Method for minimizing the vapor deposition of tungsten oxide during the selective side wall oxidation of tungsten-silicon gates
AssigneeInfineon Technologies AG
InventorsOlaf Storbeck, Wilhelm Kegel, Jens-Uwe Sachse, Michael Stadtmüller, Regina Hayn, Erwin Schoer, Georg Roters, Steffen Frigge
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Abstract
During a selective oxidation of gate structures that includes a polycrystalline silicon layer and a tungsten layer, which is known per se, a vapor deposition of tungsten oxide is prevented or at least greatly reduced by a special process. The gate structure is acted on by a hydrogen-containing, nonaqueous inert gas before and, if appropriate, after a treatment step with a hydrogen/water mixture.
Claims21
A method for selectively oxidizing a metallization structure having at least one silicon layer to be oxidized and at least one tungsten layer which is not to be oxidized, which comprises the steps of:
- performing a treatment step which includes subjecting the metallization structure to a mixture of hydrogen and water and supplying heat;
- and
- subjecting the metallization structure to a nonagueous hydrogen-containing substance, before and after the treatment step.
A method for selectively oxidizing a metallization structure having at least one silicon layer to be oxidized and at least one tungsten layer which is not to be oxidized, which comprises the steps of:
- performing a hydrogen/water treatment step which includes subjecting the metallization structure to a mixture of hydrogen and water throughout the whole hydrogen/water treatment step and supplying heat;
- subjecting the metallization structure to a nonaqueous hydrogen-containing substance, before and, optionally, after the hydrogen/water treatment step;
- and
- during the hydrogen/water treatment step, setting a supply of the heat such that a temperature of the metallization structure is increased from a defined temperature to a process temperature.
A method for selectively oxidiang a metallization structure having at least one silicon layer to be oxidized and at least one tungsten layer which is not to be oxidized, which comprises the steps of:
- performing a hydrogen/water treatment step which includes subjecting the metallization structure to a mixture of hydrogen and water throughout the whole hydrogen/water treatment step and supplying heat;
- and
- subjecting the metallization structure to a nonaqueous hydrogen-containing substance, immediately before and, optionally, after the hydrogen/water treatment step.
Dependencies are inferred from the claim text.