JPH098137A - Semiconductor device and manufacturing method thereof - Google Patents

Abstract

(57) [Abstract] [Purpose] To prevent deterioration of element characteristics due to diffusion of water from the SOG film used as an interlayer insulating film into the inside of the device. [Structure] CVD oxide film 14 formed on metal wiring 13
An insulating film 15 made of amorphous silicon or polycrystalline silicon is formed on the above. On top of that, SOG for step reduction
A film 16 is formed by coating, and a CVD oxide film 17 is further formed thereon to form an interlayer insulating film having a multilayer structure. [Effect] The insulating film 15 made of amorphous silicon or polycrystalline silicon serves as a moisture barrier film, and prevents moisture from the SOG film 16 from diffusing into the inside of the device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device having a wiring layer and an interlayer insulating film formed on the wiring layer and a method for manufacturing the same, and more particularly to a semiconductor device having a multilayer wiring structure and a method for manufacturing the same. It is particularly suitable for application.

[0002]

2. Description of the Related Art Conventionally, TEOS (tetraethyl orthosilicat
A film formed by plasma CVD using e) as a raw material, and a liquid coating film such as SOG (spin-on-glass) for alleviating a step difference are used.

FIG. 2 shows a conventional method of manufacturing a semiconductor device.

As shown in FIG. 2A, the semiconductor substrate 21
After the oxide film 22 is formed thereon by the atmospheric pressure CVD method or the like, the metal film 23 is formed by the sputtering method. Then, the metal film 23 is patterned by photolithography and dry etching to form the wiring layer 23. After that, the insulating film 24 is formed by the plasma CVD method using TEOS.

Since the insulating film 24 formed by this plasma CVD method has a poor step coverage, if the next wiring layer is formed directly thereon, the depth of focus of the wiring layer by photolithography becomes insufficient, or dry etching is performed. Sometimes the wiring is short-circuited at the lower part of the step, so it is necessary to reduce the step.

Therefore, as shown in FIG. 2B, a liquid coating film 25 of SOG or the like is formed on the insulating film 24 by spin coating to alleviate the step. After that, the liquid coating film 25 is annealed and, if necessary, an extra liquid coating film 2 is added.
Etch back 5. After that, the insulating film 26 is formed by the plasma CVD method using TEOS, and the insulating film 2 is formed.
4. An interlayer insulating film including the liquid coating film 25 and the insulating film 26 is formed.

After that, as shown in FIG. 2C, a metal film 27 is formed by a sputtering method, and the metal film 27 is patterned by a photolithography technique and dry etching to form a wiring layer 27.
To form After that, if necessary, the protective film 28 is covered with PS.
It is formed of G (phospho-silicate glass), plasma SiN, or the like.

[0008]

However, in the above-mentioned conventional structure, since the liquid coating film 25 itself is a film containing water, various heat treatment steps performed after the liquid coating film 25 is formed, or During operation of the semiconductor device, there is a problem that water in the liquid coating film 25 diffuses inside the semiconductor device and deteriorates, for example, transistor characteristics, resulting in a semiconductor device having low reliability.

The liquid coating film 25 generally loses water content when a high temperature of about 700 ° C. is applied, but since most of the multilayer wiring structure is wiring made of Al, such high temperature treatment is not possible. It was difficult.

Therefore, an object of the present invention is to provide a highly reliable semiconductor device capable of preventing moisture in a liquid coating film from diffusing into the semiconductor device and a method for manufacturing the same.

[0011]

In order to solve the above-mentioned problems, a method of manufacturing a semiconductor device according to the present invention is a method of manufacturing a semiconductor device in which an interlayer insulating film is formed on a semiconductor substrate having a wiring layer, Forming a first insulating film on the wiring layer; forming a second insulating film made of amorphous silicon or polycrystalline silicon on the first insulating film; The method includes a step of applying a liquid material on the second insulating film to form a third insulating film, and a step of forming a fourth insulating film on the third insulating film.

The semiconductor device of the present invention is a semiconductor device having a wiring layer and an interlayer insulating film formed on the wiring layer, wherein the interlayer insulating film is at least a first insulating film formed by coating. A layer, and a second insulating film layer made of amorphous silicon or polycrystalline silicon between the first insulating film layer and the wiring layer.

[0013]

In the present invention, an insulating film made of amorphous silicon or polycrystalline silicon is provided between the coating forming film used for the interlayer insulating film and the wiring layer thereunder in order to reduce the step, and the coating is performed. It prevents the moisture from the formed film from diffusing into the inside of the device.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention will be described below with reference to FIG.

First, as shown in FIG. 1A, a silicon oxide film 12 having a thickness of 500 to 1000 nm is formed on a silicon semiconductor substrate 11 by an atmospheric pressure CVD method, and then a metal film 13 made of Al or an Al alloy is formed. Thickness 400 by sputtering method
A film is formed up to 600 nm. After that, the metal film 13 is patterned by photolithography and dry etching,
The wiring layer 13 is formed. After that, the insulating film 14 is formed to a thickness of 200 to 400 nm by the plasma CVD method using TEOS.

Next, as shown in FIG. 1B, an amorphous silicon film 15 is formed to a thickness of 50 to 150 nm by a sputtering method.

Next, as shown in FIG. 1C, a liquid coating film 16 such as SOG is spin-coated on the amorphous silicon film 15 to form a film having a thickness of 100 to 1000 nm, and a step is formed. ease. Then, the liquid coating film 16 is set to 400 to 45.
Annealing is performed at 0 ° C., and excess liquid coating film 16 is etched back if necessary. After that, the insulating film 17 is formed by the plasma CVD method using TEOS at 400 to 600.
An interlayer insulating film having a laminated structure of the CVD insulating film 14, the amorphous silicon film 15, the liquid coating film 16 and the CVD insulating film 17 is formed to a film thickness of nm.

Thereafter, as shown in FIG. 1D, a metal film 18 made of Al or an Al alloy is formed by sputtering to a thickness of 600 to 600 nm.
A film having a thickness of 900 nm is formed and patterned by a photolithography technique and dry etching to form the wiring layer 18. After that, the protective film 28 is formed with PSG or plasma SiN to a film thickness of 400 to 1500 nm, if necessary.

As described above, in the structure of this embodiment, since the amorphous silicon film 15 is formed as the moisture barrier film under the liquid coating film 16, it is used in various heat treatments or in the subsequent apparatus. The water from the liquid coating film 16 is effectively prevented from diffusing into the inside of the device during the operation of, and as a result,
Since the transistor characteristics are not deteriorated, the reliability of the semiconductor device is improved.

As the moisture barrier film, a polycrystalline silicon film may be used instead of the amorphous silicon film 15 of the above-mentioned embodiment.

[0021]

According to the present invention, it is possible to effectively prevent the moisture from the liquid coating film used for the interlayer insulating film from diffusing into the inside of the device in order to reduce the step. The deterioration of the characteristics is prevented, and the reliability of the semiconductor device is improved.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a method of manufacturing a semiconductor device according to an embodiment of the present invention in the order of steps.

FIG. 2 is a schematic cross-sectional view showing a method of manufacturing a conventional semiconductor device in the order of steps.

[Explanation of symbols]

 11 Silicon Semiconductor Substrate 12 Insulating Film 13 Wiring Layer 14 Insulating Film 15 Amorphous Silicon Film 16 Liquid Coating Film 17 Insulating Film 18 Wiring Layer 19 Protective Film

Claims (2)

[Claims] 1. A method of manufacturing a semiconductor device in which an interlayer insulating film is formed on a semiconductor substrate having a wiring layer, the method comprising: forming a first insulating film on the wiring layer; A step of forming a second insulating film made of amorphous silicon or polycrystalline silicon on the first insulating film, and a step of forming a third insulating film by applying a liquid material on the second insulating film And a step of forming a fourth insulating film on the third insulating film, the method of manufacturing a semiconductor device. 2. A semiconductor device having a wiring layer and an interlayer insulating film formed on the wiring layer, wherein the interlayer insulating film is at least a first insulating film layer formed by coating and the first insulating film layer. A semiconductor device having a second insulating film layer made of amorphous silicon or polycrystalline silicon between the insulating film layer and the wiring layer.