Studies On The Fabrication Of Master Mold For Soft Lithography By Focused Ion Beam Etching

Polydimethylsiloxane(PDMS) soft mold have an important application value in biological medicine and physical chemistry fields. PDMS soft mold of manufacturing derive from master mold structures. So the master mold structures of high resolution and high precision are the key to make the PDMS soft mold.At present, the methods of manufacturing master mold are Interferometric Lithography(IL) and Electron Beam Lithography(EBL) and so on, but these methods need spin coating photoresist, exposure, developing, fixer, reactive ion etching steps and the structures of processing are commonly quasi tree-dimensional structures.Based on the above situation, we use a method based on FIB to fabricate master mold for soft lithography. Tree-dimensional structures with an area of15?m×15?m as the master mold of elastic stamps are successfully manufactured on the silicon substrate through focused ion beam(FIB) etching.Trimethylchlorosilane(TMCS) as an anti-adhesion layer is spin coated on the silicon substrate, and PDMS prepolymer is spin coated on the TMCS and then replicate the micro three-dimensional structures of what complementary with Si specimen.The Si specimen surface hydrophobic property is tested by the contact angel measurement instrument and the PDMS surface structures are tested by AFM.The results show that the feature structures are transferred effectively. The structure of 15?m×15?m of the cylinder small size structure is 713.56 nm, and the height of the cylinder is 51.39 nm also transferred. When we dilute PDMS using heptane, the aspect ratio can reach 1:1. Compared with other traditional methods,the procedure of making the three-dimensional structures is simpler and shorter preparation period, it is an effective method of making master mold for soft lithography.The successful fabrication of the master of elastic stamps by FIB etching technology contribute to explore the smaller sizes and the application of the micro-nano structure devices.