JPH0362520A - Plasma cleaning method - 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 Application Field] The present invention relates to a plasma cleaning method, and particularly to a plasma cleaning method suitable for cleaning after barrier metal is etched.

[Conventional technology]

Conventional cleaning methods include, for example, Japanese Patent Application Laid-Open No. 1983-1999, which is a cleaning method after etching aluminum.
As described in Publication No. 250185@, an oxidizing gas is introduced into the processing chamber after treatment to oxidize the residual reaction products, and then a fluorine-containing gas is introduced to generate plasma to remove the residual reaction products. There is an effective way to remove it.

[Problem to be solved by the invention]

The above conventional technology does not take into consideration the cleaning of residual reaction products remaining in the chamber when a material other than the M alloy film, such as a barrier metal, is etched in the same chamber after etching the M alloy film. Ta. After performing such kneeing, products other than the residual reaction products remaining during etching of the M alloy film also remain, so there is a problem that the conventional method cannot perform sufficient cleaning. there were.

SUMMARY OF THE INVENTION An object of the present invention is to provide a plasma cleaning method capable of removing reaction products remaining in a processing chamber when an M alloy film and a barrier metal are etched using the same processing chamber.

[11! Means for Solving the Problem] In order to achieve the above object, a combination of discharge using a chlorine-containing gas and discharge using a fluorine-containing gas is performed.

[For production]

By turning the gas containing chlorine into plasma, some of the reaction products remaining from etching the M alloy film and the reaction products remaining from etching the barrier metal are removed, and by turning the gas containing fluorine into plasma. , the remaining reaction products are removed. This makes it possible to remove residual reaction products from multiple treatments within the same treatment chamber.

〔Example〕

An embodiment of the present invention will be described below.

The object to be etched has a structure in which the upper layer is an M alloy film and the lower layer is a barrier metal. For example, the M alloy film is a ke-S i -Cu film, and the barrier metal is TiW. .

It is considered that ke5i-Cui was etched with a gas mainly composed of chlorine, and the reaction products of M remained in the processing chamber. It is also believed that TtWg is etched mainly using fluorine-based gas, and the reaction products of Ti and W products remain in the processing chamber together with the reaction products of M products. By repeating these etching processes, for example, after processing about 10 wafers, these residual reaction products will be removed by the air temperature in the quartz belljar in the processing chamber and parts around the electrodes. It will appear.

When cleaning such residual reaction products, gas containing chlorine, for example, C12 gas only, C12+
B C1s, + HC1, etc. are turned into plasma and plasma cleaning is performed for 5 minutes, and then a gas containing fluorine, for example, S Fs * S F, 02 F6
etc., and perform plasma cleaning for about 5 minutes. As a result, for example, in Clz plasma cleaning, M products and Ti products are ke Cl 2
In SF6 plasma cleaning, W products are removed as WF2.

As described above, according to this example, the products of M and Ti can be removed by discharging a gas containing chlorine, and the products of W can be removed by discharging a gas containing fluorine. This has the effect that the inside of the processing chamber can be cleaned after the etching process.

In this example, l'J -8l- is used as the M alloy film.
Although cuM is mentioned, M-84 film, MC, etc. may also be used.

In addition, although Ti film was mentioned as a barrier metal, MoS
It may be an i film, a WSI film, a Ti film, a TiN film, an α-8i film, or the like.

In addition, in this example, cleaning was performed by discharging a gas containing fluorine after discharging a gas containing chlorine.
These discharges may be performed alternately.

Furthermore, in this example, the discharge of gas containing chlorine was carried out for about 5 minutes.
Although the discharge of the fluorine-containing gas is approximately 5 minutes, the time ratio of these discharges depends on the component ratio of the barrier metal, for example, Ti.
It is even more effective to change the ratio of Ti and W components in Wi.

〔Effect of the invention〕

Claims (1)

[Claims] 1. A method for cleaning the inside of a processing chamber when an Al alloy film and a barrier metal are plasma etched using the same processing chamber, characterized in that a discharge using a gas containing chlorine and a discharge using a gas containing fluorine are performed in combination. Cleaning method.