2545
Synthetic Design of a Supramolecular Complexing Agent for Advanced Cu Chemical Mechanical Planarization Applications

Tuesday, 15 May 2018
Ballroom 6ABC (Washington State Convention Center)
N. Mistry, M. Hill, L. Kilmer, H. Shuchi, D. S. Kissel, and J. J. Keleher (Lewis University, Department of Chemistry)
As the complexity of three-dimensional large-scale integration (3D-LSI) circuits increases, copper (Cu) Chemical Mechanical planarization (CMP) has emerged as a critical step in the fabrication of semiconductor wafers attaining global planarization. Through-silicon Via (TSV) CMP incorporates elimination of deposited excess trench overburden above a silicon wafer at a high removal rate, thus allowing additional layers to be added for substantial 3D-LSI circuit architecture. Enhancing the planarity of the substrate as a result of undesired topography removal is controlled through optimization of slurry composition. In traditional slurries, a synergistic chemical interaction between a corrosion inhibitor and a complexing agent removes irregularities from the surface while at high downforce. To optimize slurry interaction and promote film formation at the interface, a suite of additives incorporating both properties of the slurry are being developed. More specifically, the functionalization of a supramolecular structure enables removal rate to rely heavily on surface chemistry due to its polymeric nature while simultaneously preserving surface uniformity. The introduction of substituents with high-binding affinity for Cu into the slurry such as heterocyclic pyridines, amino, and carboxyl groups directly correlate to a higher removal rate. Preliminary results have shown a correlation between the molecular structure of the complexing and inhibiting agents and their effect on film formation. Adding a system that integrates simultaneous chelation and passivation to the slurry via the supramolecular complex will directly impact the planarity and therefore alter the removal mechanism. This work employs electrochemical surface analysis such as open-circuit potential (OCP) to monitor film formation kinetics and results have shown a direct correlation to CMP parameters.