Organic ice resists for 3D electron-beam processing: Instrumentation and operation

• Published in: Microelectronic engineering 2018-05, Vol.192, p.38-43
• Main Authors: Tiddi, William, Elsukova, Anna, Beleggia, Marco, Han, Anpan
• Format: Article
• Language: English
• Subjects: 3D lithography; Control systems; Electron beam lithography; Gas injection; Ion beams; Liquid nitrogen; Multilayer resist; Negative tone resist; Offset printing; Organic chemistry; Organic ice resist; Scanning electron microscopy; Semiconductors; Substrates; Temperature control; Thin films
• ISSN: 0167-9317; 1873-5568
• DOI: 10.1016/j.mee.2018.01.021

Organic vapors condensed into thin layers of ice on the surface of a cold substrate are exposed with an electron beam to create resist patterns for lithography applications. The entire spin- and development-free lithography process requires a single custom instrument. We report the design, material choice, implementation and operation of this apparatus. It is based on a scanning electron microscope fitted with an electron beam control system that is normally used for electron beam lithography in a multi-user open-access laboratory. The microscope was also equipped with a gas injection system, a liquid nitrogen cooled cryostage, a temperature control system, and a load-lock. Three steps are required to initialize the apparatus for organic ice resist processing, and two steps are required to restore the apparatus for routine multi-user operations. Five steps are needed to create organic ice resist patterns. Finally, by stacking nanoscale patterns made in organic ice we created 3D structures using two complementary cyclic condense, expose and sublimate processes. [Display omitted] •Spin- and development-free lithography process using condensed organic molecules at low temperatures•In-depth instrument design, realization and process flow•Two approaches for 3D multilayer lithography by stacking condensed organic ice layers