Encapsulated inorganic resist technology

Resolution in traditional, single layer organic resists has been limited by the inability to image at aspect ratios (resist height to image width) of much greater than 3.1. Unless plasma etch selectivity increases several fold (an unlikely event with organic based resists) single layer resist chemistry will cease to be practical at sub-100-nm resolution. Multilayer resist schemes offer the capability of increased aspect ratio, but they add to the process complexity and cost. Encapsulated inorganic materials as resist components will be ultimately capable of sub-100-nm resolution with sufficient plasma etch selectivity. The encapsulated inorganic resist technology (EIRT) resist will act as a single layer hard mask compatible with existing resist processing steps. Material evaluation showed that encapsulated inorganic materials have properties compatible with current resist technology. Lithographic evaluations have been performed with electron beam, and with 248 nn and 157 nm projection systems. It was shown that 150-nm imaging is possible with resists having high inorganic material content. in all cases the EIRT resists have shown lithographic performance equivalent to control resists containing no SiO2. Reactive ion etch (RIE) etch rates in oxygen and chlorine plasmas are significantly reduced for resists containing SiO2 nanoparticles as compared to a commercial resist providing a proof of concept that EIRT resists can dramatically improved plasma etch rates.