EUV Micro-Exposure Tool (MET) for Near-Term Development Using a High NA Projection System

Size: px

Start display at page:

Download "EUV Micro-Exposure Tool (MET) for Near-Term Development Using a High NA Projection System"

Lynne Jordan
6 years ago
Views:

1 EUV Micro-Exposure Tool (MET) for Near-Term Development Using a High NA Projection System John S. Taylor, Donald Sweeney, Russell Hudyma Layton Hale, Todd Decker Lawrence Livermore National Laboratory Glenn Kubiak, William Sweatt Sandia National Laboratories Neil Wester International SEMATECH International SEMATECH 2nd International Workshop on EUV Lithography Burlingame, California October 17-19, 2000

2 The Micro-Exposure Tool (MET) provides early learning with a high-na imaging system x Microstepper 0.1 NA, small-field Engineering Test Stand 0.1 NA, full-field Key early results: Micro-Exposure Tool Resist Development 0.30 NA, small-field Defect Printability nm imaging Process Latitude Beta-Tools 0.25 NA, full-field Production Tools 0.25 NA, full-field

3 Optical layout of MET camera with condenser concept Mask C1 475 mm Illumination Condenser (C2 & C3) M2 M1 Wafer Discharge Source Micro-Exposure Tool (MET) Optical System 5x reduction NA 0.30 (20 nm resolution) 600 µm x 200 µm field with tilted conjugate planes Residual WFE 0.42 nm rms Aspheric departure M1: 3.8 µm M2: 5.6 µm Obscuration: 10% Baffles (not shown) prevent direct light transmission

4 MET provides ILS > nm -1 to 20 nm, providing capability beyond that of 0.1 NA 10x microstepper X MET Image Log Slope vs. Feature Width (LW/SW = 1) ILS (nm -1 ) ILS min = nm Feature Width (nm)

5 Superior contrast below 70 nm will support printable defect experiments and resist screening NA 10X Aerial Image Profile (Dense 50 nm L/S) MET Aerial Image Profile (50 nm Dense L/S) σ = NA MET σ = 0.7 Relative Intensity Relative Intensity Horizontal Position (nm) Horizontal Position (nm) Contrast ~ 0.34 Contrast ~ 0.81

6 Simulations predict that the MET has a DOF = 225 nm for 35 nm dense L/S ED Window Dense (NA 0.30, σ =.7, λ = 13.4 nm) Exposure delta (%) CD Process Window (Field 3, 35 nm dense) DOF = 225 nm (ELAT = ±5%) Linewidth 31.5 nm 38.5 nm Ideal See poster paper by Russ Hudyma on MET Process Modeling Focus (µm)

7 The High-NA MET enables EUV technology at the 70nm, 50nm, and 35nm nodes Resist development Printability of mask defects Line Edge Roughness EUVL extendability to 35 nm node Exposure-Defocus process window Experience with discharge source Development of focus system

8 Conceptual exposure tool

9 The Micro-Exposure Tool (MET) is envisioned as a flexible printing test-bed Imaging System (funded in FY99-00 by Int l SEMATECH) 0.30 NA (obsc.) 5x; 2 aspheric mirrors with Mo/Si coating Field size: 200 µm x 600 µm, non-scanning Stewart-truss PO Box with pico-motor actuation Source Discharge source Exposure Tool Compatible with 6-inch square format masks 200 mm wafers Focus system Visible light microscope for positioning Semi-automatic wafer and mask handling

10 Optional capabilities are under consideration Imaging System Non-tilted conjugate planes with low distortion in extended field Source Interchangeability with other sources with modified collection optics Rotating scan mirror to enable variable fill and nontilted conjugate planes Exposure Tool In situ alignment Micro-scanning configuration (with non-tilted planes) Fully-automated SMIF pod robotics

11 International SEMATECH is sponsoring the fabrication of the 0.3 NA MET projection optics The design for the aspheric 2-mirror camera is complete Carl Zeiss is manufacturing and testing the aspheric substrates Set 1 substrates will be delivered in Q Set 2 will be delivered in Q Set 1 Specs Set 2 Specs figure: 0.33 nm rms MSFR: 0.35 nm rms HSFR: 0.40 nm rms Figure metrology will be validated at LLNL using PSDI LLNL will ML-coat two sets of optics figure: 0.25 nm rms MSFR: 0.20 nm rms HSFR: 0.10 nm rms Two PO Boxes have been designed and built at LLNL Zeiss will perform system alignment using visible light interferometry PO Box 1 will be shipped to the US; PO Box 2 remains at Zeiss

Oblate Spheroid Peak departure: 3.82 µm Peak slope: -1.

12 Carl Zeiss MET primary data demonstrates aspheric convergence to Set 1 requirements MET Primary In-Process Measurements Type: Oblate Spheroid Peak departure: 3.82 µm Peak slope: µm/mm Figure f spatial 1 mm nm rms Metrology Reproducibility 0.056nm rms

13 The PO Box provides rigid support for the optics, an interface to the system, and alignment control M2 cell interface provides 360 clocking M2 Mounting button Exact-constraint bi-pod Precision balls for mounting and metrology Super Invar support ring M1 cell articulates in 6 degrees of freedom Variable-length strut (6 total) Picomotor actuation M1

14 The MET PO Box is ready for installation of optics Bi-pods Support ring Variable-length struts Display stand Shown with surrogate optics

Rolling-element bearings minimize non-repeatability due to friction Reproducibility

15 Common kinematic constraints enable the use of different mounts for metrology and installation M1 Metrology Mount Common Constraint Point M1 PO Box Mount Rolling-element bearings minimize non-repeatability due to friction Reproducibility of Zeiss figure measurements in this mount is nm rms M1 metrology mount with Al surrogate

16 Strut arm length has sensitive control using pivot flexure design See Layton Hale s Poster Paper Piezo-screw actuator 1. Actuation Actuation leads to shortening of the strut Pivot flexure LVDT Super Invar 2. Contraction (10:1 de-amplification) Pivot flexures

17 A key challenge is to identify a plan that supports high-na EUV exposures in 2 years Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Build projection optics Condenser design Project plan & specs In process Start Q4-00 Start Q4-00 Identify industrial partners Sub-system fabrication Integration First exposures

18 Conclusions A proposal for a High-NA EUV Micro-Exposure Tool (MET) has been endorsed by the I-SEMATECH Project Advisory Group (PAG) to provide early learning in resist development and defect printability I-SEMATECH has funded the construction of 0.3 NA projection optics suitable for the MET System planning is underway to assess specifications, schedule, and cost Potential industrial partners are invited to participate in system planning This work was performed under the auspices of the U.S. Department of Energy by University of California Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48. Funding was provided by the Extreme Ultraviolet Limited Liability Corporation under a Cooperative Research and Development Agreement. The authors also wish to acknowledge support from International Sematech through project Lith 112.

Optics for EUV Lithography

Optics for EUV Lithography Dr. Sascha Migura, Carl Zeiss SMT GmbH, Oberkochen, Germany 2018 EUVL Workshop June 13 th, 2018 Berkeley, CA, USA The resolution of the optical system determines the minimum