Organic low K dielectric etch with NH3 chemistry

Details Organic low K dielectric etch with NH3 chemistry Organic low K dielectric etch with NH3 chemistry

2001-01-26

2004-06-01

Vinh, Lan (Department: 1765)

Semiconductor device manufacturing: process

Chemical etching

Vapor phase etching

C438S710000, C438S712000, C438S720000, C216S037000, C216S067000

Reexamination Certificate

active

06743732

ABSTRACT:

BACKGROUND OF INVENTION
1) Field of the Invention
This invention relates generally to fabrication of semiconductor devices and more particularly to the etching of organic low-k dielectric layers and particularly an etch process for organic low K layers that uses a ammonia based chemistry (e.g., pure ammonia or ammonia with (H
2
or N
2
))
2) Description of the Prior Art
Traditional etch chemistry for the organic low-k material is N
2
related chemistry, such a s N
2
/O
2
and H
2
/H
2
etc. The excellent physical profile of the damascene structure can be obtained by N
2
/H
2
chemistry with a lower etch rate, compared to N
2
/O
2
chemistry. However, it is very likely to get a bowing sidewall profiles (e.g., non-vertical sidewalls) by N
2
/O
2
chemistry.
The importance of overcoming the various deficiencies noted above is evidenced by the extensive technological development directed to the subject, as documented by the relevant patent and technical literature. The closest and apparently more relevant technical developments in the patent literature can be gleaned by considering U.S. Pat. No. 6,071,815 (Kleinhenz et al.) that shows a silicon oxide layer etch that uses HF and ammonia in combination with other gases.
U.S. Pat. No. 5,897,377 (Suzuki) shows a surface treatment etch.
U.S. Pat. No. 5,972,235 (Brigham et al.) shows a low-k etch.
U.S. Pat. No. 6,063,712 (Gilton et al.) teaches an oxide etch using ammonia a fluorine containing compound and a boron containing compound.
However, further improvement is needed to etch organic low-K materials.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a method for etching low-k dielectric layers.
It is an object of the present invention to provide a method for etching low-k dielectric layers that uses an ammonia based chemistry.
It is an object of the present invention to provide a method for etching low-k dielectric layers that uses an pure ammonia or NH
3
/H
2
or NH
3
/N
2
etch gasses plus optionally CO and/or O
2
.
To accomplish the above objectives, the present invention provides a method which is characterized as follows. An organic low k dielectric layer is formed over a substrate. A resist pattern is formed over the low k dielectric layer. The resist pattern has an opening.
Using the invention's etch process, the organic low k dielectric layer is etched through the opening in an etch mask. The invention's etch process comprise a NH
3
containing plasma etch (optionally with H
2
or N
2
).
The invention's NH
3
containing plasma etch etches Low k materials unexpectedly well. The invention's NH
3
only etch had a 30 to 80% higher etch rate than conventional N
2
/H
2
etches of low-k materials like Silk™.
Additional objects and advantages of the invention will be set forth in the description that follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of instrumentalities and combinations particularly pointed out in the append claims.


REFERENCES:
patent: 5897377 (1999-04-01), Suzuki
patent: 5972235 (1999-10-01), Brigham et al.
patent: 6051503 (2000-04-01), Bhardwaj et al.
patent: 6063712 (2000-05-01), Gilton et al.
patent: 6071815 (2000-06-01), Kleinhenz et al.
patent: 6080529 (2000-06-01), Ye et al.
patent: 6191043 (2001-02-01), McReynolds
patent: 6245662 (2001-06-01), Naik et al.
patent: 6326302 (2001-12-01), Joubert et al.
patent: 6436808 (2002-08-01), Ngo et al.
patent: 6455431 (2002-09-01), Hsieh et al.
patent: 6458516 (2002-10-01), Ye et al.

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