Through-focus EUV multilayer defect repair with nanomachining

Evaluation of multilayer defect repair viability and protection techniques for extreme ultraviolet masks

“…Micromachining was introduced to address multilayer defects and attempts to correct for the phase effect by judicious removal of multilayer material. [13][14][15] Despite promising results from prior studies, considerations for HVM and lifetime durability of micromachined repair sites have remained largely unexplored. In particular, exposed multilayer sidewalls have been shown to significantly degrade after several mask cleans.…”

Analysis of extreme ultraviolet mask defect inspection based on complex amplitudes of the aerial images

“…Amplitude defects located at the top of the multilayer will directly affect the absorption or scattering of EUV light and reduce the reflectivity of the multilayer [2]. Phase defects exist in the substrate or inside the multilayer, causing deformation of the multilayer and thus affecting the amplitude and phase of the mask reflection field [6]. In EUV lithography, due to the reduction of exposure wavelength and the reflection characteristics, the EUV mask has unique phase defects [7].…”

Multilayer defect compensation based on three dimensional absorber correction in EUV lithography

“…In EUV lithography, the mask acts as an optical component and has a large potential impact on the aerial image [3]. Multilayer defects of EUV lithography mask may cause severe reflectivity deformation and phase shift in advanced nodes, resulting in local intensity loss of the print image and asymmetric through-focus printing [4] [5]. Figure 1 presents the impact of a simulated pit defect(htop=-5nm, ωtop=90nm, hbot=-5nm, ωbot=90nm) on the printing of a 40 nm line-space pattern.…”

“…To compensate for the asymmetric through-focus printing effect and the intensity loss, several compensation methods have been proposed. McIntyre et al proposed through-focus multilayer defect repair method with nanomachining [5]. The combination of multilayer material removal and absorber modification methods is used to compensate for the impacts of the bump defects, and deposition of the phase-shifting material is adopted to adjust the phase effects of the pit defects [5].…”