DOE Patents title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Etching radical controlled gas chopped deep reactive ion etching

Abstract

A method for silicon micromachining techniques based on high aspect ratio reactive ion etching with gas chopping has been developed capable of producing essentially scallop-free, smooth, sidewall surfaces. The method uses precisely controlled, alternated (or chopped) gas flow of the etching and deposition gas precursors to produce a controllable sidewall passivation capable of high anisotropy. The dynamic control of sidewall passivation is achieved by carefully controlling fluorine radical presence with moderator gasses, such as CH.sub.4 and controlling the passivation rate and stoichiometry using a CF.sub.2 source. In this manner, sidewall polymer deposition thicknesses are very well controlled, reducing sidewall ripples to very small levels. By combining inductively coupled plasmas with controlled fluorocarbon chemistry, good control of vertical structures with very low sidewall roughness may be produced. Results show silicon features with an aspect ratio of 20:1 for 10 nm features with applicability to nano-applications in the sub-50 nm regime. By comparison, previous traditional gas chopping techniques have produced rippled or scalloped sidewalls in a range of 50 to 100 nm roughness.

Inventors:
; ;
Issue Date:
Research Org.:
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1107578
Patent Number(s):
8546264
Application Number:
11/421,958
Assignee:
The Regents of the University of California (Oakland, CA)
Patent Classifications (CPCs):
H - ELECTRICITY H01 - BASIC ELECTRIC ELEMENTS H01L - SEMICONDUCTOR DEVICES
DOE Contract Number:  
AC02-05CH11231
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING

Citation Formats

Olynick, Deidre, Rangelow, Ivo, and Chao, Weilun. Etching radical controlled gas chopped deep reactive ion etching. United States: N. p., 2013. Web.
Olynick, Deidre, Rangelow, Ivo, & Chao, Weilun. Etching radical controlled gas chopped deep reactive ion etching. United States.
Olynick, Deidre, Rangelow, Ivo, and Chao, Weilun. Tue . "Etching radical controlled gas chopped deep reactive ion etching". United States. https://www.osti.gov/servlets/purl/1107578.
@article{osti_1107578,
title = {Etching radical controlled gas chopped deep reactive ion etching},
author = {Olynick, Deidre and Rangelow, Ivo and Chao, Weilun},
abstractNote = {A method for silicon micromachining techniques based on high aspect ratio reactive ion etching with gas chopping has been developed capable of producing essentially scallop-free, smooth, sidewall surfaces. The method uses precisely controlled, alternated (or chopped) gas flow of the etching and deposition gas precursors to produce a controllable sidewall passivation capable of high anisotropy. The dynamic control of sidewall passivation is achieved by carefully controlling fluorine radical presence with moderator gasses, such as CH.sub.4 and controlling the passivation rate and stoichiometry using a CF.sub.2 source. In this manner, sidewall polymer deposition thicknesses are very well controlled, reducing sidewall ripples to very small levels. By combining inductively coupled plasmas with controlled fluorocarbon chemistry, good control of vertical structures with very low sidewall roughness may be produced. Results show silicon features with an aspect ratio of 20:1 for 10 nm features with applicability to nano-applications in the sub-50 nm regime. By comparison, previous traditional gas chopping techniques have produced rippled or scalloped sidewalls in a range of 50 to 100 nm roughness.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Oct 01 00:00:00 EDT 2013},
month = {Tue Oct 01 00:00:00 EDT 2013}
}

Works referenced in this record:

Profile evolution of Cr masked features undergoing HBr-inductively coupled plasma etching for use in 25 nm silicon nanoimprint templates
journal, January 2005

  • Olynick, Deirdre L.; Liddle, J. Alexander; Rangelow, Ivo W.
  • Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, Vol. 23, Issue 5
  • https://doi.org/10.1116/1.2050669

High resolution inductively coupled plasma etching of 30 nm lines and spaces in tungsten and silicon
journal, January 2000

  • Goodyear, Andrew L.; Mackenzie, Sinclair; Olynick, Deirdre L.
  • Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, Vol. 18, Issue 6
  • https://doi.org/10.1116/1.1326922

Nanoscale pattern transfer for templates, NEMS, and nano-optics
conference, February 2007


Dependences of bottom and sidewall etch rates on bias voltage and source power during the etching of poly-Si and fluorocarbon polymer using SF[sub 6], C[sub 4]F[sub 8], and O[sub 2] plasmas
journal, January 2004

  • Min, Jae-Ho; Lee, Gyeo-Re; Lee, Jin-kwan
  • Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, Vol. 22, Issue 3
  • https://doi.org/10.1116/1.1695338

Advanced time-multiplexed plasma etching of high aspect ratio silicon structures
journal, January 2002

  • Blauw, M. A.; Craciun, G.; Sloof, W. G.
  • Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, Vol. 20, Issue 6
  • https://doi.org/10.1116/1.1518018

Investigation of fluorocarbon plasma deposition from c‐C4F8 for use as passivation during deep silicon etching
journal, November 2004

  • Labelle, Catherine B.; Donnelly, Vincent M.; Bogart, Gregory R.
  • Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, Vol. 22, Issue 6
  • https://doi.org/10.1116/1.1810165

Investigation of in situ trench etching process and Bosch process for fabricating high-aspect-ratio beams for microelectromechanical systems
journal, January 2002

  • Kok, Kitt Wai; Yoo, Won Jong; Sooriakumar, K.
  • Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, Vol. 20, Issue 5
  • https://doi.org/10.1116/1.1501583

Dry etching with gas chopping without rippled sidewalls
journal, January 1999

  • Volland, B.; Shi, F.; Hudek, P.
  • Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, Vol. 17, Issue 6
  • https://doi.org/10.1116/1.591061

Method of anisotropically etching silicon
patent, March 1996


Absolute intensities of the vacuum ultraviolet spectra in a metal-etch plasma processing discharge
journal, November 1999

  • Woodworth, J. R.; Blain, M. G.; Jarecki, R. L.
  • Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, Vol. 17, Issue 6
  • https://doi.org/10.1116/1.582044

Profile simulation of gas chopping based etching processes
journal, January 2002

  • Volland, B. E.; Ivanov, Tzv.; Rangelow, I. W.
  • Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, Vol. 20, Issue 6
  • https://doi.org/10.1116/1.1520572

The Electron Charging Effects of Plasma on Notch Profile Defects
journal, April 1995


Critical tasks in high aspect ratio silicon dry etching for microelectromechanical systems
journal, July 2003


Substrate cooling efficiency during cryogenic inductively coupled plasma polymer etching for diffractive optics on membranes
journal, January 2001

  • Olynick, Deirdre L.; Anderson, Erik H.; Harteneck, Bruce
  • Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, Vol. 19, Issue 6
  • https://doi.org/10.1116/1.1414021