Development of resist material and process for hp-2x-nm devices using EUV lithography

Abstract

Extreme ultraviolet (EUV) lithography is the leading candidate for the manufacture of semiconductor devices at the hp-22-nm technology node and beyond. The Selete program covers the evaluation of manufacturability for the EUV lithography process. So, we have begun a yield analysis of hp-2x-nm test chips using the EUV1 full-field exposure tool. However, the resist performance does not yet meet the stringent requirements for resolution limit, sensitivity, and line edge roughness. We reported on Selete standard resist 4 (SSR4) at the EUVL Symposium in 2009. Although it has better lithographic performance than SSR3 does, pattern collapse limits the resolution to hp 28 nm. To improve the resolution, we need to optimize the process so as to prevent pattern collapse. An evaluation of SSR4 for the hp-2x-nm generation revealed that a thinner resist and the use of a TBAH solution for the developer were effective in mitigating this problem. Furthermore, the use of an underlayer and an alternative rinse solution increased the exposure latitude by preventing pattern collapse when the resist is overexposed. These optimizations improved the resolution limit to hp 22 nm.

Applicability of extreme ultraviolet lithography to fabrication of half pitch 35nm interconnects

“…Figure 15 shows the ultimate resolution obtainable with Selete Standard Resist 4 (SSR4) 21 and the EUV1. The thickness was 40 nm; an alternative developer, namely, tetrabutylammonium hydroxide (TBAH), 22 was used; and dipole illumination 23 was employed.…”

Towards production ready processing with a state-of-the-art EUV cluster

“…At the size regimes in question, it is difficult to achieve aspect ratios >1 with only aqueous developers and rinses, as the surface tension of the drying water will collapse the patterns onto their neighbors 6,7 . Two alternative techniques to improve pattern collapse margins that do not require significant tooling modifications include using surfactant rinses to reduce surface tension 8-10 as well as alternative develop chemistries [11][12][13] . Here we have focused on the first technique, introducing surfactinated FIRM TM rinses just before the drying step to reduce surface tension, and thus pattern collapse.…”

Studying the mechanism of hybrid nanoparticle EUV photoresists

“…Research in short wavelength lithography, especially for extreme ultraviolet lithography (EUVL), is attracting considerable attention [1][2][3][4][5][6][7][8][9][10] . The next generation EUV photoresists should combine high etch resistance, high imaging quality and appropriate light absorption.…”