| 摘要 |
PURPOSE: To form a highly reliable contact hole in a memory cell in a self- aligning way by removing a side wall layer between gate electrodes with a thick film in a memory cell section and forming thin side wall layers on the side walls of the gate electrodes with a narrow space in the section. CONSTITUTION: After a buried insulating layer 11 is formed between gate electrodes 4 and 4a arranged at a small distance in the memory cell section of a silicon substance, a deep diffusion layer 8b is formed by combining heat treatment and ion implantation by using a resist mask 12 for ion implantation. Them, an interlayer insulating film 13 and resist mask 14 for contact hole are formed in prescribed shapes. After forming the mask 14, a contact hole 15 is formed by etching the insulating film 13 and buried insulating layer 11 by using the mask 14. Finally, a contact hole 15' which is self-aligned with gate electrodes 4 and 4a is formed on a diffusion layer 8 by performing entire- surface etching back after depositing a second insulating film 16 and forming second side wall layers 17 on the side walls of the electrodes 4 and 4a. |
