Chemical modification of subcritical water for the dissolution of Si3N4 layer in the fabrication of microelectronic devices

Changjin Son, Yuseok Lee, Sangwoo Lim

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1 Citation (Scopus)

Abstract

Subcritical water was used to selectively remove Si3N4 layers in the 3D NAND fabrication. Various fluorine compounds were added to subcritical water. When sulfonyl fluoride-based additives were added to subcritical water, the dissolution of Si3N4 was accelerated by F-, and the Si3N4-to-SiO2 removal selectivity increased owing to the high [F-]/[HF2-] ratio and low OH- concentration. Furthermore, the addition of H2SiO3 to the subcritical water resulted in selective and uniform Si3N4 removal without the loss of SiO2 layers in the 128-layer Si3N4/SiO2 stack structure. However, the addition of ammonium fluoride compounds to subcritical water could not achieve selective removal of Si3N4. The addition of HCl to the ammonium fluoride-containing subcritical water suppressed the dissolution of Si and SiO2. Further addition of H2SiO3 and optimization of the additive concentrations led to selective and uniform Si3N4 removal in the 128-layer Si3N4/SiO2 stack structure without the loss of the Si substrate and SiO2 layers.

Original languageEnglish
Article number105699
JournalJournal of Supercritical Fluids
Volume189
DOIs
Publication statusPublished - 2022 Oct

Bibliographical note

Publisher Copyright:
© 2022 Elsevier B.V.

All Science Journal Classification (ASJC) codes

  • General Chemical Engineering
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

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