Formation of nanoporous SiO2 films with super-low dielectric constant by F2 laser deposition

Ryota Miyano, Toshifumi Kikuchi, Kaname Imokawa, Daisuke Nakamura, Hiroshi Ikenoue

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Citations (Scopus)


Ultra-large scale integrated circuits (ULSIs) have been continually scaled down according to Moore's law. This can improve their power consumption and operation frequency but not the RC delay of their interconnections; to this end, super low dielectric constant films are required. We propose a novel method to fabricate porous SiO2 films with a super low dielectric constant by F2 laser deposition. In this method, a quartz target is evaporated by F2 laser ablation in vacuum-chamber-controlled Ar partial pressure. The evaporated SiO2molecules are agglomerated in the vacuum, and the size of the SiO2 nanoparticles are controlled by the Ar partial pressure. Porous SiO2 films are formed on a Si-receiving substrate, which is placed in front of the quartz target. The pulse duration of the F2 laser was approximately 20 ns, and the repetition rate of laser shots was 100 Hz. The base pressure of the vacuum chamber was 5 × 10-3 Pa. Then, Ar gas was introduced into the vacuum chamber through a mass flow controller to control the Ar partial pressure. The dominant size of the SiO2 nanoparticles decreased from 1.5-2.0 nm to 1.0-1.5 nm with the Ar partial pressure decreasing from 20 Pa to 4.5 Pa. In addition, the relative dielectric constant k of the porous SiO2 film formed at an Ar partial pressure of 4.5 Pa was 2.8, which is lower than that of thermal SiO2 (k = 4.0). In addition, the leakage current of the nanoporous SiO2 film was almost equal to that of the thermal SiO2 film. From these results, we conclude that nanoporous SiO2films with a super low dielectric constant can be formed by F2 laser deposition.

Original languageEnglish
Title of host publicationSynthesis and Photonics of Nanoscale Materials XVI
EditorsAndrei V. Kabashin, David B. Geohegan, Jan J. Dubowski
ISBN (Electronic)9781510624566
Publication statusPublished - 2019
EventSynthesis and Photonics of Nanoscale Materials XVI 2019 - San Francisco, United States
Duration: Feb 2 2019Feb 3 2019

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceSynthesis and Photonics of Nanoscale Materials XVI 2019
Country/TerritoryUnited States
CitySan Francisco

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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