In order to investigate the copper gap-filling during micro electroplating process with additive (N’N-diethylthiourea)

the electrochemical behaviors of electrolyte were studied by SEM

CVS and XRD

the electrode dynamics parameters were studied by the Tafei equation. The results show when N’N-diethylthiourea was used during micro electroplating copper process

activation polarization was generated; the activation energy was improved; metal ion discharge rate was lowered from 2.2214 mA/ cm2 to about 0.076 mA/ cm2; the overpotential was increased

thus the crystal nucleus molding speed on the electrode was accelerated; the crystal growth speed was decreased from 2.57μm /min to about 0.17μm /min

leveling ability was increased about 50%. Side effect was lowered effectively

which make the copper ions with good ability of micro-trenches or micro-contacts filling. Further more

some micro trenches in the silicon wafer

the width is 10μm and aspect ratio is 4:1

were filled by micro electroplating process with N’N-diethylthiourea

however the electroplating layer have no voids or seams.