Optical projection lithography using gradation stitching of the exposure fields

光学投影光学成像是制造先进半导体器件的关键技术之一。如果要购买高度集成的设备，那么芯片大小应该被放大。不管怎样，它将变得非常困难，以实现更大的曝光领域的更高分辨率。由于这个原因，一个独特的方法来缝合小暴露场平滑和真实地显示大型芯片暴露在本研究中被调查。在新的方法中，扫描暴露是有效的，每个领域都是用强度分级来暴露的。邻里的田野一侧的分级是有控制的，使初始的田野被缝合。因此，在被缝合的部分中的总强度保持不变，并等于在被缝合的部分中的一个。这种分级缝合暴露的有效性是用实验室-建造的暴露系统来证明的。在调查方便切片形状后，采用80度的光滑切片与一个表面角度。作为我的第一个实验 ... More “暴露出缝合部件的均匀性和连续性在跟踪平面上被评估，以使打印出图案的投影光学的复杂影响在芯片上。”暴露和开发对一个特殊的抵抗者，在开发后，暴露剂量的变化几乎是线性的，可以用来检测狭窄的零件中的局部不规则剂量的分布。它是明确的，因为缝合部分中的剂量不质量已经成功地通过采用新的方法得到了改善。更进一步，它证明了顶视图概况和线条宽度的变化也是相当小和不利的。在第二阶段，扫描投影暴露的模式缝合是被调查的。这是一个证明，如果被缝合的零件中的模式甚至不退化，即使场地也会被缝合而成的位置上的固有错误。“缝合位置的误差幅度将变得非常大。”它将成为一种巨大的高分辨率投影光学。有一个大的领域，一个短波浪在后面。应用分级缝合暴露，较大的LSI芯片将被缝合两个小扫描场复制得最好。如果一个小的场地大小是可以接受的，分辨率和/或焦点的深度也可以被明显地改善。Less（低）

Optical projection lithography is one of the key technologies for fabricating advanced semiconductor devices. In order to obtaining highly integrated devices, chip sizes should be enlarged. However, it becomes very difficult to realize higher resolution for a larger exposure field. For this reason, a unique method for stitching small exposure fields smoothly and realizing large chip exposure was investigated in this research. In the new method, scan exposure is utilized, and either side of the fields are exposed with intensity gradation. Gradation of the neighborhood field side is controlled inversely to the initial field to be stitched. Thus, the total intensity at the stitched parts is kept constant and equals to the one at the non-stitched parts. Effectiveness of this gradation stitching exposure is demonstrated using a laboratory-built exposure system. After investigating convenient slit shapes, trapezoidal slits with an apex angle of 80゜ were adopted. As the first experimental sta … More ge, exposure dose uniformity and continuity of the stitched parts are evaluated at the reticle plane in order to eliminate the complicated influence of the projection optics on patterns printed on wafers. Exposure and development of a special resist the dissolved depth of which after development changes almost linearly with the exposure dose is utilized for detecting partial irregular dose distribution in the narrow stitched parts. It is clarified that the dose inequality in the stitched parts is successfully improved by adopting the new method. Moreover, it is proved that the changes of top-view profiles and line widths are also very small and negligible. As the second stage, pattern stitching for scan projection exposure is investigated. It is demonstrated that patterns in the stitched parts don't degrade even if the fields are stitched with certain intentional errors of positions. Error margin of the stitching positions becomes very large. It will become difficult to develop a high-resolution projection optics. with a large field for shorter wavelengths hereafter. Applying the gradation stitching exposure, large LSI chips will be replicated favorably by stitching two small scan fields. If a small field size is admissible, resolution and/or depth of focus will also be considerably improved. Less