Front-end-of-line device structure and method of forming such a front-end-of-line device structure

A device, comprising:

• a semiconductor substrate having a semiconductor-on-insulator (SOI) configuration, comprising a semiconductor layer, a semiconductor base substrate and a buried insulating material layer interposed between said semiconductor layer and said semiconductor base substrate, and said semiconductor substrate having a trench formed therein, said trench at least partially extending into said semiconductor base substrate;
• and
• a trench isolation structure formed in said trench, wherein said trench isolation structure comprises:
• first and second insulating liners formed adjacent inner surfaces of said trench, wherein said first insulating liner is in direct contact with said inner surfaces of said trench and said second insulating liner is formed directly on said first insulating liner;
• and
• first and second insulating filling materials filling said trench, wherein said second insulating filling material is formed on said first and second insulating liners and said first insulating filling material in said trench and said second insulating filling material directly contacts an upper surface portion of said first insulating liner adjacent said buried insulating layer.

A method, comprising:

• etching a first trench into a semiconductor substrate;
• consecutively forming first and second insulating liners in said first trench;
• forming a first insulating filling material on said first and second insulating liners in said first trench;
• performing a recessing process after said first insulating filling material is formed, wherein an upper portion of said first insulating filling material is removed and an upper portion of said second insulating liner is exposed;
• performing a pullback etching process, wherein said exposed upper portion of said second insulating liner material is removed and an upper surface portion of said first insulating liner is exposed;
• and
• filling said first trench with a second insulating filling material, wherein said exposed upper surface portion of said first insulating liner is directly contacted by said second insulating filing material.