| 摘要 |
In a process for manufacturing an integrated circuit structure an oxide layer (11) is provided on a silicon substrate, a silicon nitride layer (12) is provided on the oxide layer and a photoresist mask (14) is then patterned and utilized to etch the nitride layer (12) such that the mask (14) has an edge projecting beyond the nitride layer (12). The substrate is then subjected to ion implantation, regions underlying the mask (14) being protected from implantation. The implanted ions are then diffused a predetermined distance beneath the mask (14). Next, oxidation at a temperature of 700-800<o>C is effected, the differential oxidation rate of doped and undoped silicon reducing the formation of undesired "bird's head" and "bird's beak" features in the resulting oxide (18). To form a true coplanar structure, the formed oxide (18) is removed, a further ion implantation is effected using the nitride (12) as a mask and a further oxidation step is effected. Alternatively an unoxidized doped region resulting from the initial ion implantation may be utilized during the second oxidation step. |
