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Organic additives based alkaline alumina slurry for selective removal of barrier layer metals

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Title Organic additives based alkaline alumina slurry for selective removal of barrier layer metals
 
Creator Shukla, Arpita
Selvam, Noyel Victoria
Ramachandran, Manivannan
 
Subject Alkaline alumina slurry
Barrier layer
Chemical mechanical planarization
Material removal mechanism
Organic additives
Selectivity
 
Description 261-269
In the present work, tantalum (Ta) and copper (Cu) chemical mechanical polishing (CMP) has been carried out using a
polishing slurry containing 2 wt% alumina (abrasive), 1 wt% potassium carbonate (oxidizer), and 0.25 wt% each urea and
citric acid (additives). The Cu removal rate (RR) decreases with an increase in pH and is found to be minimum at pH 11
while Ta RR increases till neutral pH and then decreases till pH 11 having maximum RR at pH 7. Ta to Cu removal rate
selectivity of 1:1.02 is attained at pH 11. Other parameters such as the effect of additives concentration, applied pressure,
and platen rotational speed are also studied and results are reported to get a clear scenario. Surface charge analysis reveals
that with change in pH, zeta potential alters and 30mV zeta potential is found at pH 11 which confirms the stability of the
formulated slurry. To comprehend the removal mechanism of the metals, potentiodynamic polarization and electrochemical
impedance spectroscopy (EIS) are employed. The same trend is encountered for both corrosion current density (Icorr) and
film resistance (Rfilm)values resulting from Tafel and EIS. Based on the research conducted a plausible material removal
mechanism is suggested.
 
Date 2022-06-27T09:32:13Z
2022-06-27T09:32:13Z
2022-05
 
Type Article
 
Identifier 0975-0991 (Online); 0971-457X (Print)
http://nopr.niscpr.res.in/handle/123456789/59936
 
Language en
 
Publisher NIScPR-CSIR, India
 
Source IJCT Vol.29(3) [May 2022]