Patent ID: 8765575
Filing Date: 2014-07-01
Classification: H01L

Abstract:
1. A method for forming a trench filled with an insulator in a wafer comprising a silicon support coated with a first silicon oxide layer and with a single-crystal silicon layer, the trench crossing the silicon and silicon oxide layers and penetrating into the support, this method comprising the steps of: forming on the silicon layer a second silicon oxide layer and a first silicon nitride layer, masking and etching to form the trench while leaving in place the second oxide layer and the first nitride layer outside of the trench, and performing a first oxidizing processing to form a third silicon oxide layer on the exposed silicon surfaces; performing a second oxidizing processing in the presence of an oxygen plasma to form on the exposed surfaces of the first silicon nitride layer a fourth silicon oxide layer; depositing a second silicon nitride layer and filling the trench with silicon oxide; and removing the upper portion of the structure until the upper surface of the silicon layer is exposed.