High-precision alignment system for DMD-based maskless lithography in multilayer exposure applications

IF 3.7 2区 工程技术 Q2 ENGINEERING, MANUFACTURING
Ting Hsuan Miau , Chun Ying Wu , Yung Chun Lee
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引用次数: 0

Abstract

Maskless lithography based on Digital Micromirror Devices (DMDs) has advanced rapidly in recent decades and offers a flexible and efficient alternative to conventional lithography methods that require physical photomasks. In many applications, multilayer exposure and patterning of photoresist (PR) layers are common, essential, and required for most lithography systems. Consequently, effective methods are needed to ensure accurate layer-by-layer alignment of the successive exposure patterns. However, despite the importance of alignment, current DMD-based maskless lithography systems lack methods to achieve high-precision alignment across multiple layers. Accordingly, this study proposes a simple yet effective alignment system for DMD-based maskless lithography incorporating a downward image sensor and an upward image sensor. The downward image sensor captures the alignment targets on the substrate or previous layer, and the coordinates of these targets are determined using digital image analysis techniques. The upward-facing sensor simultaneously measures the offset distance between the optical engine and the downward-facing sensor. Given the information acquired from the two sensors, the current posture of the substrate relative to the DMD can be accurately determined and the planned exposure coordinates for the subsequent layer corrected as needed. The experimental results show that the proposed method achieves an average alignment accuracy of 1.76μm in the x-direction and 0.63μm in the y-direction, with a maximum error of 3μm. This level of precision meets the alignment requirements for circuit board exposure. Alignment exposure tests conducted on commercial substrates confirm the applicability of the proposed alignment system for real-world lithography.
多层曝光中基于dmd的无掩模光刻高精度对准系统
近几十年来,基于数字微镜器件(dmd)的无掩模光刻技术发展迅速,为需要物理掩模的传统光刻方法提供了一种灵活高效的替代方案。在许多应用中,光刻胶(PR)层的多层曝光和图像化是常见的,必不可少的,并且是大多数光刻系统所必需的。因此,需要有效的方法来确保连续曝光模式的准确逐层对齐。然而,尽管对准很重要,目前基于dmd的无掩模光刻系统缺乏实现多层高精度对准的方法。因此,本研究提出了一种简单而有效的基于dmd的无掩模光刻对准系统,该系统包含一个向下的图像传感器和一个向上的图像传感器。向下的图像传感器捕获基板或前一层上的对准目标,并使用数字图像分析技术确定这些目标的坐标。向上传感器同时测量光引擎与向下传感器之间的偏移距离。根据从两个传感器获取的信息,可以准确地确定衬底相对于DMD的当前姿态,并根据需要校正后续层的计划曝光坐标。实验结果表明,该方法在x方向和y方向上的平均对准精度分别为1.76μm和0.63μm,最大误差为3μm。这种精度水平满足电路板曝光的对准要求。在商业基板上进行的对准曝光测试证实了所提出的对准系统在实际光刻中的适用性。
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来源期刊
CiteScore
7.40
自引率
5.60%
发文量
177
审稿时长
46 days
期刊介绍: Precision Engineering - Journal of the International Societies for Precision Engineering and Nanotechnology is devoted to the multidisciplinary study and practice of high accuracy engineering, metrology, and manufacturing. The journal takes an integrated approach to all subjects related to research, design, manufacture, performance validation, and application of high precision machines, instruments, and components, including fundamental and applied research and development in manufacturing processes, fabrication technology, and advanced measurement science. The scope includes precision-engineered systems and supporting metrology over the full range of length scales, from atom-based nanotechnology and advanced lithographic technology to large-scale systems, including optical and radio telescopes and macrometrology.
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