|
Extreme Ultra Violet Lithography (EUVL) has been widely regarded as the lithography technology to succeed
optical lithography. It is now considered as one of the most promising technologies below hp45nm node [1], following
ArF immersion lithography considering trend of achievable process K1 factors. In this paper we would like to present
our significant progress on the development of EUV exposure tool. There are several key important areas which should
be developed to realize EUVL to be feasible, such as reflective mask, resist, and tool itself. The reflective mask features
such characteristics as pellicle-less, ultra-smooth blank flatness and defect free. The resist should be of high sensitivity
and small line edge roughness (LER) as well as fine resolution. EUV exposure tool itself consists of major modules
such as EUV light source, projection optics, vacuum body, vacuum stages, and so on. Nikon has developed new
polishing technologies such as ion-beam figuring and elastic emission machining, and new ultra high-precision
interferometers for aspheric surface metrology. Our multi-layer coating technology has been also improved. High
reflective Mo/Si multi layer coating has been successfully achieved and irradiation tests using synchrotron radiation
have been conducted. Successful achievement of those developments enables us to produce full-field projection optics
for EUVL process development tool called EUV1. The proto-type development of full-field projection optics has been
successfully completed and its technical achievement has reflected into production optics. Preparation of complete set
of production and metrology tools necessary for projection optics production was completed and all tools are now in
full operation.
Nikon has already developed dual pod reticle carrier for EUV1 tool. In parallel Nikon has been developing the
same concept carrier for HVM in cooperation with Canon and Entegris.
Regarding to EUV1 tool development, all modules of EUV1 such as full-field projection optics module,
illumination optics module, vacuum body module, vacuum compatible reticle/wafer stage modules, reticle/wafer loader
modules, EUV light source module have been completed. Nikon has already started EUV1 module installation process
and the module level function and basic performance have been being checked. Nikon will complete module integration
to achieve the first exposure result. Some development results will be shown which lead to confidence for realization of
EUVL. Nikon also would like to announce that development of 1st generation production EUVL tool named EUV2 has
been studied.
|
