Performance of a dry 193nm resist under wet conditions

Munirathna Padmanaban, Andrew Romano, Gu anyang Lin, Simon Chiu, Allen Timko, Frank Houlihan, Dalil Rahman, S. Chakrapani, T. K udo, Ralph R. Dammel, Karen Turnquest*, Georgia Rich*, Scott D. Schuetter**, Timot hy A. Shedd**, Gregory F. Nellis** AZ Electronic Materials, 70 Meis ter Avenue, Somerville, NJ 08807 *International SEMATECH, 2706 Montopolis Dr., Austin, Texas 78741 **Computational mechanics center, Uni versity of Wisconsin-Madison, WI 53706 Abstract 193 nm immersion lithography is rapidly moving towa rds industrial application, and an increasing number of tools are being installed worldwide, all of which will require immersion-capable photoresists to be availa ble. At the same time, existing 193 nm processes are being ramped up using dry lithography. In this situ ation, it would be highly a dvantageous to have a si ngle 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 studi es 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 specifica tions, preferably without but at very least with the use of a top protective coat. In this paper, we will present th e 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.