There are many considerations to the design of BARC materials. Among those many properties, one important property that can effect lithographic performance is BARC coating uniformity. In general, the basic coating property (conformal or planar) depends on basic characteristics of polymer (Mw, chemistry, etc). But another major factor to control the coating uniformity is the choice of solvent system in the formulation of the BARC. According to our experimental results, two major factors that can affect the coating uniformity of one BARC are the vapor pressure and the hydrophilicity of solvents. If any solvent has too high vapor pressure and high hydrophilicity relatively, polymer segregation occurs in BARC surface area in case of high humidity condition, resulted in bad coating uniformity.
In this paper, we will show basic evaluation results including the morphology change of BARC surface with several solvents which can be used in BARC formulation according to various humidity and temperature conditions. And also we will show the solution to overcome this problem in device manufacturing.
The ArF resist has been evaluated focusing on resin character such as molecular weight, monomer composition and polydispersity (Pd). The resin properties were investigated to elucidate that which parameter was affected to the line edge roughness (LER). The Pd was correlated with LER. As the Pd was large, the LER was small. The resin molecular weight and monomer composition were affected to their vertical profile. Low molecular weight portion rich resin resulted in round and t-top profile, whilst high molecular weight rich resin resulted in square profile. The amount of lower molecular weight fraction was changed by purification method. The lower molecular weight resin caused severe tapered profile. It was concluded that 1) shift of Mw to smaller and 2) higher content of low molecular size fraction lead to rounded and tapered pattern profile. Lot-to-lot stable good pattern profile has achieved by controlling polymer molecular weight and content of low molecular size fraction in small variation range.