Method of cleaning a dual damascene structure

Details Method of cleaning a dual damascene structure Method of cleaning a dual damascene structure

2001-04-24

2004-05-11

Kornakov, M. (Department: 1746)

Cleaning and liquid contact with solids

Processes

Using sequentially applied treating agents

C134S001200, C134S002000, C134S003000, C134S031000, C134S902000, C216S067000, C216S078000, C216S081000, C216S095000, C216S108000, C216S109000, C438S906000

Reexamination Certificate

active

06733597

ABSTRACT:

CROSS-REFERENCE TO RELATED APPLICATION
This application claims the priority benefit of Taiwan application serial no. 90109100, filed on Apr. 17, 2001.
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to a cleaning method of a semiconductor structure. More particularly, the present invention relates to a cleaning method of a dual damascene structure.
2. Description of Related Art
When using a dual damascene structure in multilevel metal interconnects, the reliability and process ability of the device are increased. A copper conducting wire is generally used in this process to decrease the resistance of the conducting wire and increase the speed and quality of the integrated circuit device. After the device achieves high integration, using a dielectric layer having a low dielectric constant (low-k) to manufacture the dual damascene structure has gradually become the major technique in the semiconductor industry.
FIG. 1
illustrates a cross-sectional view of a conventional dual damascene structure.
Referring to
FIG. 1
, a metal layer
102
, a cap layer
104
and a dielectric layer
106
are formed on a substrate
100
. A dual damascene opening
108
is formed by etching the dielectric layer
106
and cap layer
104
. The metal layer
102
serves as an etching stop layer, and a part of the surface of the metal layer
102
is exposed. The material of the cap layer
104
is silicon nitride. This etching process produces a lot of polymer residue that remains on the profile of dual damascene opening
108
and the surface of the metal layer
102
. Therefore, a cleaning step can remove the polymer residue and metal oxide on the profile of the dual damascene opening
108
and the surface of the metal layer
102
before a second metal layer fills in the dual damascene opening
108
. In the final step, the second metal layer fills in the dual damascene opening
108
.
In the conventional cleaning method of the dual damascene opening, an amine-based organic solvent first cleans the dual damascene opening
108
, followed by an argon sputtering step to bombard the metal oxide for removing the polymer residue before the second metal layer fills in the dual damascene opening
108
. However, the conventional method cannot completely remove the metal oxide from the surface of the metal layer
102
. In another conventional cleaning method of dual damascene opening, an amine-based organic solvent cleans as the opening similar to the previous description, and then hydrogen gas (H
2
) is used to deoxidize the metal oxide for cleaning and removing the polymer residue and the metal oxide. The second cleaning method can completely remove the polymer residues and metal oxide, but the hydrogen also reacts on the dielectric layer
106
, and a bow shaped recess
110
is formed, which damages the profile of the dual damascene
108
.
SUMMARY OF THE INVENTION
The invention provides a cleaning method of a dual damascene to remove the polymer residue and the metal oxide.
The invention also provides a cleaning method of a dual damascene to reduce the via resistance and prevent erosion of the metal layer.
The invention also provides a cleaning method of a dual damascene to prevent further damage on the profile of the dual damascene.
As embodied and broadly described herein, the invention provides a cleaning method of a dual damascene. A first metal layer, a cap layer and a dielectric layer are formed in sequence on a substrate, and then a dual damascene opening is formed in the dielectric layer and the cap layer to expose the surface of the first metal layer. There are two types of cleaning steps after etching. The first method uses a fluorine based organic solvent to clean the dual damascene opening. An alternative cleaning method for the dual damascene opening first uses a hydrogen peroxide based solvent at a high temperature, followed by a hydrofluoric acid solvent cleaning step. Then, an argon gas plasma is sputtered to clean the dual damascene opening before a second metal layer fills in the dual damascene opening.
The cleaning method of this invention is more efficient to remove the polymer residue on the dielectric layer and the metal oxide on the metal layer, and reduces the via resistance in the dual damascene.
The cleaning method of this invention also can prevent further damage on the profile of the dual damascene opening.
The cleaning method of this invention also can prevent the erosion of the metal layer.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.


REFERENCES:
patent: 5320709 (1994-06-01), Bowden et al.
patent: 5670421 (1997-09-01), Nishitani et al.
patent: 5904560 (1999-05-01), Brumley
patent: 6187682 (2001-02-01), Denning et al.
patent: 6232237 (2001-05-01), Tamaoka et al.
patent: 6293848 (2001-09-01), Fang et al.
patent: 6361712 (2002-03-01), Honda et al.
patent: 6440873 (2002-08-01), Wu et al.
patent: 0 90111160 (1998-08-01), None

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