JPH03184344A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain a semiconductor device having a metal interconnection structure of multilayers and no reductions in yield and reliability by providing a polysilicon protective film formed on a wiring necessary conductive film. CONSTITUTION:In a semiconductor device having two or more multilayer interconnection structure and polysilicon protective films 14, 15, 18, 19 formed on wiring conductive films 13, 17 is provided. For example, an insulating film 12 in which a diffused layer electrode output port is opened is formed on a semiconductor substrate 11, and a first Al film 13 is deposited. Then, the film 14 is deposited thereon, and the films 14, 13 are patterned. Thereafter, the film 15 is deposited, the film 15 remains on the sidewall of the film 13 by RIE, and boron is ion implanted to the films 14, 15. Then, an interlayer insulating film 16 is deposited, an interwiring electrode output port is opened, wiring layers 17-19 are similarly formed, and an insulating film 20 is eventually deposited.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a semiconductor device and a method for manufacturing the same.

(Prior Art) Conventionally, in a semiconductor device having a multilayer metal wiring structure and a method for manufacturing the same, a technique as described below with reference to FIGS. 2(a) to (f) has been used. Ta.

First, as shown in FIG. 4A, an insulating layer 112 having a diffusion layer electrode outlet is formed on a semiconductor substrate 1 on which an element region is formed. Next, as shown in FIG. 3B, a first Ag film 3 is deposited on the semiconductor substrate. Thereafter, a photoresist is applied, the first Al film 3 is patterned by a normal photolithography process, and the photoresist is peeled off. Next, as shown in the same figure (C),
Braz v CV D (Chemical Vapor
The first Ail film 3 is
An interlayer insulating film 4 is formed thereon.

Next, as shown in FIG. 4(d), a photoresist is applied, and then the interlayer insulation H4 is opened by a normal photolithography process, and the photoresist is peeled off. Next, as shown in FIG. 5(e), a second AfI film 5 is deposited, and then a photoresist is applied, and the second AD film 5 is patterned using a normal photolithography process. Exfoliate the cyst. Finally, as shown in FIG. 6(f), an insulating film 6 is formed on the second film 5 by atmospheric pressure CVD. However, this manufacturing method and the semiconductor device manufactured by this manufacturing method have the following drawbacks.

First, when opening the inter-wiring electrode outlet in the insulating film formed on the first AN interconnect, the surface of the first l) interconnect is also etched, so the inner wall of the inter-wiring electrode outlet is etched. A product is formed, resulting in poor coverage of the second wiring AN film.

Second, when an AN film for wiring is subjected to reactive ion etching using a chlorine-based gas, the residual gas causes an
Wiring is prone to corrosion. Alternatively, the Ag wiring is likely to corrode due to the water washing treatment after etching. Further, a technique of forming a metal film of chromium, molybdenum, titanium, or the like on the first Al film may be used, but the metal film tends to cause corrosion of the A and Q wirings and is difficult to pattern.

Due to the above-mentioned causes, disconnection of metal wiring or poor contact between metal wirings occurs, resulting in a decrease in yield and reliability of semiconductor devices.

(Problems to be Solved by the Invention) As described above, conventional semiconductor devices having a multilayer metal wiring structure have had the disadvantage of causing a reduction in yield and reliability.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an excellent semiconductor device having a multilayer metal wiring structure that does not cause a decrease in yield or reliability, and a method for manufacturing the same.

[Structure of the Invention] (Means for JW-Determining the Problems) In order to achieve the above object, a semiconductor device according to the present invention has a multilayer wiring structure of two or more layers, and has a multilayer wiring structure formed on the surface of a conductive film for wiring. It is characterized by having a polysilicon protective film.

Further, in manufacturing a semiconductor device having a multilayer wiring structure of two or more layers, the method for manufacturing a semiconductor device according to the present invention includes a step of forming a conductive film for wiring, and a polysilicon protective film on the conductive film for wiring. The method is characterized by comprising a step of forming a conductive film for wiring, a step of patterning the conductive film for wiring and the polysilicon protective film, and a step of implanting an impurity into the polysilicon protective film. Due to this,
In a semiconductor device having a multilayer metal interconnection structure, it is possible to provide an excellent semiconductor device and a method for manufacturing the same without a decrease in yield or reliability.

(Function) In the above semiconductor device and its manufacturing method, since a polysilicon protective film is formed on the surfaces of the A and Q wirings, the first
A, when the insulating film formed on the lit wiring is opened, no product is formed on the inner wall of the inter-wiring electrode extraction opening, and the second wiring 1
Membrane coverage has been updated.

In addition, because the AN wiring is not exposed during the AJ wiring patterning process or the subsequent water washing process, 1
Corrosion of one wiring can be suppressed.

As a result of the above, disconnection of metal wiring or poor contact between metal wiring can be prevented.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to FIGS. 1(a) to (i).

First, as shown in FIG. 4A, an insulating film 12 having an opening for taking out a diffusion layer electrode is formed by CVD on a semiconductor substrate 11 on which an element region is formed. Next, the same figure (b
), a first Al film 13 is deposited on the semiconductor substrate 11 and the insulating film 12 using a sputtering method. Next, as shown in FIG. 2C, a first polysilicon protective film 14 is deposited on the first A heavy film 13 by low-temperature atmospheric pressure CVD. Further, a photoresist is applied, the first polysilicon protective film 14 and the first A, 17 film 13 are patterned by a normal photolithography process, and the photoresist is peeled off. Furthermore, heat treatment is performed in a vacuum to remove attached impurities. Next, as shown in FIG. 2D, the semiconductor substrate 11 and the first polysilicon protective film 1 are
A second polysilicon protective film 15 is deposited on the second polysilicon protective film 15 by a low temperature atmospheric pressure CVD method.

Next, as shown in FIG. 3(e), by reactive ion etching the entire surface of the second polysilicon protective film 15, the second polysilicon protective film 15 is etched with the first Ag.
It remains on the side wall of the membrane 13. This is to protect the side surfaces of the patterned Ag wiring. Next, a resist is applied to the entire surface, and a resist film is formed only on the insulating film 12 by a normal photolithography process. Further, using this resist film, boron ions are implanted into the first polysilicon protective film 14 and the second polysilicon protective film 15 in order to conduct the electrodes between the wirings. Next, as shown in FIG. 3(f), an interlayer insulating film 1B is deposited on the first polysilicon protective film 14 and the second polysilicon protective film 15 by plasma CVD, and a photolithography process is further performed. Use this to open a hole for taking out the electrode between the wires. Next, the same figure (g
), the second AI is applied to the entire surface using a sputtering method.
After depositing film 17 and further depositing third polysilicon protective film 18 thereon, these are patterned using a photolithography process. Next, as shown in the same figure (h), after performing heat treatment to remove impurities, the third
A fourth layer is formed on the polysilicon protective film 18 and the interlayer insulating film te.
A fourth polysilicon protective film 19 is deposited, and etched and patterned so that this fourth polysilicon protective film 19 remains on the side walls of the first Al film wiring 17. Finally, as shown in FIG. 3(i), an insulating film 20 is deposited over the entire surface by atmospheric pressure CVD.

[Effects of the Invention] As described above, according to the semiconductor device and the manufacturing method thereof of the present invention, the following effects are achieved.

Since a polysilicon protective film is formed on the surface of the AM wiring, when opening a hole for taking out an electrode between lines in the insulating film formed on the first All wiring, the inner wall of the hole for taking out an electrode between lines is formed in this hole. Since no products are formed, the coverage of the second wiring Ag film is improved. In addition, in Afi wiring patterning or the subsequent water washing process,
Since the j7 wiring is not exposed, corrosion of the Al wiring can be prevented. As a result, in a semiconductor device with a multilayer metal wiring structure and its manufacturing method, it is possible to prevent disconnection of metal wiring or poor contact between metal wiring, resulting in an excellent semiconductor device without a decrease in yield or reliability. and a manufacturing method thereof can be provided.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view for explaining a semiconductor device and its manufacturing method according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view for explaining a conventional semiconductor device and its manufacturing method. be. 11... Semiconductor substrate, 12... Insulating film, 13...
first Ag film, 14... first polysilicon protective film,
15... Second polysilicon protective film, 1B... Interlayer insulating film, 17... Second A, 9 film, 18... Third
polysilicon protective film, 19... fourth polysilicon protective film, 20... insulating film.

Claims (2)

[Claims] (1) A semiconductor device having a multilayer wiring structure of two or more layers, and comprising a polysilicon protective film formed on the surface of a conductive film for wiring. (2) A method for manufacturing a semiconductor device having a multilayer wiring structure of two or more layers, which includes the steps of forming a conductive film for wiring, forming a polysilicon protective film on the conductive film for wiring, and A method for manufacturing a semiconductor device, comprising the steps of patterning a conductive film for wiring and the polysilicon protective film, and implanting impurities into the polysilicon protective film.