Etching of high aspect ratio features in Si using SF 6/O 2/HBr and SF 6/O 2/Cl 2 plasma

Sergi Gomez, Rodolfo Jun Belen, Mark Kiehlbauch, Eray Aydil

Research output: Contribution to journalArticle

Abstract

We have investigated the etching of high aspect ratio holes (∼4 μm deep, ∼0.2 μm diameter) in silicon using plasmas maintained in mixtures of S F6, O2, and HBr or Cl2 gases. The etching experiments were conducted in a low pressure (25 mTorr), high density, inductively coupled plasma etching reactor with a planar coil. Visualization of the profiles with scanning electron microscopy is used in conjunction with plasma diagnostics such as optical emission and mass spectroscopies to understand the key factors that control the feature profile shape and etch rate. HBr addition to S F6 O2 mixture reduces the F-to-O ratio, increases sidewall passivation and reduces mask undercut. Addition of Cl2 to S F6 O2 discharge also decreases the F-to-O ratio, but Cl-enhanced F chemical etching of silicon significantly increases the mask undercut and lateral etching. In both S F6 O2 HBr and S F6 O2 Cl2 mixtures, reduction of O2 flow rate and subsequent increase of the halogen-to-O ratio eventually results in significant lateral etching because of the lack of oxygen required to form a siliconoxyhalide passivating film on the sidewalls.

Original languageEnglish (US)
Pages (from-to)1592-1597
Number of pages6
JournalJournal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
Volume23
Issue number6
DOIs
StatePublished - Nov 1 2005

Fingerprint

high aspect ratio
Aspect ratio
Etching
etching
Plasmas
Silicon
Masks
masks
Plasma diagnostics
Halogens
Plasma etching
plasma diagnostics
optical emission spectroscopy
Inductively coupled plasma
silicon
plasma etching
profiles
Passivation
halogens
passivity

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

Cite this

Etching of high aspect ratio features in Si using SF 6/O 2/HBr and SF 6/O 2/Cl 2 plasma. / Gomez, Sergi; Belen, Rodolfo Jun; Kiehlbauch, Mark; Aydil, Eray.

In: Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films, Vol. 23, No. 6, 01.11.2005, p. 1592-1597.

Research output: Contribution to journalArticle

@article{9b90b913377c43aeb9b4cd5d030ba87f,
title = "Etching of high aspect ratio features in Si using SF 6/O 2/HBr and SF 6/O 2/Cl 2 plasma",
abstract = "We have investigated the etching of high aspect ratio holes (∼4 μm deep, ∼0.2 μm diameter) in silicon using plasmas maintained in mixtures of S F6, O2, and HBr or Cl2 gases. The etching experiments were conducted in a low pressure (25 mTorr), high density, inductively coupled plasma etching reactor with a planar coil. Visualization of the profiles with scanning electron microscopy is used in conjunction with plasma diagnostics such as optical emission and mass spectroscopies to understand the key factors that control the feature profile shape and etch rate. HBr addition to S F6 O2 mixture reduces the F-to-O ratio, increases sidewall passivation and reduces mask undercut. Addition of Cl2 to S F6 O2 discharge also decreases the F-to-O ratio, but Cl-enhanced F chemical etching of silicon significantly increases the mask undercut and lateral etching. In both S F6 O2 HBr and S F6 O2 Cl2 mixtures, reduction of O2 flow rate and subsequent increase of the halogen-to-O ratio eventually results in significant lateral etching because of the lack of oxygen required to form a siliconoxyhalide passivating film on the sidewalls.",
author = "Sergi Gomez and Belen, {Rodolfo Jun} and Mark Kiehlbauch and Eray Aydil",
year = "2005",
month = "11",
day = "1",
doi = "10.1116/1.2049303",
language = "English (US)",
volume = "23",
pages = "1592--1597",
journal = "Journal of Vacuum Science and Technology A",
issn = "0734-2101",
publisher = "AVS Science and Technology Society",
number = "6",

}

TY - JOUR

T1 - Etching of high aspect ratio features in Si using SF 6/O 2/HBr and SF 6/O 2/Cl 2 plasma

AU - Gomez, Sergi

AU - Belen, Rodolfo Jun

AU - Kiehlbauch, Mark

AU - Aydil, Eray

PY - 2005/11/1

Y1 - 2005/11/1

N2 - We have investigated the etching of high aspect ratio holes (∼4 μm deep, ∼0.2 μm diameter) in silicon using plasmas maintained in mixtures of S F6, O2, and HBr or Cl2 gases. The etching experiments were conducted in a low pressure (25 mTorr), high density, inductively coupled plasma etching reactor with a planar coil. Visualization of the profiles with scanning electron microscopy is used in conjunction with plasma diagnostics such as optical emission and mass spectroscopies to understand the key factors that control the feature profile shape and etch rate. HBr addition to S F6 O2 mixture reduces the F-to-O ratio, increases sidewall passivation and reduces mask undercut. Addition of Cl2 to S F6 O2 discharge also decreases the F-to-O ratio, but Cl-enhanced F chemical etching of silicon significantly increases the mask undercut and lateral etching. In both S F6 O2 HBr and S F6 O2 Cl2 mixtures, reduction of O2 flow rate and subsequent increase of the halogen-to-O ratio eventually results in significant lateral etching because of the lack of oxygen required to form a siliconoxyhalide passivating film on the sidewalls.

AB - We have investigated the etching of high aspect ratio holes (∼4 μm deep, ∼0.2 μm diameter) in silicon using plasmas maintained in mixtures of S F6, O2, and HBr or Cl2 gases. The etching experiments were conducted in a low pressure (25 mTorr), high density, inductively coupled plasma etching reactor with a planar coil. Visualization of the profiles with scanning electron microscopy is used in conjunction with plasma diagnostics such as optical emission and mass spectroscopies to understand the key factors that control the feature profile shape and etch rate. HBr addition to S F6 O2 mixture reduces the F-to-O ratio, increases sidewall passivation and reduces mask undercut. Addition of Cl2 to S F6 O2 discharge also decreases the F-to-O ratio, but Cl-enhanced F chemical etching of silicon significantly increases the mask undercut and lateral etching. In both S F6 O2 HBr and S F6 O2 Cl2 mixtures, reduction of O2 flow rate and subsequent increase of the halogen-to-O ratio eventually results in significant lateral etching because of the lack of oxygen required to form a siliconoxyhalide passivating film on the sidewalls.

UR - http://www.scopus.com/inward/record.url?scp=31044445656&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=31044445656&partnerID=8YFLogxK

U2 - 10.1116/1.2049303

DO - 10.1116/1.2049303

M3 - Article

VL - 23

SP - 1592

EP - 1597

JO - Journal of Vacuum Science and Technology A

JF - Journal of Vacuum Science and Technology A

SN - 0734-2101

IS - 6

ER -