The feature scaling and patterning control required for the 7nm node has introduced EUV as a candidate lithography technology for enablement. To be established as a front-up lithography solution for those requirements, all the associated aspects with yielding a technology are also in the process of being demonstrated, such as defectivity process window through patterning transfer and electrical yield. This paper will review the current status of those metrics for 7nm at IBM, but also focus on the challenges therein as the industry begins to look beyond 7nm. To address these challenges, some of the fundamental process aspects of holistic EUV patterning are explored and characterized. This includes detailing the contrast entitlement enabled by EUV, and subsequently characterizing state-of-the-art resist printing limits to realize that entitlement. Because of the small features being considered, the limits of film thinness need to be characterized, both for the resist and underlying SiARC or inorganic hardmask, and the subsequent defectivity, both of the native films and after pattern transfer. Also, as we prepare for the next node, multipatterning techniques will be validated in light of the above, in a way that employs the enabling aspects of EUV as well. This will thus demonstrate EUV not just as a technology that can print small features, but one where all aspects of the patterning are understood and enabling of a manufacturing-worthy technology.
Recently, Multi-Beam Mask Writer (MBMW) scheme is newly considered for next generation writing scheme. As the
MBMW writing uses many multi-array bundle beams with small spot size, the fast writing and complex pattering is
The target dose level of MBMW is high around 100μC/cm2 and the target of total writing time is within 10 hours for
next generation layout with complex and small node pattern. The risks of high dose writing are rising of blank
temperature, chemical reaction with photo-resist and charging effects in blank. In addition, the fast writing can cause the
rising of temperature in blank.
The heating effect can be divided into local and global terms, and each effect of critical dimension (CD) and
registration was analyzed by heating effect. In case of MBMW, the global heating is more critical than local heating.
Therefore, we need to study about the global heating effect which can affect global registration in MBMW.
In this paper, we study about the global heat distribution on mask blank in certain MBMW writing condition, and the
directional deformation of blank which can affect global registration was analyzed by using Finite Element Method
(FEM). We approach with two kinds of modified heat model and the FEM model was verified with analytical calculation.
The temperature variation and deformation distribution were achieved with transient method with the writing
conditions, in case of 100μC/cm2 of total dose, 50kV of acceleration voltage, 100% of chip density and 10 hour of total writing time. Therefore, we can consider the writing conditions according to mask specification in MBMW scheme.