JPH0590426A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To dissolve a leak fault by performing etching not exceeding 2000Angstrom on the surface of an interlayer insulating film consisting of polyimide group resin followed by forming a second insulating film. CONSTITUTION:Prior method of formation is applied so far as to an upper layer aluminium wiring 7. Next, in a plasma CVD device, a substrate 1 is put in a reactor so as to reduce pressure followed by introducing oxygen gas so as to hold pressure at about 1Torr and adding 2Kw of RF power about the same with film growth for being subjected to treatment for about three minutes in order to perform etching of about 500 to 1000Angstrom on the polyimide surface. Later, once vacuum coating is performed, a raw material gas such as ammonium, silane is introduced so as to put on a silicon nitride film 8. Up to now, gas fluoride such as SF6, NF3 and hydrogen gas are introduced to a plasma CVD device for cleaning inside a reactor so that it can easily be realized also from an industrial point of view.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, and more particularly to a method of manufacturing a multi-layer wiring using a polyimide film as an interlayer insulating film.

[0002]

2. Description of the Related Art A conventional method for manufacturing a polyimide interlayer insulating film multilayer wiring will be described with reference to FIG. The lower layer aluminum wiring 2 made of an aluminum alloy is formed on the substrate 1 (a). Next, after applying a polyimide precursor solution by spin coating, the temperature is about 100 ° C.
To about 400 ° C. and the 1.0 μm layer polyimide film 3 is applied to form an interlayer insulating film (b). 2μ
A photoresist film 4 having a thickness of about m is applied and a through hole portion 5 of the photoresist is opened by photolithography (c). The photoresist film 4 and the polyimide film 3 in the through hole portion 5 were etched by the plasma etching method using oxygen gas to remove the polyimide film 3 in the through hole portion 5 and the photoresist film 4 remained about 0.5 μm. At this point, the etching is stopped (d). The photoresist is removed using a resist stripper (e). Next, an aluminum alloy film 6 having a thickness of about 1 micron is applied by the sputtering method.
The aluminum alloy film exposed from the photoresist formed by the photolithography method is removed by the plasma etching method using chlorine gas, and then the photoresist is removed by the resist stripping solution to form the upper layer aluminum wiring 7 ( f).
A protective film is formed by applying a silicon nitride film 8 having a thickness of about 1 micron using ammonia and silane as source gases by the plasma CVD method (g). Although not shown in the figure, after this, the protective film at the wire bonding portion is opened.

[0003]

In the above-mentioned resist stripping method, generally, an organic solvent containing ABS (almol benzene sulfonic acid) P, phenol, etc. is added at about 100.degree.
The temperature is raised to, and the substrate is immersed for 5 to 10 minutes.

However, in this process, the problem that the electric insulation of the polyimide film is deteriorated often occurs.
Although the cause of this is not clear, a leak layer is generated on the surface of the polyimide, and as a result, a leak path of several tens to several hundreds MΩ in terms of layer resistance exists between the wirings, which leads to defective circuit operation of the LSI, resulting in a good product yield. This resulted in a significant decrease.

[0005]

According to a method of manufacturing a semiconductor device of the present invention, a substrate having a metal wiring layer formed on a surface of an interlayer insulating film made of a polyimide resin is treated with oxygen / carbon tetrafluoride.
A step of forming a second insulating film after etching the surface of the interlayer insulating film to 2000 angstroms or less by a plasma etching method using a sulfur hexafluoride gas alone or a mixed gas or a sputter etching method using an argon gas. I have it.

[0006]

The present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment in which the upper aluminum wiring is formed as shown in FIG. Next, in the plasma CVD apparatus as shown in FIG. 6 (g), the pressure in which the substrate 1 was put into the reactor and decompressed and then oxygen gas was introduced was set to about 1 Torr, and RF power of 2 kw, which is almost the same as the film growth, was applied to the 3 Approximately 500 minutes after processing the polyimide surface
Etch ~ 1000 angstroms. After that, evacuate once, then under normal conditions, ammonia,
A source gas such as silane is introduced to attach the silicon nitride film 8. S for cleaning the inside of the reactor
Fluorine gas such as F ₆ and NF ₃ and oxygen gas are plasma C
It has been introduced into the VD device and can be easily realized from an industrial point of view.

The second embodiment will be described with reference to FIG. As in the prior art, after forming the upper layer aluminum wiring 7 (f), the polyimide surface is treated with oxygen plasma at a pressure of 0.5 Torr for about 200 minutes for about 3 minutes using a barrel type plasma etching apparatus used as a resist dry removing apparatus. 500
Etch about angstrom. After this, a silicon nitride film is attached by using a plasma CVD device as in the conventional case (g). Further, there is no problem even if the surface of the substrate is washed with pure water before the film growth by the plasma CVD apparatus.

In addition to the above-mentioned methods, sufficient effects can be confirmed by using carbon tetrafluoride or carbon hexafluoride as an etching gas or using a mixed gas of them with oxygen gas.

It has also been confirmed that sputter etching using argon gas ions can be used instead of plasma etching. Furthermore, the effect does not change even if a silicon oxide / nitride film, a silicon oxide film, or a silicon phosphoric oxide film is applied as a protective film by the plasma CVD method.

[0011]

As described above, according to the present invention, it is possible to solve the leak failure on the surface of the polyimide interlayer insulating film by utilizing the existing equipment and to stably manufacture the multilayer wiring LSI with high yield. Has the effect that it can be manufactured at low cost.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a manufacturing process of a multilayer wiring technique for explaining a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a manufacturing process of a multilayer wiring technique for explaining a second embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a manufacturing process of a conventional multilayer wiring technique.

[Explanation of symbols] 1 substrate 2 lower layer aluminum wiring 3 polyimide film 4 photoresist 5 through hole portion 6 aluminum alloy film 7 upper layer aluminum wiring 8 silicon nitride film

Claims (2)

[Claims] 1. A semiconductor substrate having a metal wiring layer formed on a surface of an interlayer insulating film made of a polyimide resin is treated by a plasma etching method using an oxygen / carbon tetrafluoride / sulfur hexafluoride gas or a mixed gas, or argon. The surface of the inter-layer insulation film is removed by a sputter etching method using gas.
A method of manufacturing a semiconductor device, which comprises forming a second insulating film after etching to a thickness of 000 angstroms or less. 2. The second insulating film is a silicon nitride film, a silicon oxide / nitride film, a silicon oxide film, or a silicon phosphoric oxide film formed by using a plasma CVD method. A method for manufacturing a semiconductor device as described above.