General Physics Seminar 15 December 2005

"Multilayer research program on the ADC"

Andrey Yakshin
FOM Institute for Plasma Physics Rijnhuizen
P.O. Box 1207, NL 3430 BE Nieuwegein, The Netherlands


In current day commercial microlithography tools, printing integrated 
circuits is based on the optical projection of reticle patterns on wafers 
through demagnifying transmission optics. The projected pattern size is 
continuously decreasing due to the ever-present demand for higher numbers 
of devices per chip. This reduction of the pattern size calls for a 
reduction in the wavelength of the light used to project the pattern. Using 
transmission optics, a lower limit of the illumination wavelength is 
currently reached due to high absorption. A solution to this fundamental 
problem is to use reflective optics, instead of transmissive optics. Due to 
the low reflection amplitudes of single layers of materials at low 
wavelengths, reflective optics consisting of multilayers will be used for 
next generation lithography tools. 

In recent years, the main focus of the work has been on Mo/Si based 
multilayers for application in Extreme Ultra Violet Lithography (EUVL). 
Current limitations of EUV multilayers are due to reflectivity loss as a 
result if inter-diffusion between the layers and degradation of reflectance 
under high EUV fluxes. The Laser Plasma and XUV optics group at Rijnhuizen 
is recently running a FOM Industrial Partnership Programme 'XMO' (Extreme UV 
Multilayer Optics) which is focused on the physics for the 2nd generation of 
EUV multilayers. The objectives of XMO are studying deposition processes and 
plasma processing, chemical and diffusion barriers and surface photo-chemistry 
under EUV radiation. This seminar will present an overview of the program and 
recent research performed at LPX on the new multilayer deposition coater 'ADC'.