Integrated in situ self-aligned double patterning process with fluorocarbon as spacer layer

Abstract

Self-aligned double patterning (SADP), or spacer lithography, is a widely used technique in the semiconductor industry for high-throughput nanoscale pattern definition and thus is of great significance for very-large-scale integration, large-area photonic device fabrications, and other applications. In a standard SADP flow, chemical vapor deposition or atomic layer deposition is used to deposit a conformal spacer layer, which is typically a dielectric material. The spacer composition and film quality will influence downstream critical dimension control. However, samples have to go through multiple processing environments, and fabrication complexity is thus increased. In this work, an in situ SADP process is proposed, with all the fabrication steps being integrated into a single process inside a commercially available plasma etching equipment. The spacer layer is a plasma-deposited fluorocarbon film, which has a uniform step coverage and a good etch selectivity to silicon. Various nanostructures have been fabricated to prove the capability of this technique. With its high integrity and technical convenience, this method can be promising to improve the throughput and efficiency of nanofabrication in the semiconductor industry, microelectromechanical systems, and photonic engineering.