High-Z metal-based underlayer to improve EUV stochastics (Conference Presentation)

Extending extreme ultraviolet (EUV) single exposure patterning to its limits is dependent on eliminating its stochastic defectivity. Along with developments in photoresist platforms, the patterning film stack also needs to be considered. The material immediately underneath the photoresist is expected to have significant impact on both lithographic and pattern transfer performance. By designing the resist substrate interface with high EUV absorbance, there is potential to increase the EUV quantum yield of the exposure process. This paper will demonstrate the patterning of a chemically amplified resist on a high-Z metal-based hardmask. The potential for dose reduction, higher etch selectivity, and defectivity improvement from a high-Z hardmask will be discussed. Deposition-trim etch techniques will be used for decreasing the transfer of stochastic defects to the underlying substrate. Sub-32nm pitch trench patterning, defectivity, and electrical yield for this patterning stack will be highlighted.