Stuardo Robles

Surface Related Phenomena in Integrated PECVD/Ozone‐TEOS SACVD Processes for Sub‐Half Micron Gap Fill: Electrostatic Effects

Surface related phenomena of subatmospheric chemical vapor deposition (SACVD) films were systematically studied on different types of plasma enhanced CVD (PECVD) oxides. The PECVD oxides are part of a new and in situ2 step gap fill process consisting of a thin PECVD underlayer and a thick SACVD oxide being proposed for advanced ULSI devices. Differences in deposition rates, wet etch rate, surface morphology, and stress‐temperature behavior of SACVD films deposited on PECVD oxide underlayers and bare silicon substrates were evaluated. For the PECVD underlayers which render surface dependence for the SACVD film, various plasma treatments of the underlayer was used to eliminate the effect. An extensive analysis of the surface and bulk properties of these PECVD oxide underlayers suggests that the occurrence of the surface dependence effects can be attributed to the presence of electronegative species such as fluorine on the surface of the PECVD oxide underlayer.

Moisture Resistance of Plasma Enhanced Chemical Vapor Deposited Oxides Used for Ultralarge Scale Integrated Device Applications

The moisture resistance of plasma enhanced chemical vapor deposited (PECVD) oxide films used in ultralarge scale integrated (ULSI) device applications has been characterized using infrared (IR) spectroscopy. The differences in the moisture absorption characteristics between tetraethylorthosilicate (TEOS) and silane-based PECVD oxides are presented. Our results indicate that the film thickness and the as-deposited film stress are important factors in controlling the moisture resistance of these PECVD oxides; the deposition of these PECVD oxides using higher O 2 :TEOS ratios enhances moisture resistance; the use of N 2 O instead of O 2 as the oxidizing agent incorporates nitrogen as well as Si-H bonds in the film which enhance moisture resistance, and that an in situ N 2 plasma post-treatment of PECVD TEOS-O 2 films improves the moisture barrier characteristics of the these oxide films

Gap Fill and Film Reflow Capability of Subatmospheric Chemical Vapor Deposited Borophosphosilicate Glass

This work presents a systematic process characterization of subatmospheric chemical vapor deposited (SACVD) borophosphosilicate glass (BPSG). The effects of deposition pressure, ozone concentration, ozone flow, and dopant concentration on the film reflow profile and film properties are presented. Our results indicate that a decrease in the deposition pressure from atmospheric conditions to 200 Torr provides more than a 200% increase in SACVD BPSG deposition rate without affecting film quality. Phosphorous is incorporated in the stable form of P 2 O 5 at all deposition pressures. Higher ozone concentrations improve SACVD BPSG film reflow and film properties. Moreover, at higher dopant concentrations, both film shrinkage and stress-temperature hysteresis decrease.

Stress-Temperature Behavior of O 3 -TEOS Sub-Atmospheric CVD (SACVD) Oxide Films Deposited on Various Oxide Underlayers

A systematic evaluation of the stress-temperature behavior of O 3 -TEOS Sub-Atmospheric CVD (SACVD) oxide films used in IMD applications was performed in order to elucidate the surface dependence and mechanical stability of these films when deposited on different oxide underlayers such as PECVD TEOS-based, Silane-based, and thermally grown oxides. SACVD films were deposited at 360°C using different O 3 :TEOS molar flow ratios. The results obtained in this study indicate that the stress-temperature behavior of SACVD films deposited on PECVD Silane-based and TEOS-based oxides using N 2 O as the oxidizing agent is similar to that of the SACVD films deposited on silicon. However, a large stress hysteresis is obtained when SACVD films are deposited on PECVD TEOS-O 2 and thermally grown oxide underlayers. This large stress hysteresis results from the surface dependence effects of the SACVD oxides on thermally grown and PECVD TEOS-O 2 oxide underlayers. Also, this stress hysteresis can be reduced or eliminated by treating the oxide underlayer surface with an in-situ Ar, He, or N 2 plasma. Furthermore, it was also found that the SACVD oxides deposited using higher O 3 :TEOS molar flow ratios are chemically and mechanically more stable.