Fluorine Saturated Yttrium (YF) Based Coatings for Advanced Semiconductor ULSI Manufacturing

Fluorine saturated Yttrium based coatings have been developed to generate highly stable electrical, mechanical and chemical interfaces that minimize defect generation in reactive plasma environments utilized in the manufacturing process of advanced ULSI microchips. In this study, single-layer YF3 (YF) coatings are compared to the current dual-layer coatings DLC (Y2O3/YF3) option. The performance of the YF interface compared to that of dual-layer DLC is discussed. The results show that the electrical, mechanical and chemical properties of YF based functional coating are not detrimentally affected when exposed to harsh halide enriched environments and thereby are suitable to be applied as protective layers on anodized surfaces to prevent extreme surface degradation due to Fluorine/Oxygen radical interactions. The achieved thermodynamic stability on YF based films is attributed to the higher enthalpy of dissociation of the Y-F bond compared to that of Y-O at the base of the dual-layer coating. Likewise, due to Fluorine electronegativity, it is shown that YF films undergo less interface volume expansion due to O replacement as traditionally observed in the Y2O3 base of the DLC coating. It is understood that volume expansion leads to interface cracks and weak points that generate particle defects. Ultimately, these YF films can be reliably employed on anodized etch reactor surfaces to improve defect as well as process limited yield (PLY) baselines on advanced ULSI technology nodes. Our work is focused on early evaluation and adoption of YF coatings to improve the development and manufacturing of advanced ULSI circuits.