Process flow for sacrificial collar with poly mask

The present invention relates generally to the fabrication of semiconductor integrated circuits (IC's), and more particularly to the fabrication of memory IC's. A process for forming a sacrificial collar () on the top portion of a deep trench (). A nitride layer () is deposited within the...

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Bibliographic Details
Main Authors Tews, Helmut Horst, Kudelka, Stephan, McStay, Irene
Format Patent
LanguageEnglish
Published 01.10.2002
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Summary:The present invention relates generally to the fabrication of semiconductor integrated circuits (IC's), and more particularly to the fabrication of memory IC's. A process for forming a sacrificial collar () on the top portion of a deep trench (). A nitride layer () is deposited within the trench (). A semiconductor layer () is deposited over the nitride layer (). A top portion of the semiconductor layer () is doped to form doped semiconductor layer (). Undoped portions () of the semiconductor layer are removed, and the doped semiconductor layer () is used to pattern the nitride layer (), removing the lower portion of nitride layer () from within deep trenches () and leaving a sacrificial collar () at the top of the trenches ().