SBIR Phase II: A Simple and Practical Solid-State 157nm and 193nm Coherent Light Source for Applications in Lithography Development

SBIR二期项目将开发新一代157nm和193nm的全相干固态真空紫外（UV）光源，以支持下一代半导体制造和计量以及基础研究中的应用。目前可用的紫外线准分子源有局限性，如空间相干性差，使其不适合计量。因此，产生全空间相干紫外光源最有希望的途径是对光谱中可见-红外区域的光进行上转换，在该区域已经存在相干激光源。然而，实现这一目标的一个重大技术障碍是缺乏在深紫外下工作的可靠的固态非线性光学晶体。200nm波长处不可避免的残余吸收会导致非线性光学晶体的长期损伤，需要不断更换。此外，对于193nm频率，目前还没有合适的非线性光学晶体。因此，气体非线性光学介质是产生波长200nm光的有吸引力的晶体替代品。SBIR第二阶段项目将在充满气体的空心波导中使用四波混频来开发一种台式VUV激光器，该激光器能够在157nm和193nm的完全相干光束中产生10兆瓦，甚至100兆瓦的光，其重复频率非常高（10kHz），用于计量应用。这个项目有可能对半导体和电子工业以及基础科学产生非常广泛的影响。微处理器、DRAM存储器和其他集成电子产品的复杂性和速度的进步是由制造越来越密集的集成电路的能力所驱动的，其特征尺寸也越来越小。这得益于高分辨率光刻“步进器”的发展和光刻中波长更短的光的使用。由于目前还没有明亮的桌面光源，大多数短波材料、纳米和化学科学都必须在同步加速器光源上进行，而同步加速器的使用受到限制，光源也没有得到优化。因此，有了这种资源，生产力就会显著提高。

This SBIR Phase II project will develop a new generation of fully-coherent, solid-state, vacuum-Ultraviolet (UV) light sources at 157nm and 193nm, to support the next generation of semiconductor fabrication and metrology, as well as for applications in basic research. Currently available UV excimer sources have limitations such as poor spatial coherence, making them unsuitable for metrology. Therefore, the most promising route to generate fully-spatially-coherent VUV sources is to up convert light from the visible-infrared region of the spectrum, where coherent laser sources already exist. However, a significant technical obstacle towards this goal is the lack of reliable solid-state nonlinear-optical crystals that work in the deep-UV. Unavoidable residual absorption at wavelengths 200nm can lead to long-term damage of nonlinear optical crystals, requiring constant replacement. Furthermore, for frequencies 193nm, no suitable nonlinear optical crystal currently exists. Therefore, gaseous nonlinear-optical media are an attractive alternative to crystals for generating light at wavelengths 200nm. This SBIR Phase II project will use four-wave mixing in gas filled hollow waveguides to develop a tabletop VUV laser capable of generating 10's of mW, and possibly 100's of mW of light at 157nm and at 193nm, in a fully coherent beam, at the very high (10kHz) repetition rates necessary for applications in metrology.This project has the potential to have a very broad impact on the semiconductor and electronics industries, as well as in basic science. Progress in both the complexity and the speed of microprocessors, DRAM memory, and other integrated electronics has been driven by the ability to make increasingly dense IC's, with ever-smaller feature sizes. This has been enabled by the development of higher-resolution lithographic "steppers" and the use of ever-shorter wavelengths of light for lithography. Because no bright, tabletop, sources currently exist, most short-wavelength materials, nano- and chemical science must take place at synchrotron sources, where access is limited and the sources are not optimized. Therefore, significant gains in productivity could occur with the availability of such a source.