Spin-on organic hardmask for topo-patterned substrate

Abstract

Carbon rich hard mask underlayer (UL) material deposition has become inevitable process in all advanced lithography applications. UL processes which include chemical vapor deposition (CVD) and spin-on UL play a very important role for pattern transfer from patterned thin photoresist to the substrate. UL materials must satisfy several requirements, which have become more demanding with device shrinkage and increasing device complexity (FinFET, 3D integration). The most important properties of next generation UL materials are superior wiggle resistance, etch controllability, thermal resistance, planarization, and gap filling performance. In particular, planarization and gap fill properties of UL material for application on topo-patterned substrate are receiving much attention recently. CVD processes generally give better wiggle performance and thermal resistance, but poorer planarization and gap filling performance than spin-on UL processes. In addition, Cost of Ownership (CoO) of CVD process is higher than that of a spin-on UL process. Therefore spin-on organic hard mask (OHM) process has been investigated as an attractive alternative to CVD processing. In this paper, we focus on an investigation of key properties of spin-on UL materials for achieving good planarity and gap filling performance on topo-patterned substrate. Various material properties such as solution viscosity, glass transition temperature (Tg), and film shrinkage ratio were evaluated and correlations between these properties and planarization were discussed.

Surface Transformation of Spin-on-Carbon Film via Forming Carbon Iron Complex for Remarkably Enhanced Polishing Rate

“…However, as the ACL process is conducted by CVD at a high temperature, it is confronted by a high generation of organic particles, a high film surface roughness, a difficulty of CMP due to a high hardness, and a high process cost, as shown in Figure S2 . As an alternative, SOC film has been applied as a hard-mask, as it can provide a cheap process cost, a low film surface roughness, and a high process flexibility to adjust the film thickness, hydrophilicity, absorbance, and refractive index, because of the spin-coating process of a polyarylene-ether block copolymer solution at room temperature [ 14 , 15 , 16 ]. Nevertheless, as the hardness of an SOC film (i.e., ~0.63 GPa) is remarkably lower than that of an ACL (i.e., ~6.51 GPa), the SOC film thickness should be relatively thicker than the ACL thickness to assure chemical, heat, and anisotropic etching resistance.…”