JPS63173331A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To improve reliability resulting from the quality deterioration of a metallic wiring layer by adding an etching process by nonreactive ions materially shaving off a contaminant adhering on an insulating film and the surface of the metallic wiring layer through reactive etching to a conventional metallic wiring layer forming process. CONSTITUTION:A semiconductor wafer 3 and an aluminum wiring layer 4 are shaped through a conventional process. Argon ions are made to collide with an silicon oxide film 2 in approximately 500nm thickness and an aluminum wiring layer 4 in approximately 1mum thickness by using a plasma etching system and a thin silicon oxide film 2a and an aluminum wiring layer 4a are formed through physical isotropic sputtering. Ion beam etching by an inert gas causing anisotropic etching may also be used. An silicon nitride film 5 is shaped through the same process as the conventional process. The defective area ratio of aluminum due to corrosion to the overall area of the aluminum wiring layer 4 after a high-temperature acceleration reliability test for thirty min at a temperature of 500 deg.C of a semiconductor device is reduced to one tenth or less of the conventional process.

Description

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

[Conventional technology]

With the recent increase in the degree of integration of semiconductor ICs, their reliability requirements are increasing, and for this reason, microfabrication technology for forming metal wiring layers that guarantees high quality in manufacturing and on the market has become important.

FIGS. 2(a) and 2(b) are cross-sectional views of a semiconductor chip shown in order of steps for explaining a conventional method of manufacturing a semiconductor device.

As shown in FIG. 2(a), the semiconductor wafer 3 has a silicon oxide film 2 on the silicon wafer 1 containing impurity substances.
After forming the silicon oxide film 2, an opening is provided in the silicon oxide film 2 for electrical connection with the impurity layer described above.

Next, an aluminum layer is deposited on the semiconductor wafer 3, and then an aluminum wiring layer 4 is formed using a reactive ion etching method using a halogen compound such as carbon tetrachloride, and then a photoresist layer is formed using an organic solvent. Peel off.

Next, as shown in FIG. 2(b), a silicon nitride film 5 is formed to stabilize the surface.

Note that this silicon nitride film 5 also corresponds to a glabella insulating film in the case of a semiconductor device with multilayer wiring.

[Problem that the invention seeks to solve]

In the conventional semiconductor device manufacturing method described above, in the reactive ion etching process for forming the aluminum wiring layer 4, halogen or halogen compounds adhere to the surfaces of the silicon oxide film 2 and the aluminum wiring layer 4 of the semiconductor wafer 83. Furthermore, there was a problem in that the halogen compounds were not sufficiently removed in the subsequent Potregis 1 to layer peeling steps, and rather the halogen compounds in the organic solvent for peeling also adhered and remained as contaminants.

In particular, as the design of the metal wiring layer of recent semiconductor ICs progresses to miniaturization, contaminants inside the semiconductor device react with the wiring metal during the subsequent heat treatment process and in the market where it is used as an electronic circuit. As the corrosion progresses, a major problem has arisen in that it becomes a factor in quality problems such as disconnection and defects.

An object of the present invention is to provide a method for manufacturing a highly reliable semiconductor device by cleaning the surfaces of a semiconductor wafer and a metal wiring layer.

[Means for solving problems]

The method for manufacturing a semiconductor device of the present invention includes a step of forming a metal wiring layer on a semiconductor wafer having an upper insulating film using a reactive ion etching method, and adhering to the surface of the semiconductor wafer and the metal wiring layer. The method includes a step of non-reactive ion etching of the contaminated contaminants using a rare gas.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1A to 1C are cross-sectional views of a semiconductor chip shown in the order of steps for explaining an embodiment of the present invention.

First, as shown in FIG. 1(a), the semiconductor wafer 3 and the aluminum wiring layer 4 are respectively the same as the semiconductor wafer 3 and the aluminum wiring layer 4 of FIG. Formed during the process.

Next, as shown in FIG. 1(b), argon ions are applied to the silicon oxide film 2 with a thickness of about 500 nm and the aluminum interconnection layer 4 with a thickness of about 1 μm using a plasma etching apparatus to achieve physical isotropy. Then, a thin silicon oxide film 2a and an aluminum wiring layer 4a are formed by sputtering.

To give numerical values as an example of the removed film thickness, the silicon oxide film 2a has a thickness of 5 to 1100 nm, and the aluminum wiring layer 4a has a top surface of 10 to 200 nm and a side surface of about 5 to 1100 nm.

Furthermore, as shown in FIG. 1(c), a silicon nitride film 5 is formed in the same process as the conventional process explained in FIG. 2(b).

After the semiconductor device manufactured by the semiconductor device manufacturing method of the present invention was subjected to a high temperature accelerated reliability test at a temperature of 500° C. for 30 minutes, the aluminum wiring layer 4a inside the semiconductor device was tested.
Comparing the corrosion state of the aluminum wiring layer 4 with the corrosion state of the aluminum wiring layer 4 of a semiconductor device according to the conventional method, it was found that in the conventional method, the ratio of aluminum loss area due to corrosion to the total area of the aluminum wiring layer 4 was several percent, but in this method According to the example, the defective area ratio has become less than one-tenth of the conventional ratio.

In the above embodiment, an isotropic plasma etching apparatus using inert gas ions was used, but ion beam etching using an inert gas, which results in anisotropic etching, may also be used.

〔Effect of the invention〕

As explained above, according to the present invention, etching using non-reactive ions is used to physically remove contaminants attached to the surface of an insulating film and metal wiring layer by the conventional reactive etching process for forming a metal wiring layer. By adding this step to the conventional metal wiring layer forming process, there is an effect that the reliability of the semiconductor device, which is caused by quality deterioration of the metal wiring layer, can be significantly improved.

[Brief explanation of the drawing]

1(a) to 1(C) are cross-sectional views of a semiconductor chip shown in the order of steps for explaining one embodiment of the present invention, and FIG. 2(a)
> and (b) are cross-sectional views of a semiconductor chip shown in order of steps for explaining a conventional method of manufacturing a semiconductor device. 1... Silicon wafer, 2, 2a... Silicon oxide film, 3.3b... Semiconductor device wafer, 4, 4a...
...Aluminum wiring layer, 5...Silicon nitride film.

Claims (1)

[Claims] forming a metal wiring layer on a semiconductor wafer having an upper insulating film using a reactive ion etching method;
A method for manufacturing a semiconductor device, comprising the step of performing non-reactive ion etching on contaminants attached to the surfaces of the semiconductor wafer and the metal wiring layer using a rare gas.