Abstract
As the design rule of logic semiconductors has been scaled down to 5, 3, 2.1, 1.5, and 1.0 nm, the line width of Cu film used as interconnect lines in logic semiconductors has also been rapidly reduced to 36, 32, 24, 20, and 16 nm. The CMP (Chemical Mechanical Planarization) of these Cu lines is a crucial fabrication process, posing challenges in achieving E.O.E (Edge Over Erosion), as well as minimizing dishing and erosion during the CMP of Cu films. Specifically, the E.O.E in the CMP of Cu films is primarily influenced by the diameter and morphology of colloidal silica abrasives in the CMP slurry. In a conventional synthesis method synthesis of colloidal-silica-abrasives, the diameter of colloidal-silica-abrasives could be obtained by adjusting the precursor concentrations such as TEOS, alcohol, and alkali catalyst. It has been reported that the effect of precursor concentration and the presence of a carboxylic acid-functionalized surfactant, specifically ethylene-diamine-tetraacetic acid (EDTA), on the morphology of colloidal silica abrasives.Therefore, in our study, we designed a novel synthesis method for colloidal silica abrasives by incorporating a charged functional group surfactant into the conventional synthesis process of colloidal silica abrasives. The effect of the surfactant having the positive charged amine functional group (i.e. Triethanolamine: Tri-ETA, Ethylenediamine: EDA, Diethylenetriamine: DETA, Triethylenetetramine: TETA) were estimated as function of the number of amine functional group in the surfactant, as shown in Fig. 1. When the number of positive charged amine functional groups increased 0 to 4, the diameter of colloidal-silica-abrasives increased from 67.2 to 143.86 nm and the solid loading of colloidal-silica-abrasives increased from 2.0 to 2.2 wt%. In addition, the synthesis with positive charged amine functional group was transformed from cocoon shape to spherical shape. We will present the changes in colloidal silica abrasive morphology as the concentration of amine functional groups, as well as the distinctions between amine and carboxyl funtuonal group. Moreover, we intend to provide a thorough investigation into the mechanisms underlying each synthesis. Acknowledgement This research was supported by the MOTIE(Ministry of Trade, Industry & Energy (1415180388) and KSRC(Korea Semiconductor Research Consortium) (20019474) support program for the development of the future semiconductor device, and by the Brain Korea 21 PLUS Program and the Samsung Electronics’ University R&D program. Figure 1
Published Version
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