The objectives of BOLD are to build and test two lithographic systems that will enable the evaluation of high numerical aperture (NA) optics and scan-and-repeat technology with a resolution in the sub-0.3 micron range.
A prototype wafer stage optical lithography system with high accuracy and high speed based on novel principles has been realized. A new motor concept has been introduced and is being evaluated, as are new alignment and interferometry systems. The basic design and technology for the step and scan lens have been established, and the effects of a finite laser bandwidth on the lens performance have been calculated. Market requirements for 0.25 micron scanning systems have been considered, and based on this a system outline for a production step and scan system has been drawn up. Simulation is being used to study the effects of the source and illumination characteristics on the overall performance. User inputs are continuously refined and updated, and are considered in the overall planning.
Projection systems with very high NA at short wavelengths will be designed and a prototype lens system built. The possibilities of scan-and-repeat and other photocomposition methods will be investigated, with the emphasis placed on accommodating large chip sizes for future ASIC devices. The most critical subsystems (high-precision synchronised wafer and reticle stages) will be built and tested in a laboratory system. System requirements will be provided by a user group, and the resolution and overlay of the new techniques evaluated.