Texas Instruments Corporation

Thomas R Seha

Kelly Jay Taylor

Keith Alan Joyner

Byron T Ahlburn

Rajan Rajgopal

After formation of a sandwich over a substrate of a layer of silicon dioxide (3) followed by a layer of silicon (1) having a pad oxide (7) thereon and a patterned silicon nitride layer (9) over the pad oxide, the unmasked portion of the pad oxide and silicon are removed to provide mesas of silicon with silicon nitride thereover and possibly removal of some of the buried oxide layer. A flowable insulator (15), preferably silsesquioxane (H.sub.x SiO.sub.1.5, where x.ltoreq.1, depending upon the level of polymerization) in a contaminant-free, high purity solvent which is later removed during an annealing step, is placed over the exposed surface such that it fills the voids between the mesas of silicon with silicon nitride thereon and extends over the nitride. The flowable insulator, due to its flowability, provides a generally planar surface. The flowable insulator is etched back and a cap oxide (17) is optionally deposited over the etched back insulator layer. The cap oxide layer (if used), some insulator and nitride are then etched away, leaving the pad oxide over the silicon. The processing is then completed by removing the pad oxide, growing a gate oxide and then forming the gate and source drain electrodes and/or other processing techniques that may be required to provide the final device.

Mesa isolation Refill Process for Silicon on Insulator Technology Using

A method of forming a planar dielectric layer over an interconnect pattern which requires fewer processing steps and has a lower dielectric constant than is obtained in the prior art. The method comprises providing a substrate having an electrical interconnect pattern thereon, forming a first layer of dielectric over the interconnect pattern, preferably by plasma generated TEOS oxide, forming a porous second layer of silicon-containing dielectric with low dielectric constant different from the first layer over the first dielectric layer from an inorganic silicon-containing composition, preferably hydrogen silsesquioxane and forming a third layer of dielectric different from the second layer over the second dielectric layer, preferably by a plasma generated TEOS oxide. The step of forming the second layer comprises the steps of depositing an inorganic silicon-containing composition capable of being pyrolytically converted to a silicon oxide over the first layer and placing the resulting structure in an essentially pure nitrogen and essentially moisture-free environment at a pressure at or below atmospheric pressure and then heating the silicon-containing composition to a temperature of from about 375.degree. C. to about 425.degree. C. and preferably 400.degree. C. for from about 30 minutes to about 90 minutes to convert the silicon-containing composition to silicon oxide.

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Dallas, TX, United States of America

Thomas R Seha