High-carbon fullerene based spin-on organic hardmask

Irresistible Materials has previously introduced the HM340 series of fullerene based spin-on carbon, and reported on material characterization, including very high carbon content and high thermal stability. The materials have a low Ohnishi number providing high etch durability and the low hydrogen level allows for high-resolution etching without wiggling. Here we present further investigation of the spin-on-carbon, and demonstrate the flexibility of the platform. Film carbon content can be easily varied from as high as 95% (suitable for high durability etches) to as low as 80% (for instance to use as a sacrificial etch material). We present characterisation of the optical properties of the materials, and process and formulation developments. Work to vary the curing temperature between 200 and 300°C, and to reduce cure times to 90 seconds or less has been successfully undertaken. Alternative casting solvents have been investigated and work to achieve spin coatable film thickness ranges from less than 50 nm to significantly more than 500nm is described. and spin-coatable film thickness ranges from less than 50 nm to significantly more than 500nm are described. Results from initial planarisation trials are presented together with initial results from on-going work on spin-on carbon formulations that exceed 95% carbon content.