50 nm resolution, defect-free, electron-beam resists produced with monomer/polymer multilayer films

Abstract

Recent technological advances in very large scale integration (VLSI) are beginning to outstrip the technology used to produce these circuits. Ultraviolet and optical lithography techniques are producing resist patterns with resolutions approaching the expected minimum. Application needs demand that this minimum be improved to achieve more features per unit area of circuit. We have achieved a potentially major breakthrough towards improving the resolution of resist patterns. Through the use of monomer/polymer multilayers, line resolutions produced by way of a novel computer-controlled electron beam technique is now possible. The relative ease and high reliability of multilayer formation ensures uniform films of a thickness an order of magnitude less than spin cast film thicknesses. The high electron sensitivities of these films enables excellent degradation (or polymerization) upon exposures to an electron beam. Final pattern resolution, for both positive and negative resists, is an order of magnitude higher than conventional resist resolutions, offering possible improvement in circuit capability. Morphological studies of these multilayer films provide unique information on domain size and structure. The ultimate morphology of these films is shown to be dependent on deposition conditions as well as the substrate used.