(A) study on novel top surface imaging by selective adsortion of silicon surfactants

Abstract

Top Surface Imaging (TSI) has been an expected technology to improve resolution of optical lithography. TSI using gas phase silylation is the well-established method, but nowadays liquid phase silylation is more attractive alternative method. Liquid phase silylation has some advantage like the ease, improved silicon contrast and higher sensitivity. In this paper, the novel silylation method using polydimethylsiloxane-co-polyethylene oxide surfactants was studied for liquid phase silylation. In the novel silylation, silicon components of siloxane surfactants are incorporated in exposed matrix polymer resists through ion-ion interaction prior to $O_2$ -reactive ion etching ($O_2-RIE$). Siloxane cationic surfactants are attached carboxylic anion in exposed matrix polymer by columbic interaction. Silicon in adsorbed siloxane cations protect matrix polymer against $O_2-RIE$. Negative pattern is made. Adsorption effectiveness of cations depends on some factors, like structure, solubility and concentration of surfactants and characteristics of matrix polymers. For making good pattern, matrix polymers must be insoluble in surfactant aqueous solution. In this paper, for making insoluble matrix, two heat crosslinkable groups, epoxide and hydroxy was introduced in matrix polymer and reacted by heating.