R. Lebert 1, K. Bergmann 2, O. Rosier 3, W. Neff 2, R. Poprawe 2

Transcription

1 R. Lebert 1, K. Bergmann 2, O. Rosier 3, W. Neff 2, R. Poprawe 2 1 AIXUV GmbH, Steinbachstrasse 15, D Aachen, Germany 2 Fraunhofer Institut für Lasertechnik 3 Lehrstuhl für Lasertechnik, RWTH Aachen

2 Abstract AIXUV is commercializing a compact, versatile gas discharge based EUV-source. This source is a unique solution to have local access to an EUV source at customer's laboratories. The lamp will be shipped for direct use (wall plugged) and is extremely simple to operate due to push button and closed loop control. The source is designed for lower operation costs and has lower investment costs than laser produced sources. The discharge principle offers long time stability. The use of gaseous "targets" offers high flexibility of the spectral characteristics. Line emitters such as oxygen, neon and Fluorine as well as broadband emitters (Xenon) are realized. A bunch of options is available to adapt the source to customer demands. Typical properties of the standard version using xenon are : about 50 mw/sr in 2 % bandwidth at 13 nm. More than 0.5 W/sr into the EUV range from 10 to 20 nm. Source diameter is mm. Accessible solid angle is up to π σρ. Minimum working distance for the application is about 10 cm. The repetition rate is 100 Hz (higher rates are under development). The Stability is better than 5% RMS pulse to pulse. Permanent operation is ensured with maintenance intervals of more than 100 Million pulses. AIXUV (pronounced: aex-u-v) is composed from : AIX represents AIX LA CHAPELLE which is the French name for the German town Aachen (other names: Aken, Aquis Grana, Aquis Grán) known as the town of Charlemagne (Carolus Magnus, Karl der Große) who was buried in the Cathedral of Aachen in 824. XUV is for extreme ultraviolet which is is the spectral range from about 1 nm to 50 nm. XUV includes special spectral sub-ranges known as soft x-rays and EUV.

3 EUV - Lamp Features of EUV-Lamp : easy to set-up and operate compact and efficient design user-friendly control long term stability environmentally sealed / ruggedized head no debris no special alignment spatial and temporal stability gaseous target operation with all gases VAC 50/60 Hz Pre-Prototype Version of 100 W EUV Lamp; Size of head will be < 60x60x50 cm Customer advantages fast, local access to EUV source simple operation low operation costs lower investment than LPP long term stability flexible no change of target necessary turn key push button

4 Hollow Cathode Triggered (HCT) Pinch Principle Cathode Concept : Z - pinch-plasma length : several mm diameter : < 500 µm low pressure discharge (left branch of Paschen-curve) homogenous volume-ignition Anode Scheme of HCT-Pinch geometry. Discharge ignition and pinch formation is inside the boreholes in the electrodes without insulator contact Advantages : no external switch needed no contact of plasma with insulator low pulse energy due to effective coupling low electrode erosion due to diffuse current high (> khz ) repetition-rates achievable large area for energy dissipation (cooling) large usable solid angle (up to π sr)

5 SPECTRAL YIELD [ µj/(sr nm pulse) ] Xe VIII Xe X Xe IX Area (total): 15.3 mj/(4π sr) OVI OV 2p-5d 2p-4d 2s-3p 2p-3d 2s 2-2s4p 2s2p-2s5d 2s2p-2p3p 2s 2-2s3p 2s 2-2s3p WAVELENGTH [ nm ] Emission spectrum of EUV Lamp when operated with Xenon resembles LPP emission Emission spectrum EUV Lamp when operated with Oxygen offers distinct line at 13 nm. Spectra can be engineered to your specification. Sample spectra are available for : Methane, Nitrogen, Oxygen, Fluorine, Neon, Argon, Krypton and Xenon

6 Emission Characteristics DIAMETER FWHM [µm] WAVELENGTH [nm] Source size as function of wavelength for EUV Lamp Temporal development of lamp voltage and EUV emission (electronically extended from 30 ns pulses) Typical emission characteristics: Source Size: < 500 µm Conversion (electrical ==> EUV) : 0,3 %/sr Repetition rate : Hz Conversion (2 % 13 nm) : 0,03 %/sr EUV Pulse duration: 30 ns Electrical Pulse Energy : 1-4 J Guaranteed lifetime> 10 7 Pulses

7 Applications Applications of EUV-Lamp EUVL at wavelength metrology Analytics Photochemistry Wavelength standard Calibration Source Experimental test source EUV-Lamp attached to reflectometer test stand AIXUV supports customers in adopting the EUV lamp to their individual application. Emission characteristics, interfaces, beamline, optics and detectors are tuned accordingly

8 Angular emission distribution 30 1 mm ,2 1,0 α Krit. Messung (Positiv) Messung (Negativ) Simulat ion Cathode Anode REL. INTENSITY 0,8 0,6 0,4 0,2 0, ANGLE α [ ] Accessible angle of 50 (with partially obscured) gives effective solid angle of 2sr

9 EUV Metrology Tools Source g Grating Pinhole b CCD ML 2 ML 1 Versatile diagnostic tool: Transmission Grating Spektrograph l/mm Resolution : λ/ λ > 100 Pinhole Camera Diameter < 35 µm ; Resolution X>50 µm Pinhole grating l/mm; 50 µm x 50 µm EUV- Inband Radiation Monitor Band selection by dual multilayer mirror reflection e.g. Plane SiMo-mirror; 60%reflectivity at 13.5nm Bandwidth (FWHM) ca. 0.7 nm from FhG-IOF additional out of band filtering Window (Siliconnitride + Zirconium, Beryllium) or Coated Diodes (Zirconium) Adopted Detectors Photodiode (G Hamamatsu) or CCD- Camera

10 Reproducibility Xenon 1,2 1,0 200 Synthetic Air 1,0 DIODE [ mv ] NORM. RATE 0,8 0,6 0,4 0,2 0,0 0,8 0,9 1,0 1,1 1,2 DIODE / <DIODE> DIODE [ mv ] NORM. RATE 0,8 0,6 0,4 0,2 0,0 0,8 0,9 1,0 1,1 1,2 DIODE / <DIODE> TIME [ min ] TIME [ min ] Fluctuations : rms = 3.6 % manual power control f=40 Hz, P el =130 W Fluctuations : rms = 1.7 % closed loop power control f=50 Hz, P el =100 W

11 Availabilty Schedule of availability of EUV-Lamp: Ordering Options : Prototype operation: November W Version 1. Shipment of α-version : April Shipment of ß-Version : June 2000 Production start : July 2000 (4 per year) Higher Power Versions : Working Gas of Choice (Standard: line emitter: Oxygen; Continuum : Xenon) Vacuum and Window interface to beamline and your application Repetition Rate (25, 50, 100 Hz) Special Options: Pulse to Pulse fluctuations stabilized Triggerable Variable Repetition Rate Gas Change during Operation, Special Gases Terms of Ordering : Terms of Ordering : Minimum production time : 4 Months in 2000 First order first shipped in 2000, 2001 Price : Standard EUV-Lamp : about 150 k$ (+special options) Guaranteed Operation : > 500 Hours for first Lamps > 5000 Hours planned