| abstract |
A method for fabricating a trench isolation structure includes the steps of first forming a ruthenium oxide layer on a substrate. Thereafter, a hard mask was formed on the pad yttria layer using a reaction gas containing Hexa-Chloro-Disilane (HCD). Next, an etching process is performed to form trenches in the hard mask layer, the pad oxide layer, and the substrate. A non-phosphoric acid wet process is then performed to remove a portion of the hard mask layer. After the ceria filling process, the remaining hard mask layer is removed. |