[EUVL Part3]  EUV Mirror
Channel: SemiSlides
Date: 2023-11-17

*Welcome to our in-depth exploration of Extreme Ultraviolet Lithography (EUVL) for patterning on silicon wafers in semiconductor fabrication. Over the course of five episodes, we'll delve into every aspect of this revolutionary technology that is reshaping the modern lithography landscape. In this third episode, we explore the EUV mirrors that reflect EUV light from the source vessel to the resist on the wafer. Below are the main chapters of this video. Click on any timestamp to jump directly to the desired chapter.*

1. EUV Optics: Understanding the basic optics regarding EUV light behavior
[02:10] Absorption & Transmission Behavior of EUV Light: Explaining why reflective mirrors are necessary.
[05:00] Reflection Behavior of EUV Light: Less than 1% reflection in case of single-layer optics.
[07:40] EUV Mirror Types: Grazing-incidence (GI) mirrors & Artificial Bragg Reflectors.
[11:00] EUV Bragg Multi Layer Mirror (MLM): Features of MoSi MLM.
[15:30] How EUV Mirrors Narrow the EUV Bandwidth.
[19:20] EUV Out-of-band (OOB) Radiation: Its negative effects on imaging of CAR-type resist.

2. LPP Collector: Exploring the hemispherical EUV mirror in the EUV light source vessel
[23:50] LPP EUV Collector: Harvesting and transferring the power of EUV light to the intermediate focus (IF).
[27:05] Diffraction Grating for IR OOB Elimination: Eliminating IR light using a diffraction grating.
[29:45] Managing Tin Contamination: Addressing serious collector mirror contamination from accumulated Tin fuel.
[32:55] Hydrogen Buffer Gas Strategy: Reducing Tin contamination with Péclet Shielding and Reactive Cleaning.
[36:25] Why Hydrogen is a Good Choice for Buffer Gas.
[39:10] Management of Primary Tin Debris: Controlling hydrogen gas flow in the source vessel.
[42:25] Management of Secondary Tin Debris: Thermal cycling of tin debris on the vessel wall.
[46:20] Maximizing Collector Lifetime: Introducing advanced capping layers and hydrogen radical cleaning.
[49:25] Gigaphoton's Magnetic Collector: Reducing tin debris by trapping tin ions with a magnetic collector.
[51:50] ASML's Modular Vessel (MV) System: Reducing tool downtime for vessel cleaning service.

3. Illuminator Module (ILLUMO): Understanding illumination beam shaping to the reticle in the EUV system
[53:50] Zeiss' Starlith 3400 ILLUMO in NXE:3400 HVM Tool: Field Facet Mirror (FFM), Pupil Facet Mirror (PFM), and Grazing Incidence Mirror (GM).
[1:04:35] Curved Slit Field in EUV System: Explaining why a curved slit field (Ring Field) is used in contrast to a straight slit field in the ArF system.

4. Projection Optics Box (POB)
[1:08:00] Zeiss' Starlith 3400 POB in NXE:3400 HVM Tool: Featuring 6 aspherical mirrors.
[1:11:30] 6 Mirror Design for NA0.33 Projection Optics: Discussing the importance of Etendue.
[1:16:50] EUV Mirror Metrology: Quality parameters of mirror optics (Figure, MSFR, HSFR) and their measurement methods.
[1:20:15] Crafting Clarity: Extreme requirements for mirror roughness quality.
[1:26:25] Advancement of Mirror Quality: Demonstrating chronological improvements in mirror roughness.
[1:32:15] Low Temperature Expansion Material (LTEM): Substrate properties for EUV mirrors.
[1:36:50] Zeiss EUV Mirror: Mirror fabrication procedures and metrology at Zeiss.
[1:44:35] Protection of EUV Mirror from Contamination by Resist Outgassing: Dynamic Gas Lock (DGL) & DGL membrane.