JPH0541377A - Semiconductor device - Google Patents

Abstract

PURPOSE:To restrain a stress, in the transverse direction, which is exerted on metal wiring in a stepped part and to prevent the crack of a passivation film and the dislocation of the metal wiring by a method wherein at least one stepped part is formed under the metal wiring in the peripheral part of a pellet where the stress is concentrated largely. CONSTITUTION:A field oxide film 3 which is formed on a semiconductor substrate 2 is not formed locally. Thereby, a recessed part is formed. Metal wiring 1 such as power-supply by the recessed part. A dislocation stress, in the transverse direction, which is caused in the interface between a resin and a semiconductor pellet can be supported by the recessed part. Thereby, it is possible to prevent a crack from being produced in a passivation film 5 and to prevent the metal wiring 1 from being dislocated. Consequently, the reliability of a semiconductor device can be improved. For example, metal wiring can be formed in a peripheral part within 400mum from the corner part of a pellet and within 100mum from the side of the pellet, and the area effect of the semiconductor pellet can be improved.

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 the structure of a metal wiring portion arranged around a semiconductor pellet.

[0002]

2. Description of the Related Art In a conventional semiconductor device, as shown in FIG. 3, metal wiring is often arranged in a flat portion in which a plurality of interlayer insulating films are laminated on a thick field oxide film 23 formed by the LOCOS method. In particular, the bus lines of signal lines arranged in the peripheral portion of the semiconductor pellet, the metal wiring used as the power supply line and the GND line intersect with the lead-in lines of the polysilicon wiring and the silicide wiring which are the input / output lines of the circuit block. Other than that, it was arranged on a flat portion with no unevenness on the base.

On the metal wiring, SiO is used for protecting the wiring from physical impact and chemical corrosion due to invasion of moisture.
A passivation film 24 formed of ₂ , PSG film, Si ₃ N ₄ film SiON, or the like is provided.

[0004]

In this conventional semiconductor device, when assembled in a mold package, when a temperature cycle test is carried out to check the resistance to ambient temperature changes, the passivation film is thermally expanded by the encapsulating resin and the semiconductor pellet. Due to different rates, the stress generated at the interface between the encapsulating resin and the semiconductor pellets due to temperature changes caused cracks in the passivation film at the pellet corners and pellet periphery, which led to a decrease in moisture resistance. . In the worst case, there was a defect that the metal wiring was displaced.

This defect becomes more remarkable as the pellet size becomes larger as the degree of integration is improved, and the reliability is deteriorated, or the metal wiring cannot be arranged at the pellet corner portion or the peripheral portion. It was

For example, the pellet size is 6 μm × 15 μm
In this case, since the metal wiring cannot be arranged within 400 μm from the pellet corner portion and within 100 μm from the side of the pellet, there is a problem that the area efficiency of the semiconductor pellet is not good.

[0007]

According to the present invention, in a semiconductor device having a metal wiring provided on an insulating film of a semiconductor pellet and a passivation film covering the metal wiring, the metal in the peripheral portion of the semiconductor pellet is provided. It is said that a step is provided below the wiring.

[0008]

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

FIG. 1 is a sectional view of a semiconductor pellet according to the first embodiment of the present invention. 1 is metal wiring, 2 is a semiconductor substrate,
3 is a field oxide film, 4 is an interlayer film, and 5 is a passivation film.

In this embodiment, the field oxide film 3 formed on the semiconductor substrate 2 is not locally formed to form a recess, and the metal wiring 1 such as a power supply wiring is formed on the step formed by the recess. I am doing it. By receiving the lateral displacement stress generated at the interface between the resin and the semiconductor pellet at the step portion, it is possible to prevent cracking of the passivation film 5 and further prevent the displacement of the metal wiring 1. Therefore, the reliability of the semiconductor device can be improved. Alternatively, it is possible to provide metal wiring within 400 μm from the corner portion of the pellet and within 100 μm from the side of the pellet, thereby improving the area efficiency of the semiconductor pellet.

The above-mentioned recess may be a groove having a width of about half the width of the metal wiring 1 and extending along the metal wiring, but it is not always required to be a continuous groove.

FIG. 2 is a sectional view of a semiconductor pellet according to the second embodiment of the present invention. Reference numeral 11 is a metal wiring, 12 is a semiconductor substrate, 13 is a field oxide film, 14 is an interlayer film, 15 is a passivation film, and 16 is a polycrystalline silicon film.

In this embodiment, a polycrystalline silicon film 13 having a thickness of about 0.2 μm, which is narrower than the metal wiring 11 is formed on the semiconductor substrate 12, and the metal wiring 1 is formed so as to cover the polycrystalline silicon film 13.
1 is formed. By the step due to the step due to the polycrystalline silicon film 13, the lateral stress generated at the interface between the resin and the pellet is received at the step, so that the crack of the passivation film can be prevented and the deviation of the metal wiring 11 can be prevented. Further, instead of the polycrystalline silicon film 13, an insulating film may be used as long as it is provided in the lower layer of the metal wiring 11.

[0014]

As described above, according to the present invention, by providing at least one step below the metal wiring around the pellet where the stress concentration is large, the lateral stress applied to the metal wiring at the step is suppressed. Therefore, it is possible to prevent cracks in the passivation film, deviations in the metal wiring, etc., and it is possible to improve the area efficiency of the semiconductor pellet or the reliability of the semiconductor device.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of the present invention.

FIG. 2 is a sectional view showing a second embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a conventional example.

[Explanation of symbols]

 1,11,21 Metal wiring 2,12,22 Semiconductor substrate 3,13,23 Field oxide film 4,14 Interlayer film 5,15,24 Passivation film 16 Polycrystalline silicon film

Claims (2)

[Claims] 1. A semiconductor device having a metal wiring provided on an insulating film of a semiconductor pellet and a passivation film covering the metal wiring, wherein a step is provided below the metal wiring in a peripheral portion of the semiconductor pellet. A semiconductor device characterized by the above. 2. The semiconductor device according to claim 1, wherein the metal wiring is provided so as to cover the step portion formed by the concave portion locally formed in the field oxide film.