Wet-silylation Process for X-ray and EUV Lithographies.

Abstract

A wet-silylated and dry-developed resist process for proximity X-ray and broad-band EUV (13-40nm) lithographies is investigated in order to overcome pattern collapse during wet development and to delineate finepitch and high-aspect-ratio patterns. In addition, the applicability to sub- 0.1-μm patterning is discussed. Imaging experiments for proximity X-ray lithography are performed using a synchrotron radiation (SR) light source from the beamline (BL-A1) at the SORTEC ring, and those for broad-band EUV lithography are performed using 32:1 reduction Schwarzschild optics illuminated with the SR light source from the beamline (BL-D2). The silylation solution consists of B[DMA]DS (bis(dimethylamino)dimethylsilane) or HMCTS (hexamethylcyclotrisilazane) as the silylating agent, MCA (methyl cellosolve acetate) as the diffusion promoter and a solvent xylene. Silylation characterization and determination of the optimum composition of the silylation solution have been performed using Fourier transform infrared spec roscopy (FTIR) measurement. Using the optimal wet-silylation and dry-developed resist system, 0.08-μm lines and spaces of a 0.5-μm-thick resist (aspect ratio=6) in proximity X-ray lithography, and 0.1-μm lines and spaces of a 0.55-μm-thick resist (aspect ratio=5.5) in broad-band EUVL can be successfully delineated. High resolutions of_??_0.1μm show that the silylation process for proximity X-ray and EUV lithographies is applicable to sub-0.1-μm lithography with a single-resist scheme.