A Simplified Fabrication Approach for PMMA Resists inElectron-Beam Lithography

Lithography is a core-pattern transfer technique in micro/nanofabrication, among which electron-beam lithography (EBL) is a representative example.Polymethyl methacrylate (PMMA) has been widely employed as an electron-beam resist due to its high sensitivity, high resolution, and excellent contrast.However, commercial PMMA resists are relatively expensive and have complex formulations, thereby limiting process flexibility and cost control.Here, we demonstrate a rapid, low-cost preparation method for a PMMA resist suitable for micrometer-scale EBL.PMMA powder was dissolved in anisole to obtain a 4 wt% solution, which was spin-coated onto substrates to form uniform and smooth thin films.To evaluate resist performance, a custom-designed 5 5 array pattern was used to systematically study the effect of exposure dose on pattern quality.Results show that doses below 200 C/cm 2 fail to induce complete scission of the PMMA molecular chains.Thermal evaporation and a lift-off process were employed to verify the dimensional accuracy of fabricated electrodes.Within the exposure dose range of 240-270 C/cm 2 , the electrode patterns were complete and exhibited straight edges.The optimal pattern fidelity was achieved at 260 C/cm 2 , with an absolute dimensional error below 0.2 m, meeting the precision requirements of most micro/nanofabrication applications.This work provides a practical process reference for the preparation of PMMA electron-beam resists and their application in nanodevice fabrication.