LARGE-AREA ELECTRON-BEAM SOURCE

A new large-area electron-beam source which can operate continuously, stably, and indefinitely in a poor vacuum environment is described. This novel electron source produces a near monoenergetic electron beam which can uniformly expose large area substrates (i.e., 200 mm diam wafers and larger flat panel displays). The electron gun incorporates a cold cathode which is impervious to solvents and outgassing from irradiated polymer coatings. Unlike glow discharge electron sources, the accelerating voltage can be controlled independently of the emission current from the electron gun with a small bias voltage to a grid anode. Accelerating voltages of 1-60 keV and higher are possible. The principles of operation and performance characteristics of this new source are described, including its ability to expose insulating samples without requiring a conductive overcoat. This new electron source has enabled a number of new process innovations in photoresist stabilization, interlayer dielectric curing, lift-off processing, and pattern lithography.