Experimental demonstration of a prototype maskless micro-ion-beam reduction lithography system

In addition to the enormous cost savings from mask development, defect detection, and defect correction, a lithographic technology which can delineate patterns without employing any mask steps---called a maskless lithography system---would also offer improved flexibility for rapid implementation of new designs and higher throughputs due to time savings from the elimination of multiple mask steps. In this work, the rationale for a post-optical lithography technology of choice, namely the Maskless Micro-ion-beam Reduction Lithography (MMRL) system, is derived based on the diffraction-limited resolution of the Rayleigh criterion on photolithography as compared to ion-beam projection lithograph (IPL)---which is virtually diffraction free and suffers little scattering and proximity effects. Furthermore, trade-off considerations for numerical apertures, depth of focus, and resist technologies are analyzed in context of the prospective next-generation lithography (NGL) technologies. The work culminates in the design and demonstration of an experimental prototype system that can potentially surmount the critical mask- and linewidth-related issues of current and proposed NGL technologies.; The merits of MMRL is based in parts on the performance the radio-frequency (RF)-driven multicusp plasma ion source, which has been adopted by conventional IPL for the same qualities---namely: low energy spread and therefore low chromatic aberration; high atomic ion species in the beam; and uniform plasma density in a large illuminating area. Among charged particle systems, the maskless approach of the MMRL system is the more advantageous because it eliminates the need for masks along with the preceding optics for illuminating the masks. Here, the microfabrication technologies enabling the unique maskless approach of the MMRL system via an electronic pattern generator are also presented.; The overall MMRL prototype system consists of a multicusp plasma source, a pattern generator, an all-electrostatic ion optical column with an image demagnification factor of 10, and a computer-controlled high-precision x-y-z stage that moves wafer substrates across the stationary ion-beam for exposures at different locations on the wafer. Ion beams of up to 99% atomic hydrogen ions (H+) can be obtained with the inductively RF-powered multicusp plasma ion source with less than 1% variation in radial ion density profile. (Abstract shortened by UMI.)...