APPLICATIONS OF APCVD TEOS O3 THIN-FILMS IN ULSI IC FABRICATION/

Void-free dielectrics are required for advanced IC development to enab le chemical-mechanical polishing and trench isolation, both of which a re essential for deep submicrometer processing. Atmospheric-pressure C VD (APCVD) using tetraethylorthosilicate/ozone (TEOS/O3) chemistry is a proven technology for depositing void-free oxides. This paper presen ts basic film and process characteristics, as well as electrical test results for TEOS/03 oxides used for intermetal, premetal, and shallow trench isolation in small geometries. An APCVD-ozone process for boron - and phosphorus-doped TEOS films produces films that planarize at low temperatures and meet the requirements of deep submicrometer salicide technologies. The deposition process produces a conformal, uniform, a nd stable oxide with dopant concentrations as high as 27 mol% and surf ace angles less than 30-degrees after furnace annealing as low as 800- degrees-C. The intermetal dielectric gap-fill process produces fully f unctional 0.5-mum CMOS logic and BiCMOS memory test circuits. The adva ntages of a thin plasma-enhanced CVD TEOS barrier between TEOS/03 and the underlying metal are explored. Undoped APCVD TEOS/03 films for iso lation trench fill are characterized and the relevant process variable s evaluated. Well-behaved transistors with excellent parasitic perform ance were achieved using trench isolation at geometries down to 0.5 mu m.