LWR Improvement in the Advanced Process Node Involved in 193nm Photoresist Treatment

The line width roughness (LWR) in the advanced process node is one of the most critical parameters in obtaining high yield of devices. Ar and HBr plasma treatments are widely used in curing ArF photoresist (also known as 193nm PR) before etch. The VUV light irradiation emitted by Ar / HBr plasma is known as a major role by rearranging the polymer chains and changing carbon speciation at surface to improve LWR. In this study, the effects of curing time, temperature and sequence of Ar cure and HBr cure on LWR were explored. The "sweet point" of LWR was found with increasing the curing temperature under appropriate curing time. Finally, the optimized curing process, which was applied to the fabrication of product wafer of line patterns, was demonstrated that LWR was improved.