This video presentation is about the 50th anniversary of Micralign: a retrospective.

Over the last 20 years, mobile devices have fundamentally changed the way we interact with the external world and with each. Augmented reality is the next obvious step to completely eliminate any barrier between us and our metaverse. Fundamentally, it will transform all aspects of our lives merging the real and virtual world. But much as smartphones 20 years ago, it requires multiple innovations in optics, photonics, sensors and silicon to be successful. In order to make this vision reality, we have been aggressively investing in NTIs across the areas. Today, I will speak about some of the progress in terms of display, photonics and tracking technologies.

To enable further cost-effective scaling of technology nodes, the next generation EUV platform has been developed with an increase of the numerical aperture (NA) from 0.33NA to 0.55NA. This next generation EUV platform is called High NA and is an evolutionary step for EUV technology. High NA EUV will bring multiple benefits to the semiconductor market such as reduction of process complexity, yield improvement, higher resolution enabling printability of smaller features at increased density, and cost of technology reduction. The development of High NA is done in several phases. First we develop and qualify High NA modules. Next we build subsystems that can be independently pre-qualified. And finally we will build those pre-qualified subsystems into High NA scanner systems that will be shipped to customers.

In recent years the promise of EUV lithography became a high-volume-manufacturing reality and is currently the main enabler for the latest generations of chips we all know and use. To enable the future generations of chips, with smaller feature sizes ZEISS and ASML are developing a new generation of EUV tools, with an increased NA from the current 0.33 to 0.55 allowing the lithographers to print 8nm half-pitch in a single exposure. In this presentation we will remind briefly on high-NA optics concepts as compared to its 0.33-NA predecessor. We will give insight into how advanced the current production status at ZEISS is: not only into mirror surface polishing, coating, metrology, but also mirror handling and integration as well as shipment. Moreover, besides what happens in high-NA program, you will also see the current status and ongoing improvements to 0.33-NA optics.

EUV interference lithography (EUV-IL) plays an essential role in developing photoresist materials for EUV lithography. Hitherto, the highest resolution has been achieved by diffraction gratings positioned on thin transparent membranes. Yet, these gratings are tied in with critical fabrication challenges when aiming towards the ultimate resolution at the sub-10 nm half-pitch regime. To this end, we present an EUV-IL setup based on light reflection upon two low-absorption mirrors. Combined with brilliant and coherent synchrotron light, this Lloyd’s mirror-inspired device delivers single-digit HP patterning with remarkable efficiency and throughput.

The AIMS® EUV system represents a unique piece of the EUV mask infrastructure for the qualification of the mask printing performance in the aerial image. To meet the industry requirements in the future, ZEISS started the development of a next generation EUV mask review tool, the AIMS® EUV 3.0. The system is based on the best-in-class optical concept proven for the current generation. The tool will support 0.33NA isomorphic and 0.55NA anamorphic imaging from the beginning. In this paper, we will introduce the concept of the AIMS® EUV 3.0 and present the current development status.

With the coming adoption of EUV phase shift absorbers in high-volume manufacturing, it soon will be critical to ensure phase uniformity across the mask and stability over time. Synchrotron-based EUV variable angle spectroscopic reflectometry has been demonstrated to be a highly sensitive metrology technique for the measurement of phase. More recently, this phase measurement technique has been successfully implemented as a fab-scale tool based on a laser produced plasma source. The metrology enabled by this tool supports the continual monitoring of phase stability in a manufacturing environment, which can provide invaluable knowledge about best practices for mitigating or reversing phase drift resulting from effects such as contamination and mask aging. In this presentation we report on such phase drift measurements on real EUV masks looking at various sources of phase change on the mask.

Photolithography equipment is the enabler of semiconductor device development. While i-line and DUV equipment replaces Mask Aligners to satisfy the overall miniaturization of More-than-Moore components (Power, RF, MEMS..), Advanced Packaging (AP) elaboration is tormented by multitude of challenges. Indeed, packaging is the limitation to performance of components manufactured with EUV lithography. Hence, AP architectures are flourishing, for which Laser Direct Imaging as well as i-line and DUV patterning are used. In this exciting time, we study photolithography equipment market, ecosystem and technology trends looking in detail into the forecast, market share, supply chain and auxiliary to patterning processes and equipment.

25 years ago, Fraunhofer IOF started the very first project on EUV multilayer development. This paper summarizes highlights of this exciting journey from the first still low reflecting multilayer coating made in 1998 to today’s 15 million € investment in optiX fab’s EUV optics fab.

With EUV Lithography being in production for a couple of years the lithography optimization focuses on two main aspects: improving the productivity (e.g. by lowering the dose to size) and reducing the smallest pitch in the design. This has led to a reassessment of the applicability of contrast/resolution enhancement techniques. Another very important aspect, impacted by dose to size and minimum pitch, is the variability in the lithography which needs to be reduced over time in line with the EPE requirements of the device manufacturing. We will restrict ourselves on the items which can be observed after exposing on a single scanner and for simple test structures (single layer EPE), thus omitting variability from layer to layer overlay, proximity bias differences between scanners, OPC errors through features and etch effects. It includes global and local CD errors, and global and local placement errors of the structures.

The Edge-placement-error requirements keep progressively scaling down in immersion lithography process in conjunction with Immersion lightsource technology. We studied quantification analysis of impact on resist LWR/ LER to the speckle dependency by; a. LWR/LER by analyzing the Power Spectral Density (PSD) curves. b. key frequency components by the photo resist and/ or the speckle contrast such based on PSD tendency by # of pulse use during exposure c. further speckle contrast reduction for LWR/ LER enhancement by 4X extension of Pulse duration.

At present 250W power level is realized in semiconductor mass production factories1) by ASML. On the other hand, pioneer of this Unique technologies including; combination of pulsed CO2 laser and Sn droplets, dual wavelength pico second laser pulses for shooting and debris mitigation by magnetic field have been applied by Gigaphoton2). They have demonstrated high average power >300W EUV power with CO2 laser more than 27kW at output power in cooperation with Gigaphoton and Mitsubishi Electric3). In near future more higher power (>800W) EUV source is required to fit High NA (>0.55) lithography of semiconductor industry. In this paper we will discuss about the Sn plasma dynamics which dominate the EUV emission by using Tomson scattering (TS) measurement4）. Recent TS results have revealed whole profiles of electron temperature and ion density in the EUV sources. These results mention that there is still sufficient potential to increase EUV output in the future.

The most critical enabler of actinic patterned mask inspection technology/capability has been the EUV source. In this paper, we discuss the performance and reliability improvements achieved for the LDP EUV Source (Laser-assisted Discharge Produced Plasma EUV Source) used in Intel actinic patterned-mask inspection systems. These improvements encompass several critical aspects such as EUV emission conversion efficiency, source lifetime and debris mitigation effectiveness. Optimization of the parameters that influence LDP discharge has enabled improvement to these performance indicators. Duration of continuous operation of the source has been extended by novel modification of the electrode design as well as other changes. Ion induced damage to the optical components such as downstream mirrors was mitigated by development of an effective debris mitigation approach. These improvements have significantly increased the duration of uninterrupted operation, EUV brightness level, as well as improvements in plasma stability.

EUV pellicle has been actively researched as a solution for defect mitigation of EUV mask. Its EUV reflectance (EUVR) less than 0.04% is strictly required to prevent critical dimension drop (ΔCD). But high-power EUV in the scanner can induce the occurrence of wrinkles on the pellicle and it can affect the optical properties of pellicle like EUVR. In this study, we experimentally investigated the change of EUVR induced by the pellicle wrinkles and its effects on mask imaging performance with EUV ptychography microscope, an actinic inspection tool using coherent EUV light source from high harmonic generation. As a result, we confirmed not only a local increase of EUVR (approximately 4 times) but also randomly changed beam path of the reflected light by the wrinkle. To confirm the effect of those reflected light from the wrinkle on mask imaging performance, we reconstructed the aerial images using a ptychographic algorithm after synthesizing the reflected EUV light into a contact hole mask diffraction pattern. As the aerial image is obtained by superposing the diffracted light, the mask imaging performance can be variated by synthesized EUV light. The reflected light near 1st order diffraction pattern affects CD resulting from its spatial frequency, whereas the reflected light near 0th order diffraction pattern works as noise causing contrast loss. Eventually, ΔCD as large as 6 nm was observed. Therefore, even if the pellicle satisfies the EUVR requirement, we need to tightly control the generation of wrinkles to suppress CD variation during the exposure process.

EUV emission spectrum from Sn and rare-earth plasmas exhibits complex structure. We study the numerical model of the plasmas to reproduce the emission for the optimization of the sources. We investigate the atomic structure of Sn and rare-earth ions. We investigate the population to the multiply excited states to determine the ionization balance. We also investigate the properties of emission lines to improvement of the accuracy of the calculation. Wavelength and width of UTA (Unresolved Transition Array), which contributes to the EUV emission, are investigated by comparing calculated and experimental spectrum. Emission from multiply excited state, that may cause broadening of the UTA at high densities, is also investigated.

The global semiconductor market is expanding, and while equipment that maximizes availability is required to manufacture a large number of semiconductors, equipment with low electric power consumption and high productivity is required to realize a sustainable society. The new ArF lightsources developed by Gigaphoton reduce the number of replacement parts required by extending the replacement interval for consumable parts by 20%. The new KrF lightsources reduce the electric power required to produce a wafer by 20%. These have contributed to maximized availability and sustainability.

As the EUV pellicle becomes more widely applied in the semiconductor industry, efforts are carried out to develop an EUV pellicle with a transmittance of over 90% and a heat emission efficiency that can withstand the increasing EUV source power. A metal silicide applied to such a pellicle can form crystal structures exhibiting different thermal properties depending on it. In this paper, the rapid thermal annealing process was performed to crystallize the MoSi₂ pellicle composite and subsequent thermal property evaluation confirmed the change in heat emission efficiency depending on the crystal structure. On the SiNx membrane fabricated through KOH wet etching, MoSi₂ and SiNx were deposited through co-sputtering and reactive sputtering, respectively. The composite films were annealed at various temperatures and time conditions through a rapid thermal annealing process. The crystallinity and resistivity of the films were analyzed using XRD and 4-point probe. Heat load tester was introduced to evaluate heat emission efficiency. The temperature of the pellicle surface was measured by optical pyrometer under 808 nm laser irradiation conditions, emulating the EUV exposure process. It was confirmed that the hexagonal and tetragonal structures of MoSi₂ were formed in the pellicle according to the annealing temperature. Structural change due to the heat treatment alters the band structure, which leads to a change in free-electron density. According to the Drude model, these variations in free electron density can affect the thermal emissivity of nano-membrane structures. For the heat load test, the tetragonal structured MoSi₂ pellicle with low resistivity reached lower temperature at the same thermal load, thereby confirming the higher heat emission efficiency compared to that of the hexagonal structure.

Extreme ultraviolet (EUV) lithography sources use large amounts of tin to create ultraviolet light. Accurate modeling of neutral tin transport relies on knowledge of the diffusion coefficients of neutral tin through molecular hydrogen. This work experimentally determined the diffusion coefficients of tin through molecular hydrogen at different tin temperatures and ambient pressures. A known amount of tin is evaporated into a pipe with a known flow profile at a known ambient pressure. Deposited tin is measured down stream of the pipe with a quartz-crystal microbalance (QCM). A variety of analytical and numerical coefficients were then compared in order to find the diffusion coefficient.