Lithographic processing of polymers using plasma-generated electron beams

Pattern definition in polymer films is achieved using electron beams generated in soft vacuum (0.05-0.50 torr) glow discharges either on a continuous or a pulsed (20-100 ns) basis. With the continuous-mode electron beam, 7- mu m transmission mask features are replicated in both polymethyl methacrylate (PMMA) and polyimide resists. Using a pulsed electron-beam submicron ( approximately 0.5 mu m) features are transferred from an electron-transmitting stencil mask into the PMMA. The soft-vacuum pulsed electron beam is also eminently suited for polymer stabilization. Pulsed electron-beam hardening of 0.05-3.5 mu -thick AZ-type and MacDermid resist patterns is also demonstrated with hardened resist patterns stable to temperatures between 200 degrees and 350 degrees C. The demonstrated replication and pattern stabilization technique may be applicable in microelectronics packaging lithography where the resist thickness is substantial, linewidths are 1-10 mu m, and registration requirements are less stringent.<
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