The development of laser-produced plasma EUV light source

Spectral purity systems applied for laser-produced plasma extreme ultraviolet lithography sources: a review

“…At present, the collector is generally deposited with Mo/Si multilayers to achieve high EUV reflectivity [ 11 ] . Figure 3 shows the reflectivity of Mo/Si multilayers to different radiations.…”

“…As one of the most important sub-modules, the collector is a multilayer-coated mirror that is in the shape of the graded ellipsoid with 5.5 sr [ 7 , 11 , 12 ] . With it, the EUV radiation generated can be collected and concentrated to the IF, as shown in Figure 2.…”

“…With it, the EUV radiation generated can be collected and concentrated to the IF, as shown in Figure 2. In order to satisfy the actual production requirements of EUV radiation with high efficiency, high power and high purity, the collector needs to meet some design specifications [ 8 ] , such as having a large enough solid collecting angle of 5.5 sr [ 7 , 11 , 12 ] and a highly reflective multilayer coating, as well as some specific designs to reduce the thermal load of the collector, such as a water-cooling device. However, a collector meeting the above requirements at the same time can also transmit out-of-band (OoB) radiations, that is, radiations other than 13.5 nm (2% band) EUV radiation.…”

A study of hydrogen plasma-induced charging effect in EUV lithography systems

“…The first low-intensity pulse flattens the Sn droplet into a pancake shape. The second high-intensity laser pulse vaporizes the Sn droplet to generate a plasma that emits EUV light [5]. During the de-excitation of the Sn plasma, some Sn atoms may accumulate on the incidence mirrors within the chamber, reducing their reflectivity.…”

Piezoelectric High Temperature Liquid Droplet Spraying Component

“…集成电路是当今信息社会的基石，也是人类工业文明的集大成者。而用于制备芯片的光刻技术则是 集成电路领域的核心技术。为满足人工智能、云计算、大数据等领域对处理器越来越高的算力需求，芯 片制程不断下探，从 28 nm 到 14 nm，再到全面迈向 7 nm 及以下节点 [1][2][3] 。在芯片制造过程中，制程尺 寸越小，制造精度就越高，传统的深紫外(λ = 193 nm)光刻技术已经无法满足这些要求。EUV 光刻使用波 长更短、能量更高的 EUV 光(λ = 13.5 nm)作为曝光光源，可以实现更高的分辨率和更小的制程尺寸。因 此，EUV 光刻已成为实现更小制程节点的首选技术 [4][5] 。 EUV 光源是 EUV 光刻系统中重要的组成部分，高功率、稳定的光源为整体系统的稳定工作奠定基 础。EUV 光源主要通过放电等离子体和激光等离子体获得，其中激光等离子体 EUV 光源由于其功率可 拓展、极紫外辐射收集效率高等特性，是当前量产光刻机用高功率 EUV 光源的解决方案之一 [6][7] 。激光 等离子体采用高功率短脉冲激光轰击锡液滴流靶，产生等离子体以辐射 EUV 光。均匀、稳定、小尺寸的 高频锡液滴靶是获取高质量 EUV 光源的关键 [7][8] 。 基于逆压电效应的压电式高温液滴喷射元件是获取高质量锡液滴靶的首选方案，其核心功能元件耐 高温微细压电陶瓷管的典型特点是耐高温(＞240 ℃)、高性能(压电系数 d33＞350 pC/N)、大长径比(长径 比＞20)和薄壁(0.2~0.8 mm)。其中，微细压电陶瓷管的精细制备是关键技术难点。中国科学院上海硅酸 盐研究所压电陶瓷材料与器件研究团队基于自主研制的 PZT 高温压电陶瓷材料，突破了微细压电陶瓷管 的成型、烧结、加工、极化、性能测试等一系列核心技术，成功研制出耐 250 ℃高温的微细压电陶瓷管， 同心度、线性度等均达到了国外同类产品水平，分别如图 1(a, b)所示。基于射流断裂原理 [9] ，通过电压驱 动微细压电陶瓷管产生的径向振动对射流产生周期性扰动，形成了均匀、稳定的锡液滴靶。 在此基础上，联合中国科学院上海光学精密研究所 EUV 光源团队，解决了压电式高温锡液滴喷射元 件的密封组装与高温真空气密性等关键问题，实现了压电式高温锡液滴喷射元件的自主制备，如图…”