The CMP effect of Potassium Molybdate with BTA as Compound Corrosion Inhibitor used in CMP of the TSV Heterogeneous Microstructure

Through Silicon Via (TSV) Technology is the core technology of three-dimensional integration, which is widely used in the integrated industry, and Chemical Mechanical Planarization (CMP) is an essential process in the TSV manufacturing. To improve the traditional 1st BVR process, which is wet etching, CMP process is attempted to be used. In this paper, experiments were performed to study the effect of the compound inhibitor composite of benzotriazole (BTA) and potassium molybdate (K
₂
MoO
₄
), and to figure out the effect of K
₂
MoO
₄
in the alkaline slurry during CMP of the TSV backside heterogeneous microstructure. CMP experiments were conducted to figure out the TSV wafers' backside topography. Atomic Force Microscope (AFM) measurements were used to evaluate the polished surface topography, and AFM scratch experiments were done to evaluate the removal mechanism of Cu. Cross-sectional TEM measurements were conducted to figure out the subsurface damage. The results illustrate that the addition of K
₂
MoO
₄
can improve the mechanical removal of Cu chemical surface layer and reach the saturation point at around 15 mM, K
₂
MoO
₄
can enhance the inhibition effect of BTA on the corrosion of the interface of Cu and the barrier layer.