Low-Temperature, Universal Synthetic Route for Mesoporous Metal Oxides by Exploiting Synergistic Effect of Thermal Activation and Plasma.

Mesoporous metal oxides exhibit excellent physicochemical properties and are widely used in various fields, including energy storage/conversion, catalysis, and sensors. Although several soft-template approaches are reported, high-temperature calcination for both metal oxide formation and template removal is necessary, which limits direct synthesis on a plastic substrate for flexible devices. Here, a universal synthetic approach that combines thermal activation and oxygen plasma to synthesize diverse mesoporous metal oxides (V2O5, V6O13, TiO2, Nb2O5, WO3, and MoO3) at low temperatures (150-200 °C), which can be applicable to a flexible polymeric substrate is introduced. As a demonstration, a flexible micro-supercapacitor is fabricated by directly synthesizing mesoporous V2O5 on an indium-tin oxide-coated colorless polyimide film. The energy storage performance is well maintained under severe bending conditions.

Role of Oxygen in Amorphous Carbon Hard Mask Plasma Etching.

In the current and next-generation Si-based semiconductor manufacturing processes, amorphous carbon layer (ACL) hard masks are garnering considerable attention for high-aspect-ratio (HAR) etching due to their outstanding physical properties. However, a current limitation is the lack of research on the etching characteristics of ACL hard masks under plasma etching conditions. Given the significant impact of hard mask etching on device quality and performance, a deeper understanding of the etching characteristics of ACL is necessary. This study aims to investigate the role of oxygen in the etching characteristics of an ACL hard mask in a complex gas mixture plasma etching process. Our results show that a small change of oxygen concentration (3.5-6.5%) can significantly alter the etch rate and profile of the ACL hard mask. Through our comprehensive plasma diagnostics and wafer-processing results, we have also proven a detailed mechanism for the role of the oxygen gas. This research provides a solution for achieving an outstanding etch profile in ACL hard masks with sub-micron scale and emphasizes the importance of controlling the oxygen concentration to optimize the plasma conditions for the desired etching characteristics.

Database Development of SiO2 Etching with Fluorocarbon Plasmas Diluted with Various Noble Gases of Ar, Kr, and Xe.

In the semiconductor industry, fluorocarbon (FC) plasma is widely used in SiO2 etching, with Ar typically employed in the dilution of the FC plasma due to its cost effectiveness and accessibility. While it has been reported that plasmas with other noble gases, namely Kr and Xe, have distinct physical properties such as electron density and temperature, their implementation into plasma etching has not been sufficiently studied. In this work, we conducted SiO2 etching with FC plasmas diluted with different noble gases, i.e., FC precursors of C4F8 and CH2F2 with Ar, Kr, or Xe, under various gas flow rates of each as well as plasma diagnostics for the process interpretation. We show that Ar, Kr, and Xe gas mixtures depend on the FC precursor flow rate and the pattern width in a significantly different manner and we elucidate these findings based on plasma diagnostic results. The results of this work are expected to offer a practical etching database for diverse applications including plasma process engineering and the development of plasma simulation in the semiconductor industry.