On-wafer monitoring of charge accumulation and sidewall conductivity in high-aspect-ratio contact holes during Si O2 etching process

Butsurin Jinnai, Toshiyuki Orita, Mamoru Konishi, Jun Hashimoto, Yoshinari Ichihashi, Akito Nishitani, Shingo Kadomura, Hiroto Ohtake, Seiji Samukawa

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

The authors investigated charge accumulation in high-aspect-ratio contact-hole structures by using the new on-wafer monitoring device they fabricated on a Si substrate of 8 in. in diameter by using a conventional production process for semiconductor devices. The device has high-aspect-ratio contact-hole structures that are comparable with the practical interconnect structures of recent dynamic random access memory devices. In this article they discuss charge accumulation and the electric conductivity of fluorocarbon polymer deposited on the sidewall in high-aspect-ratio contact holes during plasma etching processes. They also monitored the charge accumulation during pulse-time-modulated (TM) plasma etching of high-aspect-ratio Si O2 contact-hole structures and found that the charge accumulation potential between the top and bottom of the contact-hole structures increased with the aspect ratio of the contact holes. Even in high-aspect-ratio contact holes the charge accumulated during TM plasma exposure was less than that accumulated during the conventional continuous-wave plasma exposure. The electrical conductivity of the fluorocarbon polymer deposited on the sidewall was increased by ion bombardment and was lower in high-aspect-ratio contact holes than in low-aspect-ratio contact holes. The new on-wafer monitoring device is a very effective tool for investigating local charge accumulation during the etching of device structures.

Original languageEnglish
Pages (from-to)1808-1813
Number of pages6
JournalJournal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures
Volume25
Issue number6
DOIs
Publication statusPublished - 2007

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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