JPH01251641A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To flatten an interlayer insulating film without etching treatment, and manufacture a semiconductor device having an interlayer insulating film excellent in insulating property, by forming a lower wiring so as to be buried in a wiring trench formed on a flat insulating film, and forming, thereon, a second insulating film. CONSTITUTION:A photo resist film 4 is spread and formed, and a wiring trench 6 is formed by etching an aluminum film 3 and an insulating film 2 in the part where a lower wiring is formed. By sputtering titanium, platinum, etc., on the whole surface, a titanium platinum film 6 is formed. After that, the titanium platinum film 6 except the trench 5 is eliminated by lift-off method; a photo resist film 7 is spread; the part of the wiring trench 5 is opened; a gold-plated layer is formed in the wiring trench 5 in a buried state by gold-plating treatment; a lower wiring layer 8 is formed thereby; the photo resist film 7 is eliminated; the aluminum film 3 is eliminated by wet etching; and a second insulating film 9 is grown. Thus an interlayer insulating film having a flat upper surface is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for manufacturing a semiconductor device that achieves planarization between wiring layers in a multilayer wiring structure.

[Conventional technology]

Conventionally, in semiconductor devices having a multilayer wiring structure, the glabella insulating film formed on the lower wiring has been flattened for the purpose of improving processing accuracy of the upper wiring, improving migration resistance, and preventing disconnection. ing.

In this case, the general method is to apply an insulating film on the uneven surface of the glabellar insulating film formed on the lower wiring, and to etch back this insulating film and the glabellar insulating film. A method of flattening the top surface is used.

[Problem to be solved by the invention]

In the conventional method described above, if the upper surface of the insulating film coated on the glabellar insulating film is not flat, it is difficult to flatten the upper surface of the glabellar insulating film even if etching back is performed. In addition, when the wiring spacing becomes narrower and the uneven surface that occurs in the glabellar insulating film becomes minute, it becomes difficult to apply the insulating film without creating cavities within these minute recesses, forming a highly insulating glabellar insulating film. The problem is that it cannot be done.

An object of the present invention is to solve the above-mentioned problems and provide a method for manufacturing a semiconductor device having a glabellar insulating film with excellent flatness and insulation properties.

[Means to solve the problem]

The method for manufacturing a semiconductor device of the present invention includes a step of forming an insulating film on a semiconductor substrate, and a step of selectively etching the insulating film using a photoresist film to form a wiring groove at a lower wiring formation location. , a step of forming a conductive film on the entire surface including the wiring groove and embedding the conductive film in the wiring groove; a step of peeling off the photoresist film to remove the conductive film other than the wiring groove; and a step of growing a second insulating film.

[Effect]

In the method described above, the lower wiring is buried in a wiring groove formed in a flat insulating film, and the second insulating film is formed on top of the lower wiring, thereby flattening the glabella insulating film without etching. achieve the goal of

〔Example〕

Next, the present invention will be explained with reference to the drawings.

1 to 6 are cross-sectional views showing an embodiment of the present invention in the order of manufacturing steps.

First, as shown in FIG. 1, an insulating film 2 made of silicon nitride (S iz N4 ), silicon oxide (SiOz), or the like is grown on a semiconductor substrate 1 by vapor phase growth. Furthermore, an aluminum film 3 is formed thereon by sputtering.

Next, as shown in FIG. 2, a photoresist film 4 is applied and formed, and the aluminum film 3 and insulating film 2 at the locations where the lower wiring is to be formed are etched using the photoresist film 4 as a mask or by lithography to form the wiring. A groove 5 is formed.

Subsequently, as shown in FIG. 3, titanium, platinum, or the like is sputtered over the entire surface to form a titanium/platinum film 6 at least on the bottom and side surfaces of the wiring trench 5. Thereafter, by peeling off the photoresist film 4, the titanium/platinum film 6 other than the wiring groove 5 is removed by a so-called lift-off method, as shown in FIG.

Next, as shown in FIG. 5, a photoresist film 7 is applied again, and the previously used photomask is again used to form a pattern to open the wiring groove 5. Then, by performing a gold plating process, a gold plating layer is buried in the wiring groove 5 to form a lower wiring layer 8.

In this case, it is important to manage the plating process so that the gold plating layer has the same thickness as the insulating film 2.

Then, as shown in FIG. 6, the photoresist film 7 is removed, the aluminum film 3 is removed by wet etching, and a second insulating film 9 that is the same as or different from the insulating film 2 is grown thereon. , it is possible to form a glabella insulating film with a flat upper surface.

Note that it goes without saying that the upper wiring is formed on this glabellar insulating film.

Therefore, this manufacturing method eliminates the need for the step of applying an insulating film on the upper surface of the glabellar insulating film and the step of etching back these insulating films and the glabellar insulating film, and eliminates the above-mentioned problems in these steps. do not have. As a result, it is possible to obtain a glabellar insulating film with excellent flatness and insulation, improve the processing accuracy of the upper wiring, improve migration resistance, and prevent disconnection.

It goes without saying that the aluminum film, titanium/platinum film, etc. can be made of other materials.

〔Effect of the invention〕

As explained above, the present invention embeds the lower wiring in a wiring trench formed in a flat insulating film, and forms a second insulating film on top of the lower wiring, thereby forming a layer on the glabella insulating film. While eliminating the need for the process of applying an insulating film and the process of etching the glabellar insulating film, the glabellar insulating film can be made flat, improving the processing accuracy of the upper wiring, improving migration resistance, and preventing disconnection. .

[Brief explanation of the drawing]

1 to 6 are cross-sectional views showing the present invention in the order of manufacturing steps. DESCRIPTION OF SYMBOLS 1... Semiconductor substrate, 2... Insulating film, 3... Aluminum film, 4... Photoresist film, 5... Wiring groove, 6... Aluminum film, 7... Photoresist Film, 8... Lower wiring (gold plating layer), 9... Second insulating film. Figure 1 Color (1 Figure 4 Figure 5

Claims (1)

[Claims] 1. A process of forming an insulating film on a semiconductor substrate, a process of selectively etching this insulating film using a photoresist film, and forming a wiring groove at a lower wiring formation location, and a process of forming an entire surface including this wiring groove. a step of forming a conductive film on the substrate and embedding the conductive film in the wiring trench; a step of peeling off the photoresist film to remove the conductive film other than the wiring trench; and growing a second insulating film over the entire surface. A method for manufacturing a semiconductor device, comprising the steps of: