This thesis introduces a new class of interferometric pattern and probe-based aberration monitors based upon the principle of coherent electromagnetic spillover among transmitting phase-shifting regions and assesses their implementation on the currently installed base of photolithographic exposure tools. The mathematical theory developed is based upon the diffraction integral for coherent imaging and shows that the optimum patterns for measuring aberrations are the two-dimensional inverse Fourier transforms of the original aberration functions, expressed as Zernike polynomials. As a result, each aberration monitoring target consists of a sub-resolution probe surrounded by a number of pattern rings which are near the resolution limit of the exposure tool. The positions and phasing of the rings are determined by the original aberration function. The rings act to spill electric-field over onto the central probe position in an amount which varies linearly with the amount of the given aberration.; Through simulation the monitors show an intensity response at the central probe position of 20 to 30% of the clear field per 0.01 l rms of aberration. This is over 50x stronger than the Strehl ratio response. Using the defocus target, it has been possible to measure the defocus aberration down to 0.01 l rms. Simulation results also show that the targets are, at most, 1/6 as sensitive to other, similar aberrations that they are not designed to detect.; The targets were fabricated in multi-phase masks for a maximum numerical aperture of 0.80 and wavelengths of 248 nm and 193 nm, and their experimental performance has been characterize using AIMS and photoresist exposures. In practice, the performance of the targets is limited by a number of second order effects. Analysis shows that misalignment, biasing, and phase etch error all affect the defocus target to less than 5% in electric-field. The most influential factor is the impact of the illumination partial coherence, as it weights the spillover fields from the ring elements differently depending upon their radii. While this causes a 28% change in the electric-field for sigma = 0.30, the effect can be reduced to less than 4% by lowering sigma to 0.15. The second most important effect is that of the electromagnetic mask transmission for etched features, which reduces the field from the probe by 20%. This effect can be eliminated however by biasing the feature edges by 0.044 lNA . Finally, while it does not impact the probes, high-numerical aperture polarization effects at NA = 0.80 change the desired aerial image fields from the rings by 20%. This is reduced to less than 6% however when the image is transferred into photoresist.
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机译：本文基于相干电磁波在传输相移区之间的相干原理，介绍了一类新型的干涉图样和基于探头的像差监测器，并根据目前安装的光刻曝光工具对它们的实现进行了评估。建立的数学理论基于相干成像的衍射积分，表明测量像差的最佳模式是原始像差函数的二维傅立叶逆变换，表示为Zernike多项式。结果，每个像差监视目标都由一个亚分辨率探测器组成，该亚分辨率探测器被多个图案环包围，这些图案环接近曝光工具的分辨率极限。环的位置和相位由原始像差函数确定。环的作用是将电场溢出到探头中心位置，该电场量随给定像差的大小线性变化。通过模拟，监视器显示每0.01 l rms像差，在中央探头位置的20％至30％的透明场的强度响应。这比Strehl比率响应强50倍以上。使用散焦目标，可以测量低至0.01 l rms的散焦像差。仿真结果还表明，目标对其他并非旨在检测的类似像差的敏感度至多为1/6。在多相掩模中制造靶，最大孔径为0.80，波长为248 nm和193 nm，其实验性能已通过AIMS和光致抗蚀剂曝光进行了表征。实际上，目标的性能受到许多二阶效应的限制。分析表明，未对准，偏置和相位蚀刻误差都将散焦目标的电场影响降低到5％以下。影响最大的因素是照明部分相干性的影响，因为它会根据环形元素的半径对环形元素的溢出场加权不同。虽然这会导致sigma = 0.30时电场发生28％的变化，但可以通过将sigma降低到0.15来将影响减小到小于4％。第二个最重要的影响是蚀刻特征的电磁掩膜传输，将来自探头的磁场减小20％。但是，可以通过将特征边缘偏置0.044 lNA来消除此影响。最后，虽然它不影响探针，但NA = 0.80时的高数值孔径偏振效应会将来自环的所需航空像场改变了20％。但是，当图像被转移到光刻胶中时，该比例降低到小于6％。
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