Method for forming semiconductor field region dielectrics having globally planarized upper surfaces

Abstract

Abstract An isolation technique is provided for improving the overall planarity of trench isolation regions relative to adjacent silicon mesas. The isolation process results in a spaced plurality of field dielectric having an upper surface substantially coplanar with each other and with adjacent silicon mesa upper surfaces. The isolation process is thereby a planarization process used with the shallow trench technique, wherein etch-enhancing ions are forwarded into the fill dielectric at upper elevational regions of that dielectric. When subjected to a subsequent etchant, the dopants cause the higher elevational regions to be removed at a faster rate than the lower elevational regions. Thus, selective placement of dopants and etch removal pre-conditions the fill dielectric upper surface to a more planar surface globally across the entire wafer. After etch removal predominantly at the higher elevational regions, the remaining fill dielectric upper surface is removed to a level commensurate with the upper surface of silicon mesas thereby producing separate field dielectrics interposed between silicon mesas. The field dielectrics, regardless of their lateral area, each have a substantially planar upper surface at or slightly below the adjoining silicon mesas. By producing planar field dielectric upper surfaces, various problems of non-planarity are removed from the thin films which are thereafter formed on the field dielectrics or between the field dielectrics and silicon mesas.

Inventors

• 👤 William S. Brennan
• 👤 Robert Dawson
• 👤 Fred N. Hause
• 👤 Basab Bandyopadhyay
• 👤 H. Jim Fulford, Jr.
• 👤 Mark W. Michael

Bibliographic Details