3 increases, the adhesiveness with the sealing resin 3 is improved, and peeling due to thermal stress can be prevented. it can.
As a means for providing the back surface of the semiconductor chip 2 with unevenness, a method of intentionally providing the unevenness when the back surface of the semiconductor wafer is ground to reduce the wafer thickness is considered.

[0011]

As described above, according to the present invention, in the semiconductor device in which the semiconductor chip is fixed to the lead by means of the means for adhering the surface of the semiconductor chip to the lead of the package and resin-sealed, the back surface of the semiconductor chip By providing unevenness on the
This has an effect of preventing the sealing resin of the package, which is in contact with the back surface of the semiconductor chip, from being damaged by thermal stress such as cracks.

[Brief description of drawings]

FIG. 1 is a sectional view of a semiconductor device showing an embodiment of the present invention.

FIG. 2 is a sectional view of an example of a conventional semiconductor device sealed with a resin.

FIG. 3 is a cross-sectional view of a semiconductor device assembled by a conventional LOC technique after resin sealing.

[Explanation of symbols]

 1 Die Pad 2 Semiconductor Chip 3 Sealing Resin 4 Lead 5 Bonding Pad 6 Bonding Wire 7 Polyimide Layer 8 Adhesive Tape

Claims (1)

[Claims] 1. In a semiconductor device in which the semiconductor chip is fixed to the lead by means of bonding the surface of the semiconductor chip to a lead of a package and resin-encapsulated, unevenness is provided on the back surface of the semiconductor chip. A semiconductor device characterized by: