Method of manufacturing a semiconductor device whereby field oxide regions are formed in a surface of a silicon body through oxidation.

摘要

A method of manufacturing a semiconductor device whereby field oxide regions (17) are formed in a surface (1) of a silicon body (2) through oxidation, which body is provided with an oxidation mask (15) formed in a layered structure provided on the surface with a lower layer (4) of silicon oxide, an intermediate layer (5) of polycrystalline silicon and an upper layer (6) of a material comprising silicon nitride in that windows (8) are etched into the upper layer, in that the intermediate layer is etched away inside the windows and below an edge (10) of the windows, a cavity (11) being formed below said edge, upon which a material comprising silicon nitride is provided in the cavity. According to the invention, the material comprising silicon nitride is provided in the cavity while the surface of the silicon body situated inside the windows is still covered by a layer of silicon oxide, preferably with the lower layer of the layered structure. Field oxide regions can be provided in this way having the same dimensions as the photoresist mask (7) used for etching the window into the upper layer, while in addition gate oxide (22) free from defects can be provided on the active regions (21) of the silicon body situated between the field oxide regions.