Proceedings Article | 11 April 2006
Munirathna Padmanaban, Andrew Romano, Guanyang Lin, Simon Chiu, Allen Timko, Frank Houlihan, Dalil Rahman, S. Chakrapani, T. Kudo, Ralph Dammel, Karen Turnquest, Georgia Rich, Scott Schuetter, Timothy Shedd, Gregory Nellis
Proc. SPIE. 6153, Advances in Resist Technology and Processing XXIII
KEYWORDS: Lithography, Polymers, Fourier transforms, Photoresist materials, Line width roughness, Immersion lithography, Line edge roughness, Thin film coatings, Photoresist processing, Semiconducting wafers
193 nm immersion lithography is rapidly moving towards industrial application, and an increasing
number of tools are being installed worldwide, all of which will require immersion-capable
photoresists to be available. At the same time, existing 193 nm processes are being ramped up using
dry lithography. In this situation, it would be highly advantageous to have a single 193 nm resist that
can be used under both dry and wet conditions, at least in the initial stages of 45nm node process
development. It has been shown by a number of studies that the dominant (meth)acrylate platform of
193 nm dry lithography is in principle capable of being ported to immersion lithography, however, it
has been an open question whether a single resist formulation can be optimized for dry and wet
exposures simultaneously.
For such a dry/wet crossover resist to be successful, it will need to make very few
compromises in terms of performance. In particular, the resist should have similar LER/LWR,
acceptable process window and controlled defects under wet and dry exposure conditions.
Additionally, leaching should be at or below specifications, preferably without but at very least with
the use of a top protective coat. In this paper, we will present the performance of resists under wet
and dry conditions and report on the feasibility of such crossover resists. Available results so far
indicate that it is possible to design such resists at least for L/S applications. Detailed data on
lithographic performance under wet and dry conditions will be presented for a prototype dry/wet
crossover L/S resist.
