| 摘要 |
PROBLEM TO BE SOLVED: To form a stabilized through hole while avoiding void and short circuit with a conductive layer when a lower contact plug is connected directly with an upper contact plug. SOLUTION: A silicon oxide film 1, a silicon nitride film 2, and a silicon oxide film 3 are formed sequentially, a through hole is made therein and filled with a conductive material to form a lower contact plug 6, and then the silicon oxide film 3 is removed. A silicon nitride film 7 is then formed on the entire surface and etched back to form a side wall 8 around the lower contact plug 6. Thereafter, upper part of the side wall 8 is planarized, a silicon oxide film 12 is formed on the entire surface, and a through hole is made through the silicon oxide film 12 and filled with a conductive material to form an upper contact plug 15 in connection with the lower contact plug 6. |
