Resist characteristics of acryl polymers for 193nm lithography

Abstract

The control of line edge roughness &ER) in patterned resist lines is a major challenging topic in manufacturing of semiconductors [l, 21. Therefore, there are numerous reports of fundamental challenges in desipng materials and resist processing parameters to reduce LER [3-71. In the past, we have reported the effect of protect% group of polymer materials on lithographic performance [X-1 01.These results suggest that alkoxy-methyl protectins group is effective for M h e r controllug LER.Preparing three dfferent copolymers AdOMMA-co-GBLMA, MAdOMM.4-CO-GBLMA and MAdMA-co-GBLM.4 as shown in Figure 1, we have evaluated copolymers properties, resolution and LER. Table 1 shows the thermal properhes of AdOMMA-co-GBLM4 MAdOMMA-co-GBLMA and MAdMA-CO-GBLMA. As compared with MAdMA copolymer, AdOMM,4 and MAdOMMA copolymm inhcated lower plass transition temperature (Tg). Side chain elasticity of alkoxy-methyl ester group reduces the T g by about 20-27 "C as seen with the 2-a-ylo?cy methyl (AdOM) group and I-methyladamantyloxy methyl (MAdOM) in the copolymers. We confirmed the dlfference of the acid-catalyzed &protection reactivity between alkoxy-methyl ester group and tertiary alkyl group (MAd) in these resists film using Fourier transform ineared (FT-IR) spectroscopy. In comparing the protecting groups of AdOM, MAdOM and MAd, it is found thal alkoxy-methyl ester group (AdOM ancl MAdOM) improves LER at two PEB bake conditions of 100°C and 120°C. The relationshp between LER and mfferent protecting groups are shown in Figure 2. Furthermore, we will correlate the thermal propeaies, acid-catalyzed deljrotection reactivity and dissolution propeaies of these polymers with the surface morphologes during development observed through atomic force microscope (,4FMj by the time ofthe conference. A&~MMA-C&GBLMA MA~DMMA.cDGBLMA M A m A CO GELMA Figure 1. Structure of AdOMMA-co-GBLMA, MAdOMM.4-CO-GBLMA and M4dMA-co-GBLhL4