On the scaling of rf and dc self-bias voltages with pressure in electronegative capacitively coupled plasmas

Agarwal, Ankur; Dorf, Leonid; Rauf, Shahid; Collins, Ken

doi:doi:10.1116/1.3676182

Volume/Page
Keyword
DOI
Citation
Advanced

Volume: Page/Article:

Search Content Type

article doi:

Citation:

You are not logged in to this journal. Log In

Journal of Vacuum Science & Technology A / Volume 30 / Issue 2 / Plasma Science and Technology

Previous Article | Next Article

J. Vac. Sci. Technol. A 30, 021303 (2012); http://dx.doi.org/10.1116/1.3676182 (11 pages)

On the scaling of rf and dc self-bias voltages with pressure in electronegative capacitively coupled plasmas

Ankur Agarwal, Leonid Dorf, Shahid Rauf, and Ken Collins

Applied Materials Inc., 974 E. Arques Avenue, M/S 81312, Sunnyvale, California 94085

View Map

(Published online 12 January 2012)

Abstract

References (38)

Article Objects (15)

Alerts
- Alert Me When Cited
- Alert Me When Corrected
Tools
Share
- Email Abstract
- Connotea
- CiteULike
- del.icio.us
- BibSonomy
- Tweet this Article
- Add to Facebook

Full Text: Read Online (HTML) | Download PDF | Rent Article | Buy PDF (US$28) | View Cart

Higher gas densities and lower diffusion losses at higher operating pressures typically lead to increased charged species densities (and hence flux) for a constant power deposition in capacitively coupled plasmas (CCP). As a result, one would expect that the bias radio-frequency (rf) voltage required to deposit a given power in a CCP reactor decreases with increasing operating pressure. These observations may not hold true in multiple frequency CCPs, commonly used for dielectric etching in microelectronics fabrication, due to nonlinear interactions between the rf sources. Wafer-based measurements of the rf and self-generated direct current (dc) bias voltages in a dual-frequency capacitively coupled electronegative plasma were made, which indicate that the rf and dc voltages vary nonmonotonically with pressure. These experimental results are presented in this paper and a computational plasma model is used to explain the experimental observations for varying 60 MHz and 13 MHz powers in the Ar/CF₄/CHF₃ plasma over a pressure range of 25 to 400 mTorr. The authors found that while the ion density increases with pressure, the increase is most dominant near the electrode with the high frequency source (60 MHz). The rf and dc bias voltages are ultimately influenced by both charged species density magnitudes and spatial profiles.

ACKNOWLEDGMENT

The authors would like to thank Mike Chafin for his help in experimental measurements.

Article Outline

INTRODUCTION
EXPERIMENTAL MEASUREMENTS
DESCRIPTION OF THE MODEL
EFFECT OF PRESSURE ON RF AND DC VOLTAGES
CONCLUDING REMARKS

View more related articles.

KEYWORDS and PACS

Keywords

argon, electronegativity, gas mixtures, plasma density, plasma diagnostics, plasma pressure, plasma sources, plasma transport processes, sputter etching

PACS

52.25.Fi

Transport properties
52.50.Dg

Plasma sources
52.70.Gw

Radio-frequency and microwave measurements

History

Received 16 August 2011
Accepted 30 November 2011
Published online 12 January 2012

Digital Object Identifier

http://dx.doi.org/10.1116/1.3676182

PUBLICATION DATA

ISSN

0734-2101 (print)

1520-8559 (online)

Publisher

American Vacuum Society

For access to fully linked references, you need to log in.

Figures (14) Tables (1)

Access to article objects (figures, tables, multimedia) requires a subscription; log in to view available files.
(Access to supplementary files, where available, is free for this journal.)