A SIMPLE FABRICATION PROCESS OF T-SHAPED GATES USING A DEEP-UV ELECTRON-BEAM/DEEP-UV TRI-LAYER RESIST SYSTEM AND ELECTRON-BEAM LITHOGRAPHY/

A new fabrication process of T-shaped gates has been developed using a deep-UV/electron-beam/deep-UV (DUV/EB/DUV) tri-layer resist system an d electron-beam lithography for the first time. The simple process acc omplished a submicron T-shaped gate by a single exposure and a single development step. The narrow/wide/narrow opening of the DUV/EB/DUV res ist structure can be accurately controlled by the e-beam dosage and th e development conditions. Differences in the sensitivities of the DUV resist and the EB resist were investigated. Due to the lower sensitivi ty of the adopted DUV resist to the electron beam, the smaller opening of the DUV resist layer was obtained. The higher sensitivity of the E B resist resulted in a wider opening in the middle resist layer. A 0.1 5-mu m-gate-length T-shaped gate can be easily formed by the short-pro cess-time and low-production-cost hybrid DUV/EB/DUV resist approach.