RnD ISAN
`
`RnD-ISAN LLC
`www.rnd-isan.ru
`info@rnd-isan.ru
`
`XWS
`
`LASER PUMPED
`PLASMA BROADBAND
`LIGHT SOUCE
`
`Energetiq Ex. 2039, page 1 - IPR2015-01375
`
`

`
`RnD ISAN
`
`RnD-ISAN (limited liability company) is an independent
`high-tech company, established by a group of
`professionals in the field of novel ultraviolet and extreme
`ultraviolet light sources. Company is created on the base
`of Institute of Spectroscopy, Russian Academy of Sciences
`(ISAN) for doing research and development work with
`further commercialization of work results.
`
`Main activity of the company lies in the area of
`multidisciplinary applications of plasma physics, optical
`and x-ray spectroscopy, light sources and gas discharge
`physics.
`
`The company combines long-term experience with
`experimental work in various fields of physics and with
`numerical modeling of physical processes. This unique
`combination is a key advantage of the company.
`
`Our company focuses on application of modern plasma
`technologies to science and industry. Our interests
`include, but not
`limited
`to, plasma
`technology
`applications, plasma chemistry, light sources for EUV
`lithography and optical nanodiagnostics.
`
`Concepts developed by the company are used, for
`example, in EUV lithography, a complex technological
`process used in production of modern highly integrated
`microelectronic devices. Dozens of solutions developed
`by our company are patented in EU, USA, Japan and other
`countries.
`
`Moreover, our company is involved in a broad range of
`related activities. We respond rapidly to demands of a
`very dynamic high-tech market. These activities include
`design, manufacture and sales of scientific equipment, of
`high-tech equipment such as spectrometers,
`light
`sources and metrology systems for different spectral
`regions.
`
`We are open for cooperation. The company is very active
`in contract research and development, as well as in IP -
`intensive business activities originating from various
`fields of modern science and industry.
`
`Energetiq Ex. 2039, page 2 - IPR2015-01375
`
`

`
`Laser pumped plasma broadband light source XWS
`
`XWS is a novel bright UV-VIS-IR light source. Operating principle is based on a
`physical phenomenon of optical discharge in gases, maintained by a focused laser
`beam. Working medium is Xenon at high (~20 atm) pressure.
`Discharge in gas is initiated by a high
`voltage breakdown. Continuous wave
`laser beam is focused onto initial gas
`breakdown volume and delivers power
`sufficient to maintain plasma state.
`High power densities significantly
`exceeding 200 kW/cm2 required to
`maintain a continuous optical discharge
`are created in a small volume by a
`focused laser beam.
`Shape and dimension of a
`light
`emitting plasma column depend in
`particular on laser power input and numerical aperture of the pump laser. Typical light
`source dimensions are (0.3 x 0.7) mm, NA=0.35 for a 64W laser.
`High spectral brightness in a broad spectral range from 200 nm to 800 nm is mainly
`a result of high temperature gradients within plasma column.
`A highly ionized plasma is located in the center of the optical discharge volume. The
`laser energy is effectively converted into thermal energy by inverse bremsstrahlung
`channel.
`An outer discharge zone consists of a weakly ionized, low temperature plasma,
`heated by the heat flux from the center region. The outer discharge zone is a main
`contributor to the emission of VIS and UV parts of the light spectrum. High temporal
`stability of light emission parameters (3σ < 0.1%) is achieved by controlling coupling
`of the laser power to the plasma.
`XWS light source is characterized a number of advantages compared to other
`commonly used light sources:
` - High spectral brightness
`- Broad spectral range (UV to IR)
`-
`Long lifetime (electrodes used only during plasma ignition)
`- Uniform emission spectrum in broad range
`-
`Small dimensions of light emitting volume
`- High power
`- High light emission stability
`
`1
`
`Energetiq Ex. 2039, page 3 - IPR2015-01375
`
`

`
`Schematic of a laser pumped plasma broadband light source
`XWS
`
`9
`10
`168 White light
`7
`
`source
` feedback
`loops
`
`Light source ignition:
`
`1. RF discharge creates initial
`plasma cloud
`
`2. Laser delivers energy to
`plasma and keeps the light
`source in a stable regime.
`
`5
`
`8
`
`6
`
`4
`
`3
`
`2
`1. Laser controller;
`2. Cooling system;
`3. Diode laser with optical �iber output (980nm);
`4. Focusing optics;
`5. RF ignition unit;
`6. Xe high-pressure lamp;
`7. Laser light �ilter;
`8. Photodiode for the control loop;
`9. Laser light dump;
`10. Light source shape.
`
`1
`
`54
`Xe
`
`Energetiq Ex. 2039, page 4 - IPR2015-01375
`
`

`
`Description of a laser-pumped plasma broadband light source
`XWS
`
`Broad spectral range and high spectral brightness
`
`plasma
`pumped
`Laser
`broadband light source XWS emits
`light in 200-800nm range with high
`spectral brightness. Thanks
`to
`emission in UV, VIS and IR ranges it
`can be used as a substitute for
`conventional continuous spectrum
`lamps (deuterium-, xenon arc-,
`xenon pulsed-, halogen and plasma
`lamps) as well as lamps emitting
`single spectral lines (metal-halid,
`Hg arc lamps).
`Broad spectrum with inclusion of
`UV range allows using XWS sources
`as a substitute of photodiodes in
`applications where UV is required.
`Spectral brightness of the XWS
`source is 7-8 times higher than that
`of Xe lamps. Moreover, in contrast
`to Xe lamps, XWS sources do not
`suffer
`from a
`steep
`spectral
`brightness
`drop-off
`for
`wavelengths below 300nm, which
`allows using the XWS as a UV
`source.
`Compared to deuterium lamps,
`brightness of the XWS light source
`is about one order of magnitude
`higherPower of the XWS source can be
`varied in wide limits depending on
`the used laser. A fiber coupling of
`laser power to plasma allows using
`different laser types. Lifetime of
`XWS sources is mainly limited by
`laser lifetime and can be renewed
`by replacing a laser unit.
`3
`
`Brightness, W/m2
`×104
`7.0
`200
`
`300
`
`400
`
`500
`
`∫ – transmission of interference �ilters λ, nm
`800
`900
`1000
`600
`700
`1100
`Fiber laser, 1070 mn
`120 W
`λ, nm
`
`∫
`2.28
`1.72
`2.32
`2.73
`6.56
`5.64
`5.17
`3.72
`6.11
`7.01
`4.75
`2.28
`5.05
`2.74
`2.73
`5.31
`8.4
`4.46
`9.06
`
`200
`250
`300
`350
`375
`400
`425
`436
`450
`475
`500
`525
`550
`600
`650
`700
`750
`800
`850
`
`6.0
`
`5.0
`
`4.0
`
`3.0
`
`2.0
`
`1.0
`
`0.0
`
`Diode laser, 980 nm
`167 W
`
`64 W
`40 W
`
`200
`
`300
`
`400
`
`500
`
`600
`
`700
`
`800
`
`900
`
`1000
`
`1100
`λ, nm
`
`Energetiq Ex. 2039, page 5 - IPR2015-01375
`
`

`
`Stability of a laser pumped plasma broadband light source
`XWS
`
`Size of radiating body
`
`The direction relative to the laser beam
`
`d=0.3 mm
`
`l=0.7 mm
`
`Stability conditions: 50÷150 W
`
`Effect of a laser power and beam direction on the shape and dimensions of radiating
`body
`
`W
`
`74
`
`98
`
`120
`
`144
`
`167
`
`187
`
`205
`
`0.44×0.57
`
`0.46×0.6
`
`0.47×0.65
`
`0.51×0.73
`
`0.54×0.81
`
`0.6×0.99
`
`0.72×1.51
`
`d×l, mm
`
`0.31×0.56
`
`0.36×0.62
`
`0.4×0.65
`
`0.45×0.72
`
`0.5×0.83
`
`0.61×1.07
`
`0.72×1.39
`
`Lifetime and temporal stability
`
`Lifetime of the XWS source is comparable to lifetimes of modern lasers and reaches tens of
`thousands hours.
`Emission characteristics and position of the emitting body in space are highly stable and
`reproducible.
`Temporal intensity variation is <0.1% during 5-20ms time interval.
`Longterm stability of the source output is maintained by a control loop, which drives temporal
`intensity variations to below 0.1% during a period of 8 hours.
`XWS source design allows minimizing ozone emission to the environment.
`
`Ozone-free technology
`
`4
`
`Energetiq Ex. 2039, page 6 - IPR2015-01375
`
`

`
`Applications of laser pumped plasma broadband light source
`XWS
`
`Light source for chemo-physical
`separation methods
`
`Microscopy and microanalysis for
`promising technologies
`
`Medical visualization and spectral
`analysis systems
`
`Modern separation techniques are required to yield confident
`detection of various substances and compounds
`in
`low
`concentrations, excel in probe volumes, stay fast in order to
`enable registration of substances with simultaneously low
`concentrations and short confinement times
`It is necessary to maximize variety of detected substances
`using fluorescence, UV and VIS absorption techniques.
`A broadband light source, high spectral brightness and small
`spatial dimensions for better optical focusing has a large area of
`potential applications, in particular detection systems for gas and
`fluid chromatography, capillary electrophoresis, blotting, flow
`cytometry and other related analysis methods.
`Broadband light sources with high spectral brightness can be
`readily used in applications requiring uniform illumination of
`objects, utilizing focusing optics, and using spectral ranges from
`VIS to UV.
`Here we may note several microscopy techniques as an
`application area of the light source. These are fluorescence,
`dark-field, confocal microscopy with broadband light sources.
`These microscopy techniques present challenging requirements
`to a light source. Thanks to unique parameter combination of the
`XWS lamp these microscopy techniques can be further improved.
`The XWS light source can find its applications also in other
`modern microanalysis techniques such as droplet spectrometry,
`microfluidics chips, lab-on-a-chip, various microarrays for bio
`applications
`XWS light sources can be applied for
`- medical visualization tasks (surgical field illumination,
`endoscopy, visualization of tissues marked with fluorescent dyes,
`optical tomography);
`-
`therapeutic applications (e.g. photodynamic therapy,
`treatment of skin diseases);
`-
`Scanners for medical diagnosis scanners (Hyper-spectral
`scanners can aid in diagnostics, monitoring course of diseases,
`etc. )
`5
`
`Energetiq Ex. 2039, page 7 - IPR2015-01375
`
`

`
`Con�iguration and applications of laser pumped plasma
`broadband light source XWS
`
`Con�iguration options
`
`Laser type
`
`Laser power
`
`XWS - 000
`
`Laser power
`
`Cooperation
`
`Laser direction
`
`Light output:
`
`open geometry light source
`via optical �iber
`
`Light source XW is offered as a standalone product. Customers can choose con�igura-
`tion and delivery terms.
`
`We propose modi�ications to the source design according to customer requests and
`speci�ications. Then integration with the customer technology is done.
`
`We offer integration of XWS light sources into our customers’ equipment, assistance
`in choosing the best con�iguration as well as carrying out necessary design modi�ica-
`tions.
`
`Light source XWS is offered as a technology.
`Customer receives a technology of the XWS light source.
`
`An example of a technology transfer
`
`RnD ISAN
`
`6
`
`One of the approaches to monitor and tune a photolithography process involves analysis of
`diffraction patterns from test structures at different wavelengths.
`Such systems usually utilize a Xe short-arc lamps with optical filters as light sources. It is
`expected that speed and quality of the analysis will benefit from increasing spectral
`brightness, time stability of a light source as well as from extension of light source spectrum to
`ultraviolet region.
`RnD ISAN carried out a research work on request of ASML, which resulted in development of
`a special light source. The
`technology was transferred
`to Qioptiq for integration
`into ASML’s LISA system.
`
`Yield Star
`
`Prototype
`
`LISA-IV
`
`Energetiq Ex. 2039, page 8 - IPR2015-01375