Production of isolation trenches between active regions during the manufacture of integrated circuits, especially DRAMs, comprises etching trenches filled with oxide in semiconductor substrate to isolate the active regions, and processing

摘要

Production of isolation trenches between active regions during the manufacture of integrated circuits, especially DRAMs, comprises etching trenches filled with an oxide in a semiconductor substrate (10) to isolate the active regions and form deep trenches (12) filled with polysilicon (14); forming a silicon nitride layer (18) on the surface of the substrate; covering the whole surface of the substrate and the polysilicon with a hard mask layer (20); and forming lateral isolation trenches next to the active regions. Preferred Features: The surface of the polysilicon in the trenches lies than the surface of the silicon nitride layer. The silicon nitride layer is removed by etching on bars between the trenches for a pair of storage capacitors.