Clean mask shipping module development and demonstration for EUVL masks and blanks

Evaluation of protection schemes for extreme ultraviolet lithography (EUVL) masks against top–down aerosol flow

“…Extreme ultraviolet lithography (EUVL) is a strong candidate for the next lithography technology generation to achieve 32 nm nodes or smaller by utilizing a light of 13.4 nm wavelength (Gullikson, Tejnil, Liang, & Stivers, 2004;Hamamoto et al, 2005;Kim, Chang et al, 2006;Yan, He, Ma, & Orvek, 2006). Every EUVL mask must be assured of being free of particles prior to scanning exposure.…”

“…In the experiments, the particle size was limited down to about 100 nm, due to the lower detection limit of the wafer scanner used in this study. Since the EUVL masks need to be protected against all particles larger than approximately 30 nm in the case of 32 nm node technology (Yan et al, 2006), the evaluation of the protection schemes was extended down to 10 nm by a numerical simulation method. In order to numerically calculate the deposition velocity, the authors have employed a statistical Lagrangian particle tracking (SLPT) model which can handle various flow-todeposition-surface geometries in a two-dimensional axisymmetric domain, with the use of CFD software.…”

Experimental Investigations on Particle Contamination of Masks Without Protective Pellicles During Vibration or Shipping of Mask Carriers

“…They also tested the orientation of the mask carriers in the shipping container, namely, vertical or horizontal placements, and found that the horizontal shipment of the mask carrier with the mask critical surface facing down added very few particles larger than 60-nm equivalent size of polystyrene latex (PSL) spheres. The experiments of Yan et al [3], however, were limited to real shipments using mask blanks as witness plates. Therefore, methods for the feasibility studies to test mask contamination under some extreme conditions other than real shipping need to be developed to extract the clues of particle generation inside the mask carrier.…”

“…Yan et al [3] experimentally investigated the particle contamination of quartz mask blanks in several mask carrier models, by shipping them without protective pellicles. They also tested the orientation of the mask carriers in the shipping container, namely, vertical or horizontal placements, and found that the horizontal shipment of the mask carrier with the mask critical surface facing down added very few particles larger than 60-nm equivalent size of polystyrene latex (PSL) spheres.…”

“…Extreme ultraviolet lithography (EUVL), which is considered a strong candidate for the next lithography technology generation, utilizes radiation of very short wavelength of 13.4 nm to achieve 32-nm nodes or smaller [1], [2]. EUVL masks need to be protected against all particles larger than approximately 30 nm in the case of 32-nm node manufacturing [3]. The maximum allowable particle size would decrease as the feature size is further reduced.…”