加速器極紫外光源發展概況

An Overview of Accelerator-based EUV Sources

劉偉強(Wai-Keung Lau)；劉宗凱(Zong-Kai Liu)；羅皓文(Hao-Wen Luo)

科儀新知

240期（2024 / 09 / 30）

77 - 91

繁體中文;英文

近年來，半導體產業在大量生產技術上取得了顯著進步，其中穩定可靠的極紫外光微影製程（EUVL）技術功不可沒。目前，商用EUVL系統中所使用的光源主要是利用二氧化碳雷射驅動錫電漿（LPP）產生13.5奈米波長的極紫外光，雖然其在滿足晶片量產需求上發揮了重要作用，但同時也面臨著如鏡片污染等技術挑戰。為進一步提升EUVL製程速度，增加光源功率是其中一個重要的方向。本文介紹了加速器光源技術的發展現況並討論在EUVL中的應用潛力。加速器光源，特別是同步輻射和自由電子雷射（FEL）隨著光子科學的興起而受到重視。同步輻射是高能電子在磁場中運動時發出的電磁輻射，具有寬頻帶、高亮度和高準直性等特點，已成為許多科學研究領域的重要光源。FEL則利用電子束在聚頻磁鐵中與電磁場的交互作用產生高強度同調輻射，具備更高的輻射功率和無污染的優勢。FEL的實現需要一系列關鍵技術，包括低發射度電子源、磁力束團壓縮器和微波直線加速器等。這些技術的發展為FEL提供了高亮度相對論性電子束，成為實現高功率EUV光源的基礎。半導體產業對高功率EUV光源需求的增加，也使得它們在EUV波段的應用受到許多關注。本文從同步輻射及FEL的基本原理到技術實現進行了討論，並探討了能量回復直線加速器（ERL）和穩態微聚束（SSMB）技術在發展高功率EUV光源的前景。

In recent years, the semiconductor industry has achieved significant advancements in high-volume manufacturing, largely due to the stable and reliable implementation of extreme ultraviolet lithography (EUVL) technology. Current commercial EUVL systems primarily utilize laser-driven plasma (LPP) sources with a 13.5-nanometer wavelength, which are crucial for meeting the demands of high-volume wafer production. However, these systems face technical challenges, such as the increasing demand of EUV radiation power and lens contamination. This article reviews the current state of accelerator-based light source technology and its potential applications in EUVL. Accelerator-based light sources, particularly synchrotron radiation and free electron lasers (FELs), have attracted significant interest with the rise of photon science. Synchrotron radiation, emitted by high-energy electrons in a magnetic field, is characterized by a wide frequency band, high brightness, and excellent collimation, making it a vital tool in various scientific research fields. FELs, which generate high-intensity coherent radiation through the interaction of electron beams with electromagnetic wave in undulator magnetic field, offer advantages such as higher radiation power and minimal contamination. The development of FELs requires several key technologies, including low-emittance electron sources, magnetic electron bunch compressors, and microwave linear accelerators. These technologies are critical for providing FELs with the high-brightness relativistic electron beams necessary to achieve high EUV power. As the semiconductor industry's demand for high-power EUV radiation sources grows, the application of accelerator-based technologies in the EUV spectrum has gained increasing attention. This article explores the principles of synchrotron radiation and FELs, delves into their technical implementations, and examines the potential of energy recovery linear accelerators (ERL) and steady-state micro-bunching (SSMB) technologies in the development of high-power EUV radiation sources.