JPH0682665B2 - Method for manufacturing semiconductor device - Google Patents

Description

The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for manufacturing a semiconductor device having a wiring layer made of aluminum or aluminum alloy.

[Prior Art] FIG. 6 is a view showing a cross-sectional structure of an example of a conventional semiconductor device. In the figure, a PSG (phosphorus glass) film 2 is formed on a silicon substrate 1. On this PSG film 2,
The wiring layer 3 made of aluminum or aluminum alloy is formed. A final protective film 4 is formed on the wiring layer 3. For the final protective film 4, for example, phosphorus glass, silicon nitride, silicon oxide or the like is used.

FIG. 7 is a diagram showing a laminated structure of another example of the conventional semiconductor device. In the figure, a PSG film 2 is formed on a silicon substrate 1. A first wiring layer 5 made of aluminum or an aluminum alloy is formed on the PSG film 2. An interlayer insulating film 6 is formed on the first wiring layer 5.
Is formed. A second wiring layer 7 made of aluminum or an aluminum alloy is formed on the interlayer insulating film 6. The final protective film 4 is formed on the second wiring layer 7.

Next, a method of manufacturing the conventional semiconductor device shown in FIG. 6 will be described. Silicon substrate with an impurity diffusion layer 1,
An aluminum or aluminum alloy film 3 is formed on the entire surface of the PSG film 2 by sputtering or vacuum deposition.

Next, by using photolithography technology, patterning with a resist is performed, and an unnecessary portion of the aluminum or aluminum alloy film is removed by etching.
The wiring layer 3 having a desired shape is formed.

Then, in order to establish electrical contact between the wiring layer 3 and the silicon substrate 1, heat treatment at about 400 to 500 ° C. is applied, and finally, the final protective film 4 is formed.

[Problems to be Solved by the Invention] Since the conventional semiconductor device is configured as described above,
Hillocks are formed on the wiring layer 3 depending on the temperature during the formation of the wiring layer 3 and the heat treatment after the formation, or the temperature during the formation of the final protective film 4.
There is a problem in that abnormal protrusions of aluminum, which are referred to as "," cause pinholes in the final protective film 4 and deteriorate the moisture resistance of the semiconductor device. Further, in the semiconductor device having the multilayer wiring structure shown in FIG. 7, there is a problem that Hilllock generated on the first wiring layer 5 often causes interlayer insulation failure and reduces the yield.

As a method of suppressing the above-mentioned Hilllock, for example, as disclosed in JP-A-59-43549 or JP-A-59-99741, after patterning the aluminum wiring, the entire surface of the aluminum wiring is subjected to a plasma anodic oxidation method or hot water treatment. It is possible to form aluminum oxide on the surface of the aluminum wiring, but the aluminum natural oxide film formed in the patterning process and the dense aluminum oxide of about 100 Å formed by being exposed to O ₂ plasma in the photoresist removal process. Therefore, the formation of aluminum oxide by the above method is suppressed, and it is difficult to uniformly form an aluminum oxide film having a thickness of 1000 Å or more, which is necessary for suppressing Hillock, over the entire wiring layer.

The present invention has been made in order to solve the above problems, in which a Hilllock does not occur on a wiring layer made of aluminum or an aluminum alloy, and a semiconductor device having good moisture resistance and good interlayer insulation characteristics is provided. It is intended to provide a manufacturing method.

[Means for Solving Problems] A method of manufacturing a semiconductor device according to the present invention is a method for producing a surface in pure water or steam heated to a predetermined temperature or more immediately after forming an aluminum or aluminum alloy film to be a wiring layer. The aluminum or aluminum alloy film is treated to form an aluminum hydrate oxide layer on the surface of the aluminum or aluminum alloy film.

[Operation] Since the aluminum hydrated oxide layer formed on the wiring layer made of aluminum or aluminum alloy is extremely hard, it acts to prevent the growth of abnormal projections of the aluminum or aluminum alloy film forming the wiring layer. .

[Embodiment] FIG. 1 is a view showing a laminated structure of a semiconductor device according to an embodiment of the present invention. In the figure, on the silicon substrate 1,
The PSG film 2 is formed. A wiring layer 3 made of aluminum or an aluminum alloy is formed on the PSG film 2. An aluminum hydrated oxide layer 8 is formed on the wiring layer 3.
Is formed. A final protective film 4 is formed so as to cover the PSG film 2, the wiring layer 3 and the aluminum hydrated oxide layer 8.

FIG. 2 is a diagram showing a manufacturing process of the embodiment shown in FIG. The manufacturing method of the embodiment shown in FIG. 1 will be described below with reference to FIG.

Fig. 2 [I] Silicon substrate with impurity diffusion layer 1, PSG on it
A film 3 of aluminum or aluminum alloy is formed on the entire surface of the film 2 by sputtering or vacuum evaporation.

Fig. 2 [II] Aluminum or aluminum alloy film 3 immediately after film formation
The surface is treated with pure water or steam heated to 40 ° C. or higher to form an aluminum hydrated oxide layer 8 on the surface. The surface of the aluminum or aluminum alloy film 3 immediately after film formation is not sufficiently covered with a stable alumina layer and is relatively active. Therefore, an aluminum hydrated oxide layer 8 of 1000 Å or more can be easily formed by the above method. Can be obtained. This aluminum hydrated oxide layer 8 is a kind of alumina and is very hard and prevents the growth of abnormal projections in the aluminum or aluminum alloy film 3.

FIG. 3 shows the relationship between the thickness of the hydrated aluminum oxide layer 8 and the immersion time when immersed in pure water at 80 ° C.

FIG. 2 [III] Next, using a photomechanical technique, patterning with a resist 9 is performed to remove unnecessary portions of the aluminum hydrate oxide layer 8 and the aluminum or aluminum alloy film 3 by etching to obtain a desired shape. The wiring layer 3 having is formed.

2 [IV] After that, in order to establish electrical contact between the wiring layer 3 and the silicon substrate 1, heat treatment at about 400 to 500 ° C. is applied, and finally the final protective film 4 is formed.

The semiconductor device manufactured by the above method (see FIG. 1) has the aluminum hydrated oxide layer 8 and the wiring layer 3
Since the occurrence of the above-mentioned hilllock can be prevented, a pinhole is not formed in the final protective film 4, and a semiconductor device having good moisture resistance can be obtained.

Although the semiconductor device having the single-layer wiring structure has been described in the above embodiments, the present invention can be applied to the semiconductor device having the multilayer wiring structure. FIG. 4 is a diagram showing an example in which the present invention is applied to a semiconductor device having a two-layer wiring structure. In the figure, the structure of this embodiment is the same as that of the conventional example of FIG. 7 except for the following points. The feature of this embodiment is that the first
That is, the aluminum hydrated oxide layer 8 was formed on the wiring layer 5 by the method described above.

Further, as shown in FIG. 5, the aluminum hydrated oxide layer 8 may be formed not only on the first wiring layer 5 but also on the second wiring layer 7.

When the present invention is applied to a semiconductor device having a multilayer wiring structure as in the embodiment shown in FIGS. 4 and 5, the final protective film 4 is formed.
Not only can you prevent the occurrence of pinholes in the
It is also possible to prevent interlayer insulation failure due to, and it is possible to significantly improve the yield.

[Effects of the Invention] As described above, according to the present invention, the aluminum or aluminum alloy film to be the wiring layer is surface-treated immediately after the film formation in heated pure water or steam to form an aluminum solution on the wiring layer. Since the hydrated oxide layer is formed to prevent the occurrence of Hilllock on the wiring layer, it is possible to obtain a semiconductor device having good moisture resistance without pinholes in the final protective film.

[Brief description of drawings]

FIG. 1 is a diagram showing a laminated structure of a semiconductor device according to an embodiment of the present invention. FIG. 2 is a diagram showing a method of manufacturing the semiconductor device shown in FIG. FIG. 3 is experimental data showing the formation of a hydrated aluminum oxide layer. FIG. 4 and FIG. 5 are views showing a laminated structure of a semiconductor device according to another embodiment of the present invention. FIG. 6 is a diagram showing a cross-sectional structure of an example of a conventional semiconductor device. FIG. 7 is a diagram showing a laminated structure of another example of the conventional semiconductor device. In the figure, 1 is a silicon substrate, 2 is a PSG film, 3 is a wiring layer made of aluminum or an aluminum alloy, 4
Is a final protective film, 5 is a first wiring layer, 6 is an interlayer insulating film, 7
Is a second wiring layer, 8 is a hydrated aluminum oxide layer, and 9 is a resist. The same reference numerals in the drawings indicate the same or corresponding parts.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Reiji Tamaki Reiji Tamaki 4-1-1 Mizuhara, Itami-shi, Hyogo Mitsubishi Electric Corporation Kita-Itami Works (72) Takeshi Noguchi 4-1-1 Mizuhara, Itami-shi, Hyogo Mitsubishi Electric Corporation In the company Kita Itami Works (72) Inventor Junichi Arima 4-1-1 Mizuhara, Itami City, Hyogo Prefecture Mitsubishi Electric Co., Ltd. Kita Itami Works (56) Reference JP-A-52-61964 (JP, A)

Claims (2)

[Claims] 1. A method of manufacturing a semiconductor device having a wiring layer made of aluminum or an aluminum alloy, wherein pure water heated to a predetermined temperature or higher immediately after the formation of the aluminum or aluminum alloy film to be the wiring layer. A method of manufacturing a semiconductor device, comprising a step of performing a surface treatment in water vapor to form an aluminum hydrate oxide layer on the surface of the aluminum or aluminum alloy film. 2. The method for manufacturing a semiconductor device according to claim 1, wherein the predetermined temperature is approximately 40 ° C.