Role of metal sensitizers for sensitivity improvement in EUV chemically amplified resist

Abstract

The requirements for next generation resist materials in extreme ultraviolet (EUV) lithography are very challenging. Therefore, the development of new resist materials and processes has been expected to meet strict requirements. In order to increase the sensitivity of EUV resists without losing resolution and line width roughness (LWR), it is essential to design new resist concept, which can increase pattern formation efficiency. Recently, metal sensitizers containing metal elements of high EUV absorbance have gained growing attention due to significant sensitivity improvement. However, the role of metal sensitizers for sensitivity improvement has been still unclear because of the absence of the fundamental study of the metal sensitizer. Therefore, it is very important to clarify the role of metal sensitizer for sensitivity improvement. In this study, we investigated the effect of metal sensitizers in the resist materials on acid yields using the acid dye method. The introduction of metal sensitizer leads to higher acid generation efficiency per unit volume. In addition, the dissolution behavior and the patterning performances of the resists containing metal sensitizer were investigated using quartz crystal microbalance (QCM) and electron beam (EB) lithography system. These results indicate metal sensitizers are promising method for the improvement of resist performance.