Development of a standalone zoneplate based EUV mask defect review tool

Since the beginning of lithography using a reticle, defects have been one of the key factors in determining reticle quality and wafer yields. With the rapid adoption to EUV Lithography and the high cost of existing EUV mask defect review systems there is an industry need for an alternative defect review and dispositioning system. To meet this need Micron Mask Technology Center, the supplier of state-of-the-art mask technology, has partnered with EUV Tech, the world’s leading supplier of EUV Metrology equipment, to develop a standalone Zoneplate-based EUV wavelength microscope. EUV Tech has introduced and delivered the AIRES (Actinic Image REview System), an at-wavelength EUV Mask Defect Review Tool for EUV photomasks. The tool features EUV Tech’s patented zone plate imaging system equipped with the EUV Tech’s automated mask transfer system to the process chamber. AIRES is based on the successful Zoneplate EUV Microscope at Lawrence Berkeley Lab called SHARP which has been used to support semiconductor development for over a decade. AIRES is the first commercial standalone EUV projection imaging zoneplate microscope supporting photomask defect review and dispositioning to support EUV high volume manufacturing. In this paper, we introduce the tool and its performance with defect cases and pattern imaging application on EUV production reticles.