AVS 59th Annual International Symposium and Exhibition
    Plasma Science and Technology Thursday Sessions
       Session PS-ThP

Paper PS-ThP7
On the Origin of the Line Width Roughness of Photoresist Patterns after Plasma Exposure

Thursday, November 1, 2012, 6:00 pm, Room Central Hall

Session: Plasma Science and Technology Poster Session
Presenter: R. Ramos, LTM (CNRS / UJF-Grenoble1 / CEA), France
Authors: R. Ramos, LTM (CNRS / UJF-Grenoble1 / CEA), France
M. Brihoum, LTM (CNRS / UJF-Grenoble1 / CEA), France
K. Menguelti, LTM (CNRS / UJF-Grenoble1 / CEA), France
L. Azarnouche, LTM (CNRS / UJF-Grenoble1 / CEA), France
M. Fouchier, LTM (CNRS / UJF-Grenoble1 / CEA), France
E. Pargon, LTM (CNRS / UJF-Grenoble1 / CEA), France
G. Cunge, LTM (CNRS / UJF-Grenoble1 / CEA), France
O. Joubert, LTM (CNRS / UJF-Grenoble1 / CEA), France
Correspondent: Click to Email
The control and minimization of the roughness on the sidewalls of transistor gates is a major aspect of the plasma patterning technology in microelectronics. The line width roughness (LWR) in the active layers is known to originate mostly from the transfer of the initial LWR of the photoresist patterns defined by 193 nm lithography. As a consequence, numerous plasma pre-treatments of the photoresist have been developed and applied to decrease the mask LWR prior to the plasma etching of the gate stack. However, the final LWR is still higher than the requirements for the next technological nodes. It is therefore necessary to develop a clear understanding of the physical mechanisms responsible for the modifications of the photoresist LWR during plasma exposure to further reduce the gate width roughness. In this work, we will show that plasma treatments of photoresist patterns result in the formation of a shell surrounding the pattern, i.e. including on surfaces not exposed to ion bombardment. The redeposition of by-products from the (photo)etching of the resist polymer plays a major role in the formation of this shell. We will highlight the influence of the mechanical properties of both the shell and the underlying modified photoresist on the LWR of plasma-exposed resist patterns. Based on the proposed mechanism, we will discuss the potential of pulsed plasmas for LWR reduction processes.