JP3223522B2 - Method for manufacturing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, and more particularly to a method of manufacturing a semiconductor device including a step of forming an organic silicate glass film as an interlayer insulating film.

[0002]

2. Description of the Related Art As semiconductor devices become more highly integrated and multi-layered,
Flattening an insulating film between wiring layers has become a very important issue. Since the organic silicate glass film by the coating method can easily form a thick film and has excellent flatness,
It is often used as a part of an interlayer insulating film of a metal multilayer wiring. Generally, a three-layer structure composed of a first oxide film, an organic silicate glass film, and a second oxide film is often used as this kind of interlayer insulating film.

However, if the second oxide film is formed on the organic silicate glass film as it is, the adhesion between the organic silicate glass film and the oxide film is extremely poor, and the second oxide film peels off. Therefore, there is a method in which oxygen plasma treatment is performed to make the surface of the organic silicate glass film inorganic to improve the adhesion.

A conventional forming method will be described with reference to the drawings.
FIG. 4 is a longitudinal sectional view of an example of a conventional forming method.

FIG. 4A shows that a first oxide film 44 is formed as an interlayer insulating film on an aluminum wiring 43 formed on an insulating film 42 on the surface of a semiconductor substrate 41, and an organic silicate glass film 45 is formed on the surface thereof. Is formed by a coating method. Heat treatment is performed to remove the solvent in the organic silicate glass film. Next, the silicate glass film 45
The inside is subjected to oxygen plasma treatment. As a result, the organic components in the organic silicate glass film 45 are removed, and the inorganic silicate glass film layer 46 is produced as shown in FIG.

[0006]

However, in the conventional method, since an organic silicate glass film is formed and subjected to an oxygen plasma treatment as it is after the heat treatment, not only the surface of the organic silicate glass film but also most of the surface is made inorganic. Would.
The mineralized silicate glass film thus generated is a porous film. The conventional method has a major disadvantage that cracks due to film shrinkage are liable to occur because the thickness of the porous layer is increased by the mineralization. Further, since a porous film has a strong hygroscopic property and easily contains moisture, a through hole is opened in an interlayer insulating film including such a silicate glass film, and when an upper wiring layer is formed, the silicate glass is not immersed. Has the disadvantage that the electrical properties of the through-holes are extremely poor due to the moisture.

An object of the present invention is to provide a film having almost the same adhesion to an oxide film as the conventional one, with little film shrinkage, preventing the occurrence of cracks, reducing the absorption of moisture, and preventing the deterioration of through-hole properties. An object of the present invention is to provide a method for forming a silicate glass film that can prevent the occurrence of a silicate glass film.

[0008]

According to a method of manufacturing a semiconductor device of the present invention, a step of forming an organic silicate glass film on a substrate surface by applying a solution containing silicon as a main component; Performing a plasma treatment with an inert gas to densify the surface of the organic silicate glass film, and subsequently performing an oxygen plasma treatment on the organic silicate glass film to mineralize the surface of the organic silicate glass film. And characterized in that:

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of a semiconductor substrate shown in the order of steps for explaining one embodiment of the present invention.

FIG. 1A shows a first oxide film 14 having a thickness of 0 μm as an interlayer insulating film on a 0.5 μm thick aluminum wiring layer 13 formed on an insulating film 12 on a semiconductor substrate surface 11. .4 μm.

Next, as shown in FIG. 1B, an organic silicate glass film 15 is formed on the surface. The organosilicate glass is a methyl group (-CH _3), a silicon oxide having a bond such as an ethyl group (-C ₂ H _5), is dissolved in a suitable organic solvent, it is formed by a coating method.
In order to remove the solvent after the formation, for example, 35
Heat treatment at 0 ° C. for 30 minutes. The surface of the thus formed organic silicate glass film 15 is substantially flat, and the film thickness is about 0.2 μ on the convex portion and about 0.7 μ on the other portions.

Next, in the present invention, as shown in FIG. 1C, a plasma treatment with argon (Ar) is performed. This plasma processing may be performed by, for example, a parallel plate type plasma processing apparatus as shown in FIG. That is, the semiconductor substrate 2 is placed on the high-frequency electrode 22 in the evacuated processing chamber 21.
Argon gas is supplied from the grounded counter electrode 24 to apply a high frequency to the semiconductor substrate 23. Here, when argon plasma processing is performed at a high frequency power of 600 W for 20 minutes, the surface of the organic silicate glass film 15 is densified. Next, as shown in FIG. 1D, an oxygen plasma treatment is performed to improve the adhesion when an oxide film is formed as an upper layer. This plasma treatment is performed in the same manner as in FIG.
May be performed continuously by the plasma processing apparatus. In this case, plasma treatment is performed at 300 W for 30 minutes. Alternatively, a barrel-type plasma processing apparatus may be used.

In the present invention, unlike the conventional method, since the surface of the organic silicate glass film 15 is densified by the argon plasma treatment, only about 0.05 μm of the surface of the organic silicate film is made inorganic even in the oxygen plasma treatment. Therefore, since the surface of the porous layer is about 0.05 μm, there is almost no film shrinkage due to the heat treatment, and the occurrence of cracks can be prevented. Further, there is almost no absorption of moisture, and deterioration of the through-hole property due to moisture can be prevented.

Thereafter, a second oxide film 17 is formed on the surface of the silicate glass film. This is usually the silane (S
H ₄ ), plasma CVD using nitrous oxide (N ₂ O)
Formed by the method, the surface 16 of the silicate glass film
Is an inorganic silicate glass film, so that good adhesion can be obtained, and the second oxide film 17 does not peel off.

In the second embodiment, after an organic silicate glass film is subjected to a plasma treatment using an inert gas, an oxygen plasma treatment is performed using a plasma CVD apparatus as shown in FIG. That is, the semiconductor substrate 33 is arranged on the grounded electrode 32 in the processing chamber 31 evacuated to vacuum, and the oxygen gas is made longer than the high-frequency electrode 34 arranged opposite.

The feature of the present embodiment is that the formation of the second oxide film after the oxygen plasma processing can be continuously performed by the same processing apparatus. Therefore, since it is not exposed to the atmosphere after the oxygen plasma treatment, absorption of moisture can be prevented more.

[0017]

As described above, according to the present invention, a porous inorganic silicate glass film is formed on a substrate surface, plasma treatment is performed with an inert gas, and then oxygen plasma treatment is performed. Since the formation of the silicate glass layer can be suppressed only on the surface, it has almost the same adhesion to the oxide film as before, but there is almost no film shrinkage, cracks are prevented, moisture absorption is reduced and through This has the effect that deterioration of the hole property can be prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view of a semiconductor substrate shown in the order of steps for explaining an embodiment of the present invention.

FIG. 2 is a schematic sectional view of a plasma processing apparatus used in one embodiment of the present invention.

FIG. 3 shows a plasma CVD used in a second embodiment of the present invention.
It is a schematic sectional drawing of an apparatus.

FIG. 4 is a cross-sectional view of a semiconductor substrate shown in a process order for explaining a conventional method of forming a silicate glass film.

[Explanation of symbols]

 11, 41 Semiconductor substrate 12, 42 Insulating film 13, 43 Aluminum wiring layer 14, 44 First oxide film 15, 45 Organic silicate glass film 16, 46 Vaporized silicate glass film 17, 47 Second oxide film 18 Argon plasma 19 49 Oxygen plasma 21 Processing chamber 22 High frequency electrode 23 Semiconductor substrate 24 Counter electrode 25 Vacuum pump 31 Processing chamber 32 Grounded electrode 33 Semiconductor substrate 34 High frequency electrode 35 Vacuum pump

Claims (3)

(57) [Claims] To 1. A substrate surface, forming an organosilicate glass film by a coating method of a solution composed mainly of silicon, the organosilicate glass facilities plasma treatment with inert gas into the organosilicate glass film Membrane table
A step of densification of the surface, followed by the organic silicon by subjecting the oxygen plasma treatment on the organosilicate glass film
The method of manufacturing a semiconductor device characterized by a step of mineralizing a surface of the questionnaire glass membrane. 2. The inert gas is an argon gas.
The method for manufacturing a semiconductor device according to claim 1, wherein: 3. The organic silicate gas whose surface is mineralized.
Forming an oxide film on the glass film.
3. The manufacturing of the semiconductor device according to claim 1, wherein
Method.