Ultrahigh selective etching of Si3 N4 films over Si O2 films for silicon nitride gate spacer etching

Sunghoon Lee, Jinho Oh, Kyumin Lee, Hyunchul Sohn

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

The process window for the high etching selectivity of silicon nitride to silicon oxide was investigated in C F4 /C H4 inductively coupled plasma. This work showed that the etching selectivity could be controlled by modulating the thickness of the fluorocarbon film with the flow rates of C H4 gas. The carbon content in the fluorocarbon by-product layers on the etched films was observed to play a critical role in determining the etching selectivity of silicon nitride to silicon oxide. The increase in the carbon content in the fluorocarbon films with increasing C H4 gas caused the etch rates of both silicon oxide and silicon nitride films to be reduced, eventually leading to the etch stops. The minimum effective thickness of the fluorocarbon films was estimated to be 20 Å for the etch stop. The infinite etching selectivity of the silicon nitride to the silicon oxide on the blanket wafers could be achieved for the C H4 flow rate above 30 SCCM (SCCM denotes cubic centimeters per minute at STP) for the C F4 flow rate of 10 SCCM. N F3 /C H4 and S F6 /C H 4 plasma showed etch behavior similar to C F4 /C H 4 plasma.

Original languageEnglish
Pages (from-to)131-137
Number of pages7
JournalJournal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures
Volume28
Issue number1
DOIs
Publication statusPublished - 2010 Mar 19

Fingerprint

Silicon nitride
silicon nitrides
Fluorocarbons
spacers
fluorocarbons
Silicon oxides
Etching
silicon oxides
etching
selectivity
flow velocity
Flow rate
Plasmas
Carbon
blankets
carbon
Inductively coupled plasma
Gases
gases
nitrides

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Electrical and Electronic Engineering

Cite this

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title = "Ultrahigh selective etching of Si3 N4 films over Si O2 films for silicon nitride gate spacer etching",
abstract = "The process window for the high etching selectivity of silicon nitride to silicon oxide was investigated in C F4 /C H4 inductively coupled plasma. This work showed that the etching selectivity could be controlled by modulating the thickness of the fluorocarbon film with the flow rates of C H4 gas. The carbon content in the fluorocarbon by-product layers on the etched films was observed to play a critical role in determining the etching selectivity of silicon nitride to silicon oxide. The increase in the carbon content in the fluorocarbon films with increasing C H4 gas caused the etch rates of both silicon oxide and silicon nitride films to be reduced, eventually leading to the etch stops. The minimum effective thickness of the fluorocarbon films was estimated to be 20 {\AA} for the etch stop. The infinite etching selectivity of the silicon nitride to the silicon oxide on the blanket wafers could be achieved for the C H4 flow rate above 30 SCCM (SCCM denotes cubic centimeters per minute at STP) for the C F4 flow rate of 10 SCCM. N F3 /C H4 and S F6 /C H 4 plasma showed etch behavior similar to C F4 /C H 4 plasma.",
author = "Sunghoon Lee and Jinho Oh and Kyumin Lee and Hyunchul Sohn",
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Ultrahigh selective etching of Si3 N4 films over Si O2 films for silicon nitride gate spacer etching. / Lee, Sunghoon; Oh, Jinho; Lee, Kyumin; Sohn, Hyunchul.

In: Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures, Vol. 28, No. 1, 19.03.2010, p. 131-137.

Research output: Contribution to journalArticle

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AU - Oh, Jinho

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