High density large area hydrogen plasma by hollow cathode plasma array

Hydrogen plasma becomes an alternative to the conventional oxygen plasma in stripping photoresist in the next generation semiconductor processing because the conventional oxygen plasma is known to degrade ultralow dielectric constant films by depleting carbons from the films. An array of hollow cath...

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Bibliographic Details
Published in:Surface & coatings technology 2010-11, Vol.205 (5), p.1532-1535
Main Authors: Cho, Jeonghee, Yang, Jack, Park, Haejung, Park, Se-Geun
Format: Article
Language:English
Subjects:
Arrays
Chambers
Cross-disciplinary physics: materials science
rheology
Exact sciences and technology
High density
Holes
Hollow cathode
Hydrogen plasma
Low-k dielectric films
Materials science
Oxygen plasma
Photoresist stripping
Photoresists
Physics
Semiconductors
Stripping
Surface treatments
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Summary:Hydrogen plasma becomes an alternative to the conventional oxygen plasma in stripping photoresist in the next generation semiconductor processing because the conventional oxygen plasma is known to degrade ultralow dielectric constant films by depleting carbons from the films. An array of hollow cathode plasma is designed to have uniform and high density hydrogen plasma. From many combinations of cavity size and distribution, it is found that cylindrical ceramic cavity with 6 mm inner diameter, 10 mm depth and 30 mm spacing between neighboring cavities shows the widest process window. Nineteen cavities are engraved into the cathode plate of 200 mm diameter. Ceramic cavities are needed to survive against energetic ion bombardment. Dependence of the stripping rate on mixture ratio of N 2/H 2, gas flow rate, chamber pressure and RF power is investigated, and we have found that a stripping rate of more than 260 nm/min with 7% uniformity can be achieved when chamber pressure is 213 Pa, gas flow rate 10000 sccm, N 2/H 2 mixture ratio of 3:7 and RF power 2.5 KW. This high density hydrogen plasma in the order of 10 11/cm 3can be a very effective method of photoresist stripping in the dual damascene process of copper metal and low-k dielectrics where oxygen plasma cannot be used.
ISSN:0257-8972
1879-3347
DOI:10.1016/j.surfcoat.2010.08.090