Patent ID: 6498061
Filing Date: 2002-12-24
Classification: H01L

Abstract:
In a process for fabricating a mask in a semiconductor deep trench structure filled with trench fill material having a top surface, the steps comprising:forming a barrier layer covering the top surface of the trench fill material, depositing a thin film masking layer over the barrier layer, performing an angled implant into the thin film masking layer, stripping undoped portions of the thin film masking layer from the deep trench leaving a window through the thin film masking layer leaving an exposed area of the barrier layer below the window, stripping the exposed area of the barrier layer which lies below the window through the thin film masking layer from the structure, thereby exposing a portion of the trench fill material surface and leaving the remainder of the barrier layer exposed, oxidizing the exposed portion of the trench fill material to form a self-aligned mask, and stripping the remainder of the barrier layer leaving the self-aligned mask whereby overlay problems are avoided by forming a self-aligned mask.