Advanced mask aligner lithography (AMALITH)

摘要

Mask aligners were the dominating lithography tool for the first 20 years of semiconductor industry. In the 1980sindustry changed over to projection lithography. However, mask aligners were never sorted out and still today hundredsof new mask aligners are sold each year. This continuing success of mask aligner lithography is due to two basic trendsin lithography: (a) Costs for leading-edge lithography tools double approximately every 4.4 years; and (b) the number oflithography steps per wafer was increasing from a few litho layers to more than 35 layers now. This explains why maskaligners, a very cost-effective solution for uncritical litho layers, are still widely used today. In over 50 years ofsemiconductor industry the mask aligner system has changed tremendously. However, only little effort was undertakento improve the shadow printing process itself. We now present a new illumination system for mask aligners, the MOExposure Optics (MOEO), which is based on two microlens-type Köhler integrators located in Fourier-conjugatedplanes. The optics stabilizes the illumination against misalignment of the lamp-to-ellipsoid position. It providesimproved light uniformity, telecentric illumination and allows freely shaping the angular spectrum of the illuminationlight by spatial filtering. It significantly improves the CD uniformity, the yield in production and opens the door to a newera of Advanced Mask Aligner Lithography (AMALITH), where customized illumination, optical proximity correction(OPC), Talbot-lithography, phase shift masks (AAPSM) and source mask optimization (SMO) are introduced to maskaligner lithography.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.