Frank Eisert

Mirror substrates for EUV lithography: progress in metrology and optical fabrication technology

In this paper, the metrology and fabrication concepts at Carl Zeiss will be reviewed. The present status in the fabrication of specific EUVL mirrors will be reported as well.

Fabrication and metrology of diffraction limited soft x-ray optics for the EUV microlithography

EUVL, i.e. microlithography at 13nm is one of the most likely technologies to satisfy the requirements for the 45nm-node and below of the IC-manufacturing roadmap. The development of the first step and scan machines meeting production requirements of field size and resolution is in progress. A key component of these machines will be a diffraction limited, off-axis mirror system with aspherical surfaces. The optical surfaces of these mirrors have to be fabricated and measured with unprecedented accuracy. In recent years, technology development at Carl Zeiss SMT AG was focussed on the on-axis aspheres of the NA=0.30 micro exposure tool (MET). Presently this technology is transferred to the surfaces of a NA=0.25 off-axis, large field system The current status of the fabrication and metrology of both on-axis and off-axis mirrors will be reviewed.