Seedless copper electroplating on Ta from an alkaline activated bath

David Starosvetsky, Nina Sezin, Yair Ein-Eli

Research output: Contribution to journalArticlepeer-review


The miniaturization of ULSI design below 32 nm requires new strategy to copper interconnect metallization. Metallization techniques forming Cu seed layer on Ta barrier film prior to feature filling by Cu electroplating cannot be effective once feature dimensions are comparable with seed layer thickness. Thus, copper electroplating has to be performed directly over a Ta barrier film (seedless deposition), while Ta thickness itself must also be significantly reduced. Copper electroplating on Ta surface from a two components injected bath is being further described in this work. Copper electrodeposition over a thin TaN/Ta barrier was performed in a two steps process; (1) Activation conducted by electrochemically reduction of Ta oxide from the TaN/Ta barrier at a negative potential of -2 V for a short period ("removal" step) and (2) copper electroplating performed in the invariable electrochemical bath by injecting a solution containing Cu-ions. Supplementary Cu plating is continued by shifting the applied potential to -1.2 V in the same electrolytic bath. It was also established that addition of low content (up to 10 ppm) dimercaptothiadiazole (DMcT) assists Cu nucleation and growth on Ta surface and allows a conformal features fillings. Copper layer deposited is characterized with an excellent adhesion to the Ta surface.

Original languageEnglish
Pages (from-to)367-371
Number of pages5
JournalElectrochimica Acta
StatePublished - 1 Nov 2012


  • Electroplating
  • Oxide removal
  • Seedless copper
  • Single bath
  • Ta barrier

All Science Journal Classification (ASJC) codes

  • General Chemical Engineering
  • Electrochemistry


Dive into the research topics of 'Seedless copper electroplating on Ta from an alkaline activated bath'. Together they form a unique fingerprint.

Cite this