Preparation of solution-processable polybenzoxazole-graphene nanocomposites for etching mask with high etching resistance

Abstract

In the advanced lithography processes of chip industry, the relatively deficient etching resistance and pattern distortion phenomena of spin-on hardmask (SOH) on dry etching process have emerged as new major issues. We tried to overcome the obstacles by applying the graphitic carbon materials with high mechanical strength to the SOH polymer. The graphene-polymer (nGO-FPHA) composites were prepared by chemical coupling reaction of fluorinated poly(hydroxyamide) (FPHA) and acyl-chloride-functionalized graphene oxide of submicron size (nGO). The nGO-FPHA showed stable dispersion in some organic solvents, and finally changed to rigid nRGO-FPBO under heat after spin-coating the solution on substrates. According to the investigation of nRGO-FPBO, the homogeneous dispersion and reduction of nGO sheets helped to enhance the properties and performance of composite film as much as 72 %, 56 %, and 54 % of elastic modulus, hardness, etch resistance from pure FPBO polymer, respectively. In addition, the nRGO-FPBO showed a good thermal stability below $400 \circ C$ so that the composite film can be used to high temperature processes.