IEEE Transactions on Semiconductor Manufacturing · 2013 · 18 citations · 3 references
Natural SciencesMaterials EngineeringMaterials ScienceMaterials ProcessingSurface ChemistrySurface ScienceChemical CleaningMechanical CleaningSurface CleaningSurface FinishesSurface OxidationSurface TreatmentClean TechniqueHybrid Process DesignHybrid Process SystemsHybrid Treatment ProcessesMetal Finishing ProcessesMetal Surface PreparationSurface Defect RemovalSurface Oxide Formation
A “hybrid” post Cu CMP cleaning process that combines acidic and basic clean in sequence is developed and implemented. The new process demonstrates the strengths of both acidic and basic cleans and achieves a more than 60% reduction in CMP defects, such as polish residues, foreign materials, slurry abrasives, scratches, and hollow metal, relative to an all-basic clean process. It also eliminates the circular ring defects that occur intermittently during roller brush cleans. TXRF scans confirm the reduction of AlO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> defects when using the hybrid clean process. XPS spectra show similar Cu surface oxidation states between the basic and hybrid clean processes. As revealed by XRD analysis, surface Cu oxide is dissolved into aqueous solution by the acidic clean chemical. The formation mechanism of circular ring defects and the key to their elimination is discussed.
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