| 摘要 |
PURPOSE: To produce no recess on the silicon nitride film liner of a trench shoulder part even when the film thickness of the silicon nitride film liner is made thickness functioning as the liner. CONSTITUTION: A silicon oxide film spacer 27 is formed on the opening part side wall of the silicon nitride film 24, the silicon nitride film 24 and the silicon oxide film spacer 27 are etched and masked, and a trench 28 is formed on a silicon board 21. The silicon nitride film liner 32 is formed in the trench 28 on the silicon board 21 removing the silicon nitride film 24 and the silicon oxide film spacer 27. After the silicon oxide film is filled into the trench 28, the silicon nitride film liner 32 of the side wall of the silicon nitride film 24 is also simultaneously removed when the silicon nitride film 24 is removed by hot phosphoric acid, it is not easily immersed to the shoulder part of the trench and the recess can be prevented because the silicon nitride film liner 32 sandwiched by the silicon board 21 and the silicon oxide film with the shoulder part of the trench.
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