High-Si content BARC for dual-BARC systems such as trilayerpatterning

摘要

This work discusses the requirements and performance of Honeywell's middle layer material, UVAS, for tri-layerpatterning. UVAS is a high Si content polymer synthesized directly from Si containing starting monomer components.The monomers are selected to produce a film that meets the requirements as a middle layer for tri-layer patterning (TLP)and gives us a level of flexibility to adjust the properties of the film to meet the customer's specific photoresist andpatterning requirements. Results of simulations of the substrate reflectance versus numerical aperture, UVAS thickness,and under layer film are presented. ArF photoresist line profiles and process latitude versus UVAS bake at temperaturesas low as 150°C are presented and discussed. Immersion lithographic patterning of ArF photoresist line space and contacthole features will be presented. A sequence of SEM images detailing the plasma etch transfer of line space photoresistfeatures through the middle and under layer films comprising the TLP film stack will be presented. Excellent etchselectivity between the UVAS and the organic under layer film exists as no edge erosion or faceting is observed as aresult of the etch process. A detailed study of the impact of a PGMEA solvent photoresist rework process on thelithographic process window of a TLP film stack was performed with the results indicating that no degradation to theUVAS film occurs.