JPS6149439A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To obtain wirings having the high degree of integration by a method wherein an inter-layer insulating film is formed onto a lower layer wiring in a semiconductor substrate, a poly Si conductive film or insulating film and an Si glass film are superposed, an eave-shaped opening section is shaped and a metallic film is evaporated. CONSTITUTION:SiO2 2, poly Si 5 and SiO2 6 are superposed onto an Si substrate 1, to which an element is shaped previously, through a CVD method, and a photo-resist 4 is applied. The film 6 is etched in an anisotropic manner through RIE while using the resist 4 as a mask, the mask 4 is removed, and the film 5 is etched in an isotropic manner through dry type etching to form eaves consisting of the films 6 on the film 5. When Al 3 is sputtered and evaporated, Al is automatically separated vertically by the eaves, and Al wirings are formed. According to the constitution, the wirings having the high degree of integration can be shaped, and the method is effective for improving the degree of integration of a device.

Description

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

Conventional Structure and Problems Conventionally, when metal wiring is formed in a semiconductor device, a metal film is formed over the entire surface and then etched using a photoresist mask to form a metal wiring pattern.

FIG. 1 is a step-by-step cross-sectional view showing a conventional method for forming metal wiring in a semiconductor device. As shown in FIG. A film 3 is formed and a photoresist 4 is applied. After forming a wiring pattern with photoresist 4 as shown in FIG. 1(b), the underlying metal film is etched using photoresist 4 as a mask.
A wiring pattern of the metal film 3 is formed like cl.

However, with this method, a certain amount of space must be provided between the metal lines due to the etching of the metal lines, and if the space between the metal lines is shortened to achieve higher integration, noise problems will occur due to capacitive coupling between the metal lines. This is a major obstacle to increasing the degree of integration of semiconductor devices.

OBJECTS OF THE INVENTION The present invention provides a method for manufacturing a semiconductor device that eliminates the above-mentioned disadvantages.

Structure of the Invention The present invention provides that after forming an interlayer insulating film on a lower layer such as a diffusion layer or a polysilicon wiring, a second insulating film or conductive film different from the interlayer insulating film and the second insulating film or conductive film are formed. After forming a different third insulating film and selectively opening holes in the third insulating film, isotropically forming the second insulating film or the conductive film using the third insulating film as a mask. A method for manufacturing a semiconductor device that includes a step of etching the metal wires and a step of forming a metal film for wiring, which eliminates the need to provide a certain space between metal wires and allows the same design to be achieved in highly integrated semiconductor devices. The rules allow metal wiring density to be increased by up to twice as much. In addition, if every other metal wire formed by this method is used as a signal wire and the wire between the signal wires is used as an electrical shield, it will greatly contribute to countermeasures against noise between the signal wires and ensure highly reliable operation. It becomes possible.

DESCRIPTION OF EMBODIMENTS FIGS. 2(a) to dl are cross-sectional views showing an embodiment of the present invention in the order of steps. As shown in FIG. 2(a), a silicon substrate or a semiconductor in the same substrate is After forming the lower layer part (hereinafter simply referred to as the substrate) 1 with the wiring of the device, the CV
A silicon oxide film 2 having a thickness of 8,000 wafers is formed using the D method at a growth temperature of 430°C. Furthermore, a polysilicon layer 6 with a thickness of 5,000 layers is formed using the CVD method at a growth temperature of 61.0°C.
Similarly, a silicon oxide film 6 is formed to a thickness of 3000° C. by the CVD method at a growth temperature of 43° C., and then a photoresist 4 is applied. Next, as shown in FIG. 2), after forming a wiring pattern with photoresist 4, silicon oxide film 6 is anisotropically etched using reactive ion etching using photoresist 4 as a mask. After removing the photoresist 4, as shown in FIG. 2(0), the polysilicon film 5 is
Using the silicon oxide film 6 as a mask, isotropic etching is performed using a dry etching method so that a stretch of the silicon oxide film 6 is formed on the polysilicon film 6. When the aluminum film 3 is sputter-deposited to a thickness of 8000 mm as shown in FIG. Thereafter, it is necessary to wet-oxidize the etched side surface of the polysilicon film 5 to form an oxide film to insulate the signal lines.

In this example, as materials for the eaves, a silicon oxide film was used as the upper insulating film, and a polysilicon film was used as the lower layer. Any type of film may be used.

Furthermore, although an aluminum film is used as the metal wiring material, other wiring materials such as high melting point metals may be used.

Effects of the Invention As is clear from the above explanation, if the present invention is used, the degree of integration of metal wiring will be greatly improved, and it will have great industrial value for increasing the integration of semiconductor devices.

[Brief explanation of the drawing]

FIGS. 1A to 1C are process cross-sectional views of the conventional metal wiring method for semiconductor devices, and FIGS. 2A to 2D are process cross-sections of an embodiment of the metal wiring method for semiconductor devices according to the present invention. 0 1... Semiconductor substrate on which predetermined circuit elements are formed, 2... Interlayer insulating film, 3... Metal wiring film, 4... Photo Resist, 5... Insulating film or conductive film, 6... Insulating film.

Claims (2)

[Claims] (1) After forming an interlayer insulating film between an electrode portion or a lower wiring of a semiconductor device, forming a second insulating film or a conductive film different from the interlayer insulating film and a third insulating film different therefrom; , after selectively opening holes in the third insulating film, isotropically etching the second insulating film or the conductive film using the third insulating film as a mask; and a metal film for wiring. A method of manufacturing a semiconductor device, the method comprising: forming a semiconductor device. (2) The method for manufacturing a semiconductor device according to claim 1, wherein the third insulating film is silicon glass, and the second insulating film or conductive film is polysilicon.