SBIR Phase II: High-resolution, high-precision 193-nm photomask phase metrology system

该小型企业创新研究(SBIR)二期项目旨在设计和构建一套适用于高级相移光掩模测量的超高分辨率、高精度相移综合测量系统。许多半导体制造商现在希望使用193 nm的曝光波长从90 nm节点发展到45 nm节点。印刷这些亚波长特征需要先进的光刻技术。移相光掩模，即控制光学厚度和不透明度的掩模，是一种关键的掩模增强技术。对临界层相移掩模进行快速而准确的测量对于工艺控制和修复验证都是必要的，但使能工具还不存在。这一二期计划的目标是将一期建成的光化高重复频率激光器集成到干涉激光显微镜中，包括稳定的相移干涉仪和激光显微镜的设计、建造和集成，以及相移干涉测量信号处理算法的整合和优化。集成光学系统将实现先进光掩模的相位计量，具有国际半导体技术路线图(ITRS)、掩模制造商和掩模用户所要求的测量精度和空间分辨率。在商业上，第二阶段光掩模相位计量系统的主要受益者是半导体光学光刻行业。90 nm及以上节点的ITRS‘路线图’要求测量光掩模光程差，精度低于0.4度。这种计量必须在与相应技术节点的特征大小一致的空间分辨率尺度上进行，并且对于孤立和密集的结构都是如此。目前还没有满足这些需求的商业计量工具。第二阶段高精度计量系统将使制造商能够表征、预测和控制掩模加载效应以及对可靠制造相移掩模至关重要的其他修复和工艺控制问题。集成的相位测量系统也有可能在纳米MEMS测试和其他纳米尺度干涉测量领域得到应用。

This Small Business Innovation Research (SBIR) Phase II project aims to design and construct an ultra-high-resolution, high-precision phase-shift integrated measurement system suitable for metrology of advanced phase-shifting photomasks. A number of semiconductor manufacturers now expect to progress from the 90 nm through the 45 nm nodes using an exposure wavelength of 193 nm. Advanced photolithographic techniques are necessary to print these sub-wavelength features. Phase-shifting photomasks, i.e. those in which the opticalthickness, as well as the opacity is controlled, are a key reticle enhancement technology. Fast and accurate metrology of critical-layer phase-shift masks is becoming necessary both for process control and repair validation, but the enabling tools do not yet exist. The goal of this Phase II program is to integrate the actinic high-repetition rate laser built in Phase I into an interferometric laser microscope involving the design, construction, and integration of a stablephase-shifting interferometer and laser microscope, and the incorporation and optimization of phase-shifting interferometry signal processing algorithms. The integrated optical system will enable phase metrology on advanced photomasks, with the measurement precision and spatial resolution required by the International Technology Roadmap for Semiconductors (ITRS), mask makers and mask users. Commercially, the primary beneficiary of the Phase II photomask phase metrology system is the semiconductor optical lithography industry. The ITRS 'roadmap' for the 90-nm node and beyond requires measurements of photomask optical path difference with sub-0.4 degree precision. This metrology must be performed at spatial resolution scales consistent with feature sizes of the respective technology nodes, and for both isolated and densely-packed structures. No commercial metrology tools yet exist which satisfy these demands. The Phase II high-precision metrology system will enable manufactures to characterize, predict, and control mask-loading effects and other repair and process control issues essential to the reliable fabrication of phaseshifting masks. It is also likely that the integrated phase metrology system will find utility in the area of nano-MEMS testing and other nano-scale interferometry.