JPH02229432A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent a second wiring layer from being disconnected by a method wherein an insulating film is applied to a metal thin film used as a first wiring layer applied to a semiconductor substrate, a resist is then patterned, the insulating film is etched isotropically by using the resist as a mask and the metal thin film is etched anisotropically by using the resist as the mask. CONSTITUTION:An Al-Si film 3 is vapor-deposited on the surface of a semiconductor substrate 1 to which a thermal oxide film 2 has been applied. Then, an NSG film 4 is deposited. Then, a patterned resist 5 is formed. Then, the NSG film 4 is etched isotropically by using a buffer solution of hydrofluoric acid and ammonium fluoride by making use of the resist 5 as a mask. Then, the Al-Si film 3 is etched anisotropically by making use of the resist 5 as the mask. Then, when the resist 5 is removed, angles alpha as cross-sectional parts constituted of the Al-Si film 3 and the NSG film 4 become obtuse angles; when a P-SiN film 6 is deposited as an interlayer insulating film, coating shapes of the interlayer film at parts of the angles alpha do not become eaves-shaped and the parts are covered gently. Even when an Al-Si film 7 is vapor-deposited as a second wiring layer in 1.5 to 2.0mum, no disconnection is caused.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method of manufacturing a semiconductor device having highly reliable multilayer wiring.

Conventional technology In recent years, the density of semiconductor devices has increased. With higher integration and faster speeds, interconnect dimensions are becoming smaller and interconnects are becoming more multi-layered.

A two-layer wiring formed by a conventional method will be described below. FIG. 3 is a cross-sectional view of a two-layer wiring formed by a conventional method, in which 1 is a semiconductor substrate, 2 is a thermal oxide film, 3 is a first wiring layer, 6 is an insulating film between the eyebrows, and 7 is a second wiring layer. It is.

As wiring becomes finer, the first wiring layer is often patterned mainly by anisotropic etching, and its cross-sectional shape is almost vertical and the angle is right angle.

Problems to be Solved by the Invention However, when an interlayer insulating film is deposited on the anisotropically etched first wiring layer, at the location where the first wiring layer surface and the etched surface intersect, as indicated by β in FIG. , the interlayer insulating film is excessively deposited, and when viewed in cross section, it has an eave-like shape. When the second wiring layer is deposited on the glabella insulating film, there is a problem in that the second wiring layer is likely to be disconnected at the eaves-shaped portion.

The present invention solves the above-mentioned conventional problems, and provides a method for manufacturing a semiconductor device that improves the adhesion shape of an interlayer insulating film and prevents disconnection of the second wiring layer.

Means for Solving the Problems In order to achieve this object, the present invention further deposits an insulating film on a metal thin film that is the first wiring layer that is deposited on the entire surface of a semiconductor substrate, and then patterns a resist. After ning,
This method of manufacturing a semiconductor device includes the steps of isotropically etching an insulating film on the resist mask, and then anisotropically etching a metal thin film on the resist TF mask.

According to the configuration of the present invention, the angle of the cross section formed by the first layer wiring and the insulating film is not a right angle but an obtuse angle, and the covering properties of the interlayer insulating film deposited thereon are also improved, resulting in a canopy shape. Therefore, disconnection of the second layer wiring can be prevented, and a highly reliable multilayer wiring can be formed.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a semiconductor device obtained by the present invention, and FIGS. 2 a-f are cross-sectional views in the order of steps of an embodiment of the present invention. Firstly, as shown in FIG. S~1.
Deposit 2 μm.

Next, as shown in Figure 2b, C V D (Chemi
NSG (Man-doped Silicate)
Glass) film 4 is deposited to a thickness of 200 to 600 times. Next, as shown in FIG. 2C, a patterned resist 6 is formed by a normal photolithography technique. Next, as shown in FIG. 2d, this resist 6'l
NS with a buffer solution of hydrofluoric acid and ammonium fluoride on the T-mask.
The G film 4 is isotropically etched. Next, as shown in FIG.
Perform anisotropic etching using ng expansion. Next, when the resist 6 is removed, a structure as shown in FIG. 3f is obtained, and the angle α in FIG. Then, when a 1 μm thick P-SiN film 6 was deposited as an interlayer insulating film, the covering shape of the glabellar film at the point α in FIG. Then, as a second wiring layer, a ▲l-Si film 7 with a thickness of 1.6 to 2.0
Even with μm deposition, no disconnection occurs.

Effects of the Invention As explained above, according to the method for manufacturing a semiconductor device of the present invention, the covering shape of the interlayer insulating film in the multilayer wiring process can be improved, the disconnection of the wiring in the second and subsequent layers can be prevented, and high reliability can be achieved. Multilayer wiring can be easily formed.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a semiconductor device obtained by the method of the present invention;
Figures 2-8-g are process cross-sectional views of an embodiment of the present invention;
The figure is a cross-sectional view of a conventional semiconductor device. 1... Semiconductor substrate, 2... Thermal oxide film,
3...First wiring layer, 4...Insulating film, 5
...Resist, 6...Interlayer insulating film, 7
...Second wiring layer, 8...Protective film. Name of agent: Patent attorney Shigetaka Awano and 1 other person/・
1st half body board 2 11th film 3 - 11th layer 3

Claims (1)

[Claims] A process of depositing a metal thin film for wiring on the entire surface of the semiconductor substrate,
a step of depositing an insulating film on the entire surface of the semiconductor substrate; a step of patterning a resist on the semiconductor substrate;
A method for manufacturing a semiconductor device, comprising the steps of isotropically etching an insulating film using the resist as a mask, and anisotropically etching a metal thin film using the resist as a mask.