JPH02272736A - Manufacturing method of semiconductor device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a method of manufacturing wiring for a semiconductor device [Prior Art] The wiring for a conventional semiconductor device is generally as shown in FIG. Made of aluminum-silicon alloy. At this time, the aluminum-silicon alloy had good workability, and it was possible to form wiring with relatively high dimensional accuracy using common dry etching techniques.

However, as semiconductor integrated circuits have become more highly integrated in recent years, there has been a demand for wiring materials that have lower resistance than aluminum-silicon alloys and are more resistant to migration.

[Problem to be solved by the invention] Steel is an example of a wiring material that has lower resistance than aluminum alloy and is more resistant to migration, but these metals have poor processability and cannot be easily processed using existing dry etching techniques. It could not be etched and it was extremely difficult to make wiring.

Therefore, the present invention aims to solve such problems, and provides a method for manufacturing a semiconductor device that allows easy wiring of steel, which is a wiring material that has lower resistance than aluminum alloy and is highly resistant to migration. It provides:

[Means for Solving the Problems] The semiconductor manufacturing apparatus of the present invention includes a step of forming a first conductive film on the entire surface of a first insulating film formed above a semiconductor substrate, and a step of forming a first conductive film on the entire surface of a first insulating film formed above a semiconductor substrate. a step of forming a second insulating film in a pre-designed region of the first conductive film; a step of selectively forming a second conductive film in a region not covered with the second insulating film on the first conductive film; The method is characterized by comprising a step of removing the second insulating film, and a step of selectively removing the first conductive film using the second conductive film as a mask.

[Example] FIG. 1 is a cross-sectional view showing the structure of a semiconductor device manufactured by the method of manufacturing a semiconductor device of the present invention. That is,
Aluminum-silicon alloy 10 obtained by the present invention
3 shows a wiring having a two-layer structure of copper 105 and copper 105.

FIG. 2 is a process sectional view showing an embodiment of the method for manufacturing a semiconductor device of the present invention. The steps will be explained in detail below.

First, as shown in FIG. 2(a), a semiconductor substrate 101
An aluminum-silicon alloy 103 is formed as a first conductive film on the entire surface of the silicon oxide film 102 formed above by sputtering.

Next, as shown in FIG. 2(b), a photoresist resist 104 with a film thickness of 100% is applied as a second insulating film only to areas on the aluminum-silicon alloy 103 that will not become wiring.
Form 00 people. At this time, in order to form an insulating film only in areas that will not become wiring, aluminum-silicon alloy 10
It is only necessary to remove the photoresist 104 coated over the entire surface of the photoresist 104 by photolithography in only the area designed to become the wiring.

Next, as shown in FIG. 2(C), a photoresist 10
Aluminum-silicon alloy 103 in the area not covered by 4, that is, the area designed to become wiring
1i105 is selectively formed as a second conductive film only on top. At this time, copper 105 was selectively formed only on the aluminum-silicon 103 alloy by plating technology. The film thickness of the copper 105 at this time was 6000.

The specific resistance of copper is about 60% of that of aluminum, so
When trying to obtain the same current capacity with wiring of the same line width, the film thickness may be 60% of that of aluminum.

Next, as shown in FIG. 2(d), a photoresist 10
Remove 4.

Finally, as shown in FIG. 2(e), the aluminum-silicon alloy 103 is removed by dry etching using the copper 105 as a mask. Dry etching is performed using a mixed gas containing boron trichloride (BCl2) and chlorine (Cl2) as main components, and under these conditions 1jl105 is hardly etched.

Note that although an aluminum-silicon alloy is used as the first conductive film in this example, any conductive film that can be easily removed by etching may be used. For example, high-melting point metals such as tungsten, molybdenum, titanium nitride, and titanium-tungsten Alternatively, a high melting point metal compound may be used.

Further, in this embodiment, the first conductive film is a single layer, but it may be a multilayer film consisting of a combination of some of the above-mentioned conductive films.

Further, the second conductive film may be any conductive material as long as it can be selectively grown on the first conductive film, and in addition to steel, for example, gold, chromium, nickel, etc. can be considered.

Further, as the second insulating film, an inorganic material such as a silicon oxide film or a nitride film may be used instead of the photoresist.

[Effects of the Invention] As described above, according to the present invention, it is difficult to selectively etch pre-designed areas on an easily etched aluminum-silicon alloy formed entirely on a silicon oxide film. By forming a copper layer and removing the aluminum-silicon alloy by etching using the copper as a mask, it is possible to easily obtain a multilayer interconnection structure containing copper, which is difficult to remove by etching. It is possible to easily form a wiring having a lower resistance and a migration resistance of 8 ffl than that of the wiring, and has the effect that a highly reliable semiconductor device can be manufactured at a high yield.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the structure of a semiconductor device obtained by the method of manufacturing a semiconductor device of the present invention. FIGS. 2(a) to 2(e) are process cross-sectional views showing an embodiment of the method for manufacturing a semiconductor device of the present invention. FIG. 3 is a cross-sectional view showing an example of the structure of a conventional semiconductor device. 103.303 Aluminum-silicon alloy 104
Photoresist 105 Copper Windward Applicant Seiko Epson Co., Ltd. Agent Patent Attorney Kizobe Suzuki and 1 other person 101.301 Semiconductor substrate 102.302 Silicon oxide film 3 oa

Claims (1)

[Claims] a step of forming a first conductive film on the entire surface of the first insulating film formed above the semiconductor substrate; a step of forming a second insulating film in a predesigned region on the first conductive film; a step of selectively forming a second conductive film on a region not covered with the second insulating film on the first conductive film; a step of removing the second insulating film; and a step of removing the second conductive film. A method for manufacturing a semiconductor device, comprising the step of selectively removing the first conductive film using as a mask.