| 摘要 |
A method for forming an isolation region in a semiconductor substrate is disclosed. The present invention includes forming an insulating layer on the semiconductor substrate, and then forming a dielectric layer on the insulating layer. After patterning to etch portions of the dielectric layer, the insulating layer and the semiconductor substrate are etched using the patterned dielectric layer as a mask, thereby forming a trench in the semiconductor substrate. Next, a first silicon oxide layer is formed over the semiconductor substrate, and the first silicon oxide layer is then anisotropically etched to form a spacer on the sidewalls of the trench. Thereafter, the semiconductor substrate is thermally oxidized to form a field oxide region over the semiconductor substrate, and a second silicon oxide layer is then formed over the field oxide region. Finally, the second silicon oxide layer is etched back until surface of the dielectric layer is exposed.
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