Patent ID: 8501607
Filing Date: 2013-08-06
Classification: H01L

Abstract:
1. A method comprising: forming pillars on a silicon (Si) substrate, the pillars comprising tetraethyl orthosilicate (TEOS) on polysilicon (poly-Si); conformally depositing a first TEOS liner over the entire silicon substrate; etching the first TEOS liner and Si substrate through the pillars, forming first trenches; filling the first trenches and spaces between the pillars with an oxide; removing the TEOS from the pillars and the oxide therebetween; removing the poly-Si; conformally depositing a second TEOS liner over the entire Si substrate; etching the second TEOS liner and Si between the oxide, forming second trenches having a different depth than the first trenches; filling the second trenches with oxide; removing the oxide and the first and second TEOS liners down to an upper surface of the Si substrate; and recessing the oxide below the upper surface of the Si substrate.