JPS593853B2 - Method for manufacturing semiconductor devices - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a semiconductor device, and an object of the present invention is to provide a method of manufacturing a semiconductor device with improved electrode wiring.

Conventionally, in the manufacture of semiconductor devices, a wiring layer is formed on a semiconductor element (hereinafter abbreviated as an element) and then an electrical insulating film (hereinafter abbreviated as an insulating film) is laminated and deposited, or an insulating film is applied after a wiring layer is formed. In the case of laminated deposition, low temperature oxidation method (CVD method: Chemical
SiO2 film by V&porDeposition),
Coating SiO2 is coated with spin-on silica (Spin
A SiO2 film formed by onSilica) was applied.

Next, the above is illustrated in FIGS. 1 a to i.
In the manufacturing process of the Mosn layer shown in FIG.

Next, the SiO2 film 2 is etched to form openings 2a and 2a'.
■) (Figure b). P-type impurities such as boron are diffused into the openings to form source and drain P-type regions 3.
, 3' (Figure c). Next, after forming a SiO2 film (FIG. c), the SiO2 film is removed to form a gate portion (FIG. d). The SiO2 film removed portion is mainly made of SiO
A second gate oxide film 4 is formed (Fig. e). Next, after openings 3a and 3a' are formed to expose a part of the source and drain regions 3, 3' and 10 (Fig. f), an aluminum layer 5 as a wiring metal layer is deposited (Fig. g). ), and then a photoresist layer 6 for etching is further laminated and deposited.■
) (figure). The resist layer 6 is formed into a predetermined pattern (FIG. 15i), and using this as a mask, the aluminum layer 5 is etched (FIG. 15j). 5' in figure j,
, 5"' is the remaining aluminum layer and serves as an electrode metal layer. In the MOSIC as described above, since the MOS transistors are separated by the SiO2 film 2, parasitic moss is generated.

Therefore, in order to prevent the generation of this parasitic moss, the thickness of the SiO2 film 2 is 1.5 to 2.5μ, and the gate oxide film 4 has a small thickness of 200σA.
There is a large step between the two films 25. (Figure 2). If an aluminum layer with a thickness of 1.0 to 1.5 μm is deposited on the top surface, the step portion will be less than 0.5 μm. Due to poor adhesion to the photosensitive resin in the 30th area, the etching solution penetrates, creating a narrowed area 5a as shown by the dotted line in FIG. 2, which has the serious disadvantage of causing a wire breakage.
The present invention provides a semiconductor device manufacturing method 35 for improving the drawbacks of the above-mentioned conventional semiconductor device manufacturing methods.

The method for manufacturing a semiconductor device according to the present invention involves processing the surface layer of the aluminum layer of the wiring layer to change it into a 2O3/NLL20 layer, and using this layer as an insulating coating in the device, so that it has good adhesion with the wiring layer. The aluminum layer is characterized in that it can be obtained very well and exhibits strong electrical insulation, and that the aluminum layer can be etched using this layer as a mask.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings regarding one embodiment of a method for manufacturing a semiconductor device.

Figures 3a to 3j show some MOSFs of an example MOSIC.
The manufacturing process of ET is shown. 1 in Figure a is an N-type silicon substrate, and a SiO2 film 2 is formed on its 1 main surface (Figure a).
Next, the SiO2 film 2 is etched to form openings 2a and 2i (FIG. b). A P-type impurity such as boron is diffused and introduced through the opening to form source and drain P-type regions 3, 3/3.
(Figure c). Then, a SiO2 film is formed (Figure c)
After that, the SiO2 film is removed to form a gate portion (Fig. d). A gate oxide film 4 of SiO2 is mainly formed in the portion where the SiO2 film has been removed (FIG. e). Next, an opening 3a for exposing a part of the source and drain regions 3, 3',
31 (Figure f), then an aluminum layer 15 as a wiring metal layer is deposited (Figure g). Next, in boiling water for about 1
By performing the treatment for 0 to 20 minutes, an M2O3.NH2O layer 16 is formed on the exposed surface layer of the aluminum layer 15, and a photoresist layer 17 is further deposited and formed by etching into a predetermined pattern shape. (Figure h). The above 03・NH2O is treated at a treatment temperature of 80℃, A2O3・3H20 (Bayermite), 100℃
At A! 203.1H20 (boehmite). Note that it can be formed in the same way even if it is heated in pressurized steam.
Next, using the photoresist layer 17 as a mask, the M2
The O3/NH2O layer 16 is etched away (FIG. 1). For the above etching, ammonium fluoride (NH4F), acetic acid (CH3
A mixture of COOH) is preferably used. Next, using the remaining He2O3/NH2O layers 16' and 16Z161 as a mask, the aluminum layer 15 is treated with an example of phosphoric acid (H3PO).
4) The circuit pattern electrodes 15', 15〃, and 15I' are formed by etching and dissolving using an etching solution consisting of a mixture of nitric acid (03), acetic acid (CH3COOH), and water (Fig. J). . The wiring aluminum layer in the MOSIC of the present invention formed as described above has Al2O3 formed on its surface layer.
・Equipped with an NH2O layer, which has better adhesion with the aluminum layer than with the photoresist layer, and which has an Al2
Since the adhesion between the O3/NH2O layer and the photoresist layer is also good, there is no narrow part in the aluminum layer disposed across the stepped part, which was seen in the past, and the MO
There is a distinct advantage that SlC can be obtained.

Further, the present invention is easy to implement, and the semiconductor element can be heated at a low temperature, so that the shape of the diffusion region is less likely to be deformed. In addition, FIG. 4a is a cross-sectional view based on a partial cross-sectional photograph (magnification: 5000 times) of an aluminum layer and an Al2O3/NH2O layer according to the method of the present invention,
Figure b shows the aluminum layer and SiO2 layer in the conventional method.
A cross-sectional view based on a cross-sectional photograph of a part of the layer and a cross-sectional view based on a cross-sectional photograph, and a remarkable difference in adhesion between the two layers can be seen.

That is, while in Figure b, the undesired etching of the aluminum layer due to the inflow of the etching liquid between the two layers is noticeable, this is not observed at all in the present invention shown in Figure A.

[Brief explanation of drawings]

1A to 1J are cross-sectional views showing a conventional semiconductor device manufacturing method in the order of steps, FIG. 2 is a perspective view showing a part of a conventional semiconductor device, and FIGS. 3A to 3J are semiconductors of the present invention 4 is a cross-sectional view based on a cross-sectional photograph for explaining the present invention, and FIG. . 15... Aluminum layer (wiring layer), 16...
...Al2O3/NH2O layer.

Claims (1)

[Claims] 1. A step of forming an aluminum wiring layer on the surface of a semiconductor element, a step of heating the element in water or steam to form an Al_2O_3/nH_2O layer on the surface layer, and etching the Al_2O_3/nH_2O layer. A method for manufacturing a semiconductor device, comprising the steps of forming a predetermined pattern, and etching an aluminum wiring layer using the predetermined pattern of the Al_2O_3·nH_2O layer as a mask.