JPS6035825B2 - Manufacturing method of semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for forming a buried wiring layer having a flat surface.

To form multilayer wiring, which is often used in integrated circuit devices (IC) and large-scale integrated circuit devices (BI), the surface of a first wiring body formed according to a predetermined pattern is covered with an insulating film, and this A method is used in which a closure is provided in an insulating film according to a predetermined pattern, and then a second wiring body is covered.

However, with this method, as the process progresses, the unevenness of the surface of the semiconductor substrate becomes larger, making patterning difficult, and there are also problems such as film breakage of the second wiring body at the shoulder of the closing part of the insulating film. be.

Therefore, in order to improve this, an insulating film 3 made of, for example, phosphorous silicate glass (PSG) is coated on the silicon dioxide film 2 covering the surface of the silicon substrate 1, as shown in FIG. 1a.
A photoresist film 5 with the electrode wiring pattern to be formed as a closed part 4 is selectively removed using a mask to provide a closed part 6 in the insulating film 3.

Next, as shown in Figure b, a conductive material for electrode wiring, such as aluminum (mountain), is deposited on the surface of the silicon substrate by vapor deposition or sputtering, and a conductive material film 7 and 7' is formed. Next, the photoresist film 5 is removed by a plasma attachment method or the like, and the conductive material film 7' deposited on the photoresist film 5 is lifted off and removed at the same time, and the conductive material is applied to the insulating film 3 as shown in FIG. A method has been proposed for forming an electrode wiring layer in which the layer 7, that is, the wiring body 7 is embedded and has a flat surface.

However, as shown in FIG. 2A, in this method, side etching is unavoidable when the insulating pus 3 is etched using the photoresist film 5 as a mask, and lateral etching also progresses below the photoresist film 5.

Therefore, when the openings 6 and 6' of a fine pattern are arranged at minute intervals, the inside of the top of the insulating film 3' between the closed openings 6 and 6' becomes very narrow, as shown in Figure b. The photoresist film peels off.

After that, as described above, even if a conductive material such as aluminum (AI) is deposited and an unnecessary portion of the conductive material film is removed by the lift-off method, the closed holes 6, 6 as shown in FIG.
It is not possible to separate the conductive material films 7 and 7' formed on the conductive material films 7 and 7'.

Since this method has such drawbacks, it is difficult to form electrode wiring with a fine pattern.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for forming a buried electrode wiring layer that solves the above-mentioned problems and enables the formation of electrode wiring with fine patterns and minute intervals. The method for manufacturing a semiconductor device of the present invention is characterized by a step of forming a photoresist film on the surface of the semiconductor substrate in accordance with an electrode wiring pattern to be formed when forming electrode wiring on the surface of the semiconductor substrate, and a step of forming an insulating film on the surface of the semiconductor substrate. A step of laminating and depositing a thin film made of a material having etching selectivity between the film and the insulating film, and removing the photoresist film to make the insulating film and the thin film scarlet on the photoresist film. a step of simultaneously removing a conductive material film for electrode wiring on the surface of the semiconductor substrate; and a step of simultaneously removing a conductive material film for electrode wiring to be deposited on the thin film by removing the thin film. It is to include.

Embodiments of the method for manufacturing a semiconductor device of the present invention will be described below with reference to the drawings.

FIG. 3 is a sectional view of a main part showing the above embodiment in the order of steps.

As shown in FIG. 1A, the photoresist film 5 is coated approximately 1.5 [m] in accordance with the electrode wiring pattern to be formed on the silicon dioxide (Si02) film 2 covering the surface of the silicon substrate 1.
Form to a thickness of .

Next, as shown in Figure b, for example, silicon monoxide (Si
A thin film 8 made of polycrystalline silicon is deposited to a thickness of about 1 mm using circular evaporation or sputtering to a thickness of about 1000 A.

At this time, the thickness of the photoresist film 5 is thicker than the sum of the thicknesses of the Si○ film 3 and the thin film 8 made of polycrystalline silicon. The membrane 3 and the thin membrane 8 are connected and not connected.

Next, the photoresist film 5 is removed using an atssia method or the like to remove the Si deposited on the photoresist film 5.
○A gate 6 is formed in the insulating film 3 made of Si0 as shown in FIG.

Since no etching method is used to form the opening 6, side etching as described above does not occur.

Therefore, it is possible to accurately form fine-sized sekiguchi at fine intervals. Next, as shown in Figure d, a conductive material for electrode wiring such as aluminum (N) is deposited to a thickness of about 1 m by vapor deposition or sputtering.

At this time as well, the conductive material layer 7 and the thin film 8 to be deposited inside the Sekiguchi 6
The conductive material film 7' deposited thereon is not connected.

Next, as shown in FIG. At the same time, the conductive material film 7' is removed.

Through the above steps, a buried wiring layer 9 having the conductive material film 7 buried in the insulating film 3 as an electrode wiring body was formed.

Since the surfaces of the insulating film 3 and the electrode wiring body 7 of the plummeted wiring layer 9 form a substantially flat surface, there will be no disconnection even if multilayer wiring is formed using this layer, and there is no side etching. Fine pattern wiring can be formed with high precision. What is important in the above steps is to use a combination of materials for the thin film 8 and the insulating film 3 that allows only the thin film 8 to be selectively etched in order to enable the conductive material film '7' on the thin film 8 to be lifted off.

Table 1 shows some examples of material combinations that can be selectively etched.

Although the above embodiments have been described with reference to the case where the conductive material constituting the electrode wiring body is aluminum (AI), the conductive material does not need to be limited to aluminum.

For example, when using the present invention to form a polycrystalline silicon wiring body often used in MOSICs, etc., the combination of insulating film and thin film materials should be selected as shown in Table 1. 2, No. 4 or No. This can be implemented by setting 5.

As described above, the present invention can be implemented by selecting a combination of materials for the insulating film and thin film that can be selectively etched depending on the conductive material used. Further, in the above embodiments, the case where only one buried wiring layer is formed has been described, but by repeating the above embodiments, etc., it is possible to easily form multilayer wiring with fine patterns with high precision.

As described above, according to the present invention, a buried wiring layer having a fine, high-density, and flat surface can be easily formed with high precision.

Therefore, multi-layering can be easily achieved without causing disconnections or short circuits.

[Brief explanation of drawings]

FIGS. 1 and 2 are sectional views of essential parts for explaining a conventional buried wiring forming method, and FIG. 3 is a sectional view of essential parts showing an embodiment of the present invention. 1... Semiconductor substrate, 3, 3'... Insulating film, 5... Photoresist film, 6... Sekiguchi, 7, 7'
... Conductive material film, 8... Thin film, 9...
Embedded wiring layer. Tsutomu hair 2 illustration younger brother 3 illustration

Claims (1)

[Claims] 1. When forming electrode wiring on the surface of a semiconductor substrate, a step of forming a photoresist film on the surface of the semiconductor substrate according to the electrode wiring pattern to be formed, and etching selectivity between the insulating film and the insulating film. a step of laminating and depositing a thin film made of a material on the semiconductor substrate surface; a step of simultaneously removing the insulating film and the thin film deposited on the photoresist film by removing the photoresist film; A method for manufacturing a semiconductor device, comprising the steps of: depositing a conductive material film for electrode wiring on the substrate; and removing the thin film and simultaneously removing the conductive material film deposited on the thin film.