EUV 光刻为何必须放弃透射式投影物镜、改用 Mo/Si 多层膜反射系统?13.5 nm 光源又为何选激光激发锡等离子体?
Why does EUV lithography have to give up transmission projection lenses for reflective Mo/Si multilayer optics, and why is a laser-produced tin plasma used as the 13.5 nm source?
几乎所有材料对 13.5 nm 极紫外光吸收极强且折射率实部趋近于 1,不存在任何厚度的可用透镜,只能依靠单层约 7 nm 的 Mo/Si 交替膜通过布拉格反射实现约 70% 的峰值反射率。常规增益介质没有极紫外波段的跃迁,故以 CO2 激光轰击约 25 μm 锡液滴产生高温等离子体,其高价锡离子的密集谱线恰好叠加出 13.5 nm 附近的有效辐射。这决定了 EUV 光路全程真空运行、反射镜面形与多层膜周期误差须压至皮米级,也带来收集效率低、功率链损耗大的工程代价。
Essentially all materials absorb 13.5 nm light extremely strongly with refractive-index real parts near unity, so no usable lens exists at any thickness; reflective optics rely on Mo/Si bilayer stacks roughly 7 nm per period acting as Bragg mirrors with peak reflectivity around 70 percent. Ordinary gain media offer no transitions at extreme-ultraviolet wavelengths, so a CO2 laser vaporizes tin droplets about 25 micrometers wide, and dense emission lines of highly charged tin ions combine into useful radiation near 13.5 nm. This physics forces an all-vacuum beam path, picometer-level control of mirror figures and multilayer periods, and the well-known penalties in collection efficiency and source power.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-10-04
来源 · Source
Wu B, Kumar A. Extreme ultraviolet lithography: A review[J]. Journal of Vacuum Science & Technology B, 2007, 25(6): 1743-1761.
B. Wu and A. Kumar, 'Extreme ultraviolet lithography: A review', Journal of Vacuum Science & Technology B, vol. 25, no. 6, pp. 1743-1761, 2007.
独立核验依据 · Independent verification: 核验依据 1 DOI 10.1036/1097-8542.yb040505
#EUV光刻 #多层膜反射镜
在CMOS晶圆制造中,为什么化学机械抛光(CMP)是实现多层互连的关键工序?
In CMOS wafer fabrication, why is chemical mechanical planarization (CMP) a critical step for building multilevel interconnects?
随着金属层数增加,晶圆表面起伏不断累积,光刻景深无法容忍这种高度差。CMP同时利用化学腐蚀与机械磨削去除多余介质和金属,把表面恢复到纳米级平整。只有在此基础上,上层光刻才能完成亚微米图形的精确转印。
As metal layers stack up, wafer topography accumulates until it exceeds the depth of focus of lithography. CMP removes excess dielectric and metal through combined chemical etching and mechanical abrasion, restoring nanometer-scale flatness. Only on such a planar surface can the next lithography layer transfer submicron patterns accurately.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 来源待核验 · Source pending review
来源 · Source
出处备注：著录仅给书名，无版次与年份；同一书名常对应多个版次，不臆测具体版本。
Peter Van Zant,《芯片制造:半导体工艺制程实用教程》(Microchip Fabrication),第7版,CMP章节
Peter Van Zant, Microchip Fabrication: A Practical Guide to Semiconductor Processing, 7th ed., CMP chapter
独立核验依据 · Independent verification: 核验依据 1 ISBN 9787121243363（豆瓣书目条目） · 核验依据 3 ARCHIVE 标识 microchipfabrica0002vanz：Microchip fabricatio
#半导体工艺 #化学机械抛光
为什么化学机械抛光(CMP)要同时使用磨料颗粒和氧化性化学液,二者各自承担什么作用?
Why does chemical mechanical planarization (CMP) use both abrasive slurry and oxidative chemistry, and what role does each play?
化学组分先在凸起处氧化生成一层软质反应层(如钨表面生成WO3、铜表面生成钝化膜),机械磨粒随后以微米级压力把这层软膜优先去除。单独化学腐蚀会各向同性地侵蚀并损伤介电层,单独机械研磨则会划伤且无法达到原子级平坦。两者耦合实现了凸凹选择性去除,这是多层互连大马士革工艺实现全片平坦化的关键。
The chemistry first oxidizes high spots into a soft reaction layer (such as WO3 on tungsten or a passive film on copper), and abrasive particles under micron-scale pressure then preferentially remove that softened layer. Chemistry alone attacks isotropically and corrodes the dielectric, while mechanical grinding alone scratches the surface and cannot reach atomic-level flatness. Coupling the two gives selective removal of highs over lows, which is what enables full-wafer planarization in multilevel damascene interconnect processing.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 来源待核验 · Source pending review
来源 · Source
出处备注：此条未指向带版次的可引用著作（通识性内容、机构文件或未展开的英文书名），本库不提供独立书目出处；如需精确引用，需由编辑补全具体篇目与版次。
Krishnan et al., MRS Bulletin, 2010, 35(7): 506-513 / Oliveros et al., Tribology International, 2024, 191: 109150
Krishnan et al., MRS Bulletin, 2010, 35(7): 506-513; Oliveros et al., Tribology International, 2024, 191: 109150
#化学机械抛光 #平坦化工艺