A feature-to-wafer-scale model of etch-rate non-uniformity in deep reactive ion etching/

Deep Reactive Ion Etching (DRIE) is an inherently complex dry etching process commonly used in the semiconductor manufacturing industry. This work presents a new modeling approach to capture global etch rate variation in DRIE by integrating wafer- and feature-scale nonuniformity models that are grounded on an ion-neutral synergy model for etch rate. Our method focuses on diffusive transport and local depletion of Fluorine radicals above the wafer surface to facilitate integration of wafer- and feature-scale models. Our results show that the wafer-level model achieves a success comparable to that of other wafer-level models previously developed with an etch rate RMS error percentage between 2.1% and 8.2%. The coupled wafer- and feature-level model shows that the feature-level etch evolution substantially impacts the waferlevel Fluorine concentration and thereby modifies the wafer etch rate uniformity. Similarly, the wafer-level etch rate directly impacts the rate of feature-level etch evolution. The coupled model is observed to over-predict the feature etch depth by an amount that increases with time and decreases for larger features, thus suggesting that the over-prediction arises from our assumption of negligible Fluorine consumption at the feature sidewall. Within-wafer etch depth variation of high aspect ratio features is also over-predicted, likely due in part to the negligible sidewall Fluorine consumption assumed. Suggestions to improve all levels of the model are examined.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2010

Author dc:creator

• Diaz, Jaime O. (Jaime Oscar Diaz Villamil)

Advisor dc:contributor.advisor

• Duane S. Boning.

• Electrical Engineering and Computer Science.

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/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/61572

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/61572