JPH02291129A - Semiconductor device - Google Patents

Abstract

PURPOSE:To prevent a film quality from being deteriorated at a side part of a wiring part and to enhance a resistant property by a method wherein a passivating film is formed of an inorganic insulating film, an organic siloxane polymer and an inorganic insulating film in this order from the lower part so as to cover a metal wiring part of an uppermost layer which has been formed on a semiconductor substrate. CONSTITUTION:A PSG film 14 is grown on an Al wiring part 13 by a normal- pressure CVD operation; an organic siloxane polymer layer 15 is formed. That is to say, an alcohol solution of an organic siloxane polymer is spin-coated; a surface layer is oxidized by a plasma of O2; after that, a prescribed heat treatment is executed. Then, a silicon nitride film 16 is grown by a plasma CVD operation. A passivating film obtained in this manner can enhance a moisture-proof property and an electromigration-resistant property of a wiring part because its fragility, at a side part of a difference in level, which is inherent in a CVD film by the organic siloxane polymer is reinforced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a semiconductor device, and more particularly to a semiconductor device that has strong wiring electromigration resistance and moisture resistance.

[Conventional technology]

Conventional passivation films for semiconductor devices are made using plasma CVD.
A single layer of silicon nitride film (hereinafter referred to as P-SiN) grown by the method, or a PSG film 34 as shown in
It had a two-layer structure with P-SiN35 formed thereon.

[Problem to be solved by the invention]

In the conventional passivation film described above, due to the characteristics of the CVD film, the thickness of the film on the side of the wiring step becomes thinner and the film quality becomes brittle. This phenomenon becomes more noticeable as the wiring spacing becomes finer. That is, the CVD method is a chemical vapor phase reaction, and as the wiring spacing becomes fine, it becomes difficult to supply fresh reaction gas.

What happens because of this is that the moisture resistance, which is the original purpose of the passivation film, deteriorates. Furthermore, the electromigration resistance of the wiring running under the passivation film is reduced. To explain this in detail, when a current flows, compressive stress is generated within the wiring.

When the passivation film can no longer withstand this stress, cracks occur, causing bulges and whiskers in the wiring.
Elect4 migration will be accelerated. The maximum value of stress at this time is estimated to be approximately 1010 dyne/ct. This level of stress is originally a value that the CVD film can withstand, but because the film quality has deteriorated on the wiring side, it is no longer able to withstand this stress.

[Means to solve the problem]

According to the present invention, a semiconductor device is obtained in which the passivation film formed covering the uppermost layer of metal wiring formed on the semiconductor substrate is an inorganic insulating film, an organic siloxane polymer, and an inorganic insulating film in order from the bottom.

〔Example〕

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

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention.

Here, the element portion, wiring in layers lower than the top layer wiring, interlayer films, etc. are omitted. AA wiring 13" with a height of 1.0 μm and a PSG film 14 of 0.2 μm by atmospheric pressure CVD.
The organic siloxane polymer layer 15 is grown to a thickness of 0.5 .mu.m by the method disclosed in JP-A No. 63-266519. That is, an alcohol solution of an organic siloxane polymer is spin-coated and the surface layer is oxidized by 02 plasma.
Thereafter, heat treatment is performed at 400'C for 30 minutes. The film thickness is 0. The thickness was 2 μm to 0.5 μm. Next, a silicon nitride film 16 is grown to a thickness of 0.3 μm by plasma CVD. In order to investigate the electromigration suppressing effect of the passivation film thus obtained, the following experiment was conducted.

A height of 1. 0μm, width 8.0μm,
An Aj2 wiring having a length of 500 μm was formed, and the above passivation structure was formed thereon. This is called (A). For comparison, inorganic SOG (trade name OCD-Type 2) was used instead of the organic siloxane polymer in the structure of (A).
．． A level using 1 μm (B) and a level without an intermediate layer, that is, P-SiN/PSG (C) were also created. Assembled in ceramic package, 200℃, current density 2. OX106
An electromagnetization test was conducted under the conditions of A/cnt. The average failure time is (A) approximately 1000 hours, (
B) about 180 hours, (C) about 150 hours, which shows the effect of the wooden invention.

In order to investigate the moisture resistance of the passivation film, the following experiment was conducted on a PSG film with a phosphorus concentration of 10 mol%. 0/1. The above-mentioned passivation film structure was formed on a pattern in which several tens of 0 μm Afl wirings ran in parallel, and a molded package was assembled. 125
The PCT test was carried out under the conditions of 23 atm of °C and 100% of H20. The number of chips with disconnection defects after 30 hours is (A
)0 pcs/20 pcs (B) 2 pcs/20 pcs (C) 20 pcs/
It was 20.

This result shows that the passivation film of the present invention is highly effective in terms of moisture resistance.

FIG. 2 is a longitudinal sectional view of another embodiment of the invention.

Here, 0.2 μm to 10 μm is obtained by plasma CVD method.
An organic siloxane polymer layer (25) is applied to the formed SiON film (24) and then baked to a flat part thickness of 0.2
It was formed to a thickness of μ to 05μ. In this example, the SiON film 2
Since No. 4 has excellent moisture resistance, there is no need to form an inorganic insulating film on the organic siloxane polymer layer 25, and the number of steps can be reduced.

〔Effect of the invention〕

As explained above, in the present invention, the weakness inherent in the stepped side surfaces of the CVD film is reinforced by the organic siloxane polymer, so that it is possible to realize a semiconductor device with extremely excellent moisture resistance and wiring electromida- tion resistance. In particular, improvement in electromigration resistance can only be achieved by "flattening" using an organic siloxane polymer, since "smoothing" using inorganic SOG is insufficient.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view of a semiconductor device according to an embodiment of the present invention, FIG. 2 is a vertical sectional view showing another embodiment of the present invention, and FIG. 3 is for explaining problems of a conventional semiconductor device. FIG. 11,21.31...Semiconductor substrate, 12,22
, 32... Insulating film, 13, 23. 33...
A. C wiring, 14,34...PSG film, 15.25...
・Organosiloxane polymer layer, 16.35...Silicon nitride film, 36...Corrosion, 37...
・Crack, 24...SiON film. Agent Patent Attorney Susumu Uchihara

Claims (1)

[Claims] (1) A semiconductor device characterized in that the passivation film formed covering the uppermost layer of metal wiring formed on the semiconductor substrate is an inorganic insulating film, an organic siloxane polymer film, and an inorganic insulating film in order from the bottom (2). ) A semiconductor device characterized in that the passivation film formed covering the uppermost layer of metal wiring formed on the semiconductor substrate is an inorganic insulating film and an organic siloxane polymer film in order from the bottom.