Semiconductor integrated circuit substrate containing isolation structures
AssigneeAdvanced Analogic Technologies, Inc.
InventorRichard K. Williams
Life of this patent
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Abstract
Isolation regions for semiconductor substrates include dielectric-filled trenches and field oxide regions. Protective caps of dielectric materials dissimilar from the dielectric materials in the main portions of the trenches and field oxide regions may be used to protect the structures from erosion during later process steps. The top surfaces of the isolation structures are coplanar with the surface of the substrate. Field doping regions may be formed beneath the field oxide regions. To meet the demands of different devices, the isolation structures may have varying widths and depths.
Claims8
A semiconductor substrate comprising:
- a first isolation structure comprising a first trench formed in the semiconductor substrate, the first trench being filled with a first dielectric material, a top surface of the first dielectric material being substantially coplanar with a surface of the substrate;
- and
- a second isolation structure comprising a second trench formed in the semiconductor substrate, the second trench being filled with a second dielectric material, a top surface of the second dielectric material being substantially coplanar with the surface of the substrate,
- wherein the first trench is deeper than the second trench and the second trench is wider than the first trench.
A semiconductor substrate comprising:
- a first isolation structure comprising a trench formed in the semiconductor substrate, the trench being filled with a first dielectric material, a top surface of the first dielectric material being substantially coplanar with a surface of the substrate;
- and
- a second isolation structure comprising a field oxide region, a top surface of the field oxide region being substantially coplanar with the surface of the substrate,
- wherein the trench is deeper than the field oxide region and the field oxide region is wider than the trench.
A semiconductor substrate comprising:
- a first isolation structure comprising a trench, the trench comprising a first layer of a first dielectric material and a second layer of a second dielectric material, the second layer overlying and completely covering the first layer in the trench, a surface of the second layer being substantially coplanar with a surface of the substrate, wherein the second dielectric material is relatively more resistant to removal by normal semiconductor etch processes as compared with the first dielectric material;
- and
- a second isolation structure comprising a field oxide region, a surface of the field oxide region being recessed with respect to the surface of the substrate, and a third layer of a second dielectric material overlying and completely covering the field oxide region, a surface of the third layer being substantially coplanar with the surface of the substrate, wherein the second dielectric material is relatively more resistant to removal by normal semiconductor etch processes as compared with the field oxide region.
Dependencies are inferred from the claim text.