TRENCH HAVING THICK DIELECTRIC SELECTIVELY ON BOTTOM PORTION

摘要

A method of fabricating a semiconductor device includes etching a semiconductor substrate having a top surface to form a trench having sidewalls and a bottom surface that extends from the top surface into the semiconductor substrate. A dielectric liner of a first dielectric material is formed on the bottom surface and sidewalls of the trench to line the trench. A second dielectric layer of a second dielectric material is deposited to at least partially fill the trench. The second dielectric layer is partially etched to selectively remove the second dielectric layer from an upper portion of the trench while preserving the second dielectric layer on a lower portion of the trench. The trench is filled with a fill material which provides an electrical conductivity that is at least that of a semiconductor.

主权项

1. A method of fabricating a semiconductor device, comprising:
etching a semiconductor substrate having a top surface to form a trench having sidewalls and a bottom surface that extends from said top surface into said semiconductor substrate; forming a dielectric liner comprising a first dielectric material on said bottom surface and said sidewalls of said trench to line said trench; depositing a second dielectric layer comprising a second dielectric material to at least partially fill said trench; partially etching said second dielectric layer to selectively remove said second dielectric layer from an upper portion of said trench while preserving said second dielectric layer on a lower portion of said trench and while preserving the dielectric liner in the upper portion of the trench and the lower portion of the trench, and filling said trench with a fill material which provides an electrical conductivity that is at least that of a semiconductor, wherein the dielectric liner lines the fill material in the trench.