Proceedings Article | 8 December 1995
KEYWORDS: Photomasks, Reticles, Etching, Optical alignment, Manufacturing, Lithography, Printing, Critical dimension metrology, Dry etching, Laser applications
The integration of an advanced high resolution laser lithography system for sub-0.50 micron technology, utilizing a 32 beam, 8 pass exposure writing strategy, in a merchant production mask-making environment, is explored. The ALTA-3000 tool represents the latest evolution of mask lithography platforms and, as such, has several advantages over the traditional e-beam or CORE exposure systems. For example, on a laser tool there is no requirement for a high vacuum system, and the complexities associated therein. Unexposed masks are not carried in individual cassettes, as in an e-beam system, and therefore system performance is not subjected to these error sources. Freedom from the potentially adverse affects of these sub- systems should appear as improvements on product performance in the areas of registration and defect control. The additional gray scales of the 32 beam architecture enable increased averaging of the individual beams, thus leading to improvements in print performance, relative to earlier versions of laser technology. The production capability of the ALTA-3000 is analyzed to determine what type of routine performance can be expected in terms of resolution, linewidth control, linearity, registration, defect control, and printing speed. The primary goal of this evaluation is to determine if the performance of the system is capable of meeting reticle requirements for 64 and 256 megabit chips and 5th and 6th generation microprocessors, which are expected to require 0.35 and 0.25 micron geometries on the wafer. The evaluation revealed the basic capability exists, however, additional work must be done in the area of registration control to improve the yields necessary to support high volume production for these technologies.
