No abstract

With the rapid miniaturization of advanced technologies, limiting device defects has become of utmost importance in maintaining high performing integrated circuits. Shallow trench isolation (STI) chemical mechanical planarization (CMP) uses a synergistic balance of ceria (CeO2) nanoparticles and functional chemistry to modulate surface adsorption interactions necessary to remove excess topography. This work aims to develop a post-CMP cleaning chemistry that enhances nanoparticle removal via “soft” encapsulation by employing a polyelectrolyte/surfactant (PES) matrix. A surface adsorbing/charge flipping encapsulation process is proposed as a vehicle to remove slurry contamination at low friction. Investigation into the synergy between slurry chemistry and PES cleaning chemistry, with respect to defect aggregate formation, was correlated to the cleaning efficiency as well as friction. Using a suite of techniques to study the real-time defect aggregate formation mechanism it was determined that the supramolecular structure is critical to balance defect forming events with enhanced cleaning efficiency.

Supramolecular nanocomposite materials have emerged as a leading interdisciplinary research area that exploits synergistic relationships at the nanoscale to enhance the properties (mechanical and chemical) of nextgeneration biopolymeric materials. Hydrogels synthesized from natural biopolymers have emerged because of their intrinsic properties such as noncytotoxicity and biodegradability as well as their well-defined threedimensional, noncovalent network that is ideal for modification and functionalization. Therefore, it is critical to develop a mechanistic understanding tailored to the nuances involved in the interactions of the biopolymer scaffold with the functional additives present in these complex matrixes. This work will discuss the strategic design of hydrogels placing emphasis on the selection of the biopolymer network and the critical role that the incorporation of additives such as biomimetic cross-linking agents (lactones/amino acids) and antimicrobial nanoparticles (NPs) has on the properties and responsiveness of the final nanocomposite. Results have shown that the hydrogen bonding capacity of the biomimetic additives and antimicrobial agents (i.e., AgNPs) impacts the packing density of the hydrogel network and therefore modulates the resultant swellability. Furthermore, the addition of Ag-coated TiO 2 NPs (Ag/TiO 2 NPs) and biomimetic additives provided antimicrobial activity along with enhanced closure rates of simulated wounds in adult human dermal fibroblasts.

Due to the emergence of sub-10 nm technologies, next generation slurries have continued to increase in complexity to meet stringent device performance demands. Prior to the chemical mechanical planarization (CMP) process, point-of-use filtration (POU) is implemented in order to limit particle aggregates and ultimately decrease surface defects. This study probes the non-covalent interactions at the interface of a fundamental Cu slurry and a polyamide and polypropylene-based membranes. Results indicate that independent of the membrane used, material removal rate (MRR) showed a subtle decrease as a result of filtration (time and ΔP), demonstrating that the synergistic balance between the nanoparticle and slurry additives is disrupted during the filtration process. Corrosion current measurements (Icorr) decreased by at least 85% post-filtration, indicating a rapid adsorption of glycine to the filter membrane. Regardless of the filter membrane, glycine adsorption was further validated using a modified electrochemical quartz crystal nanobalance (EQCN) technique. Since Cu-glycine complexes are integral in controlling MRR, a widely reported method of tracking *OH production was employed. Results show a decrease in the concentration of *OH, which in turn can be correlated to a decrease in the Cu-glycine complexes, altering the overall Cu MRR.

We have shown how different micellar (SDBS) vs. polyelectrolytic (PSSA) supramolecular assemblies in post-CMP cleaning solutions differ in their tribological performance when used in a novel PVA scrubber for 300-mm silicon dioxide wafer cleaning. Significant differences in real-time shear force and coefficient of friction data from the wafer-solution-brush interface (both in time domain as well as frequency domain) have been attributed to differences in each supramolecule’s chemical functionality and structure, which in turn, have been correlated to wafer-level defects. The work has underscored the importance of measuring the tribological attributes of post-CMP cleaning processes in an effort to improve cleaning performance.