摘要 |
A shallow trench isolation (STI) structure has a top portion tapering in width from wide to narrow in a direction from a substrate surface, from a first width at a top of the first portion to a second width at a bottom of the first portion. The STI structure also includes a bottom portion below the top portion, which expands from the bottom of the top portion to a substantially widened lateral distance having a third width. The third width is, in general, substantially larger than the second width. The inventive STI structure can provide desired isolation characteristics with a significantly reduced aspect ratio, thus suitable for device isolations in advanced processing technology.
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