Design and synthesis of materials for 157 nm photoresists applications

The move towards 157 nm as the next generation of photolithography has presented many challenges. One of the more challenging aspects of 157 nm photolithography is the development of a suitable photoresist. Two of the issues faced when designing a suitable resist for 157 nm applications are transparency requirements and outgassing from the photoresist. Designing a resist to not intentionally outgass upon exposure to acid and heat employed the screening of several new potential solubility switches. Several lactones were synthesized and NMR was used as a spectroscopic method to monitor whether the desired solubility switch occurred in model compounds. Successful model compounds were incorporated into polymers to form a photoresist. Subsequent imaging experiments gave insight into the desired copolymer ratios needed for imaging applications. The formation of base insoluble lactones from base soluble precursors were also investigated for use as a non-outgassing negative tone photoresist. Successful model compounds were incorporated into copolymers. Imaging experiments gave insight on the terpolymer ratios needed for to obtain imaging. Transparency of the polymer resin has been a major hurdle in the development of a 157 nm photoresist. Efforts to use top surface imaging (TSI), an alternative lithographic patterning technique have been explored. TSI, unlike traditional photolithographic schemes, does not require a transparent resin. However, line edge roughness (LER) has always hampered the feasibility of TSI. Efforts to reduce the LER of TSI through manipulation of the Tg of the polymer resin were investigated.Chemistr