| 摘要 |
PURPOSE: A reverse etch-back method for improving STI(Shallow Trench Isolation) processing is provided to reduce the fabrication cost of a mask by forming a reverse mask by reverse exposure. CONSTITUTION: A reverse mask having a field region(FR) is formed by using reverse tone exposing of an active mask to cover an active region(AR). An oxide layer(24) for gap-filling is etched to have a gentle slope at the boundary of the active region by reverse etch-back processing using the reverse mask so as to improve uniformity of CMP of the oxide layer. At this time, mixed gases containing CF4 and CHF3 are used as the etching gas.
|
