| 摘要 |
This invention provides a method of cleaning integrated circuit wafers which effectively removes precipitates formed as a result of the tungsten etchback process. When tungsten is used to fill via holes in an inter-metal dielectric layer an adhesion layer of titanium nitride, TiN, is required to provide good adhesion. As a result of the tungsten etchback, wherein fluorine based etchants are used, precipitates of TiF3 can form which are extremely difficult to remove. Methods, such as in-situ bake after the tungsten etchback, are used to prevent the formation of the precipitates but do not remove them after they are formed. This invention teaches a method using a strong oxidizing agent, such as H2O2, to cause an oxidation-reduction reaction which converts the precipitates to a water soluble form. The water soluble form of the precipitates are then removed using a water rinse and spin dry process.
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