| 摘要 |
PROBLEM TO BE SOLVED: To form a contact hole in a self-aligned manner to a bit line. SOLUTION: Grooves 2 are cut in a silicon oxide film 1, a barrier metal 3 and a tungsten film 4 are deposited, the surface of the silicon oxide film 1 is flattened by grinding, and a wiring layer formed of the tungsten film 4 is provided. The tungsten film 4 and the barrier metal 3 are etched for the formation of U-shaped grooves 5, a silicon nitride film 6 is deposited to fill in the U-shaped grooves 5 respectively, the silicon nitride films 6 are flattened by grinding. The silicon oxide film 1 is etched using a prescribed pattern as a mask, whereby a contact hole 8 is formed in a self-aligned manner. A silicon nitride film 6 is deposited and etched back for forming a side wall 9 on the inner wall of the contact hole 8, and then a barrier metal 10 and a tungsten film 11 are successively deposited to fill in the contact hole 8 and then ground down to be flattened until the silicon oxide film 1 and the silicon nitride film 6 are exposed. |
