Etching kinetics and surface roughening of polysilicon and dielectric materials in inductively coupled plasma beams

Plasma etching processes often roughen the feature sidewalls forming anisotropic striations. A clear understanding of the origin and control of sidewall roughening is extremely desirable, particularly at the gate level where variations in line width can adversely impact the electrical performance of the device. In addition, at the back end, feature sidewall roughness of the dielectric materials might degrade the resolution of contacts, interfere with the deposition of conformal liner materials, and make the process integration challengeable. In an inductively coupled plasma apparatus, the etching behavior on real feature sidewalls was simulated by etching blank films at grazing ion bombardment angles. The angular etching yields of polysilicon and dielectric materials in Ar, C12/Ar, and C4F8/Ar plasma beams were studied as a function of ion bombardment energy, ion bombardment angle, etching time, plasma pressure, and plasma composition. Interestingly, the effective neutral-to-ion flux ratio was the primary factor influencing the etching yield. A typical sputtering angular yield curve, with a peak around 600 off-normal angle, was formed at non-saturated etching regime, while an ion-enhanced-etching angular yield curve peaked around 650 was observed in the saturated etching regime.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Chemical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2007

Author dc:creator

• Yin, Yunpeng, Ph. D. Massachusetts Institute of Technology

Advisor dc:contributor.advisor

• Herbert H. Swain.

• Chemical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/38973
• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Identifier URI

http://dspace.mit.edu/handle/1721.1/38973

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/38973