Different technologies have been explored for fabricating silicon nanopillars (SiNPs). One of the emerging technologies is the combined fabrication process based on silica nanoparticle lithography and metal-assisted chemical etching (MACE). However, the process flow to fabricate successfully SiNPs depends on various technology factors. We report investigations on factors affecting the fabrication technology, from the assembly of close-packed silica nanoparticle monolayers using drop-coating method, formation of nonclose packed silica nanoparticle monolayers using HF vapor etching, to creation of SiNPs using MACE. Etching mechanisms are suggested to explain observed experiment results.