E-beam lithography using dry powder resist of hydrogen silsesquioxane having long shelf life

Hydrogen silsesquioxane (HSQ) is arguably the most popular negative e-beam resist for academic research. One of the most significant advantages of HSQ is its ultrahigh resolution. However, it has a short shelf life, which increases its cost. As an alternative, a new type of dry powder HSQ resist resin (Applied Quantum Materials, referred to as AQM) was introduced here, the shelf life of which can be considered as infinitely long. A small amount of the powder can be dissolved in a solvent as needed right before exposure. Furthermore, this powder HSQ resist has a similar resolution and sensitivity parameters. By using the high-contrast development process with a salty developer, a 7.5 nm half-pitch nested “L” shape structure is achieved.