Hexanedithiolate/decanethiolate mixed monolayer protected gold clusters (DC6/C10-MPCs) with an average core diameter of 1.78 +/- 1.1 nm and with an average composition formula Au-174(S(CH2)(9)CH3)(31)-(S(CH2)(6)SH)(19) have been synthesized through a phase transfer method, and cluster monolayer films were formed by self-assembly of the clusters on Au(111) surface. Both the clusters and the monolayer films were characterized by absorption spectra, Fourier transform infrared reflection spectroscopy, H-1 NMR spectroscopy, elemental analysis, differential scanning calorimetry and thermogravimetry, transmission electron microscopy, and scanning probe microscopy. Some geometrically well-defined patterns have been made on the cluster film surface by scanning tunneling microscopy (STM) lithography, and detailed etching conditions were investigated. It was found that STM directed patterning on the cluster film surface was mechanically controlled.