Average power scaling of 308nm excimer lasers has followed an evolutionary path over the last two decades driven by
diverse industrial UV laser microprocessing markets. Recently, a new dual-oscillator and beam management concept for
high-average power upscaling of excimer lasers has been realized, for the first time enabling as much as 1.2kW of
stabilized UV-laser average output power at a UV wavelength of 308nm. The new dual-oscillator concept enables low
temperature polysilicon (LTPS) fabrication to be extended to generation six glass substrates. This is essential in terms of
a more economic high-volume manufacturing of flat panel displays for the soaring smartphone and tablet PC markets.
Similarly, the cost-effective production of flexible displays is driven by 308nm excimer laser power scaling. Flexible
displays have enormous commercial potential and can largely use the same production equipment as is used for rigid
display manufacturing. Moreover, higher average output power of 308nm excimer lasers aids reducing measurement
time and improving the signal-to-noise ratio in the worldwide network of high altitude Raman lidar stations. The
availability of kW-class 308nm excimer lasers has the potential to take LIDAR backscattering signal strength and
achievable altitude to new levels.
The growing demand for laser micro fabrication drives further requirements on higher production speed per part and
lower manufacturing costs. A newly developed 1.2 kW 308 nm excimer laser addresses both micro-manufacturing and
high production throughput.
Solid state UV laser sources usually cannot emit UV laser radiation directly. The inherently required frequency
conversion limits the total output power to several 10 Watts below 350 nm. Furthermore these UV-conversion- modules
limit the long term reliability of high power UV solid state lasers significantly because of the wear of the conversion
crystals. Excimer lasers, however, overcome these issues by direct emission at 308, 248, or 193 nm. By now up to 540
Watts at 308 nm are established in production. With the new laser we have more than doubled the available output power
to 1.2 kW.
The combination of short wavelength and highest available UV laser power makes it ideal for processing of small
features or to modify thin surfaces. Furthermore, pulsed UV laser radiation is very suitable for removing delicate
electronic devices from manufacturing substrates.
High-power UV laser systems are capable of processing large areas with resolution down to several microns in one
single laser ablation step without using multiple lithography and wet chemical processes. For instance, laser Lift-Off and
large area annealing have proven to be very efficient manufacturing techniques for volume production. In this paper, a
novel 1.2 kW excimer laser will be presented and discussed.
The paper presents a review of the most recent achievements in the development of the industrial high power excimer
lasers. The results of the development of a XeCl laser with the output energy above 900mJ and the pulse repetition
frequency up to 600Hz will be demonstrated. The system performance such as energy, stability, spatial and temporal
properties of the laser pulse as well as the extended maintenance cycles and finally low cost of operation in industrial
applications will be discussed. Special emphasis will be placed on the design of the laser chamber and the pulsed power
module, enabling the generation of a reproducible and homogeneous gas discharges which is indispensable for the
required laser performance over the whole range of the laser output power.
UV lasers are well-established sources for a wide variety of micro-machining applications. The small wavelength makes
them ideal for processing of small features or to modify thin surfaces. Especially short pulse UV lasers are ideal for
ablation of various materials, e. g., polyimide, parylene, PMMA, copper, gold and diamond. Furthermore these lasers are
used for silicon annealing and patterning of fine circuitries to various substrates. The demand for smaller feature sizes of
micro-mechanical and micro-electronic devices set new requirements in regard to resolution, throughput and overall cost
efficiency of the process.
In this paper, high-power excimer laser micro-machining and annealing relevant applications will be presented and
High power excimer lasers are well established as work horses for various kinds of micro material processing. The
applications are ranging from drilling holes, trench formation, thin film ablation to the crystallization of amorphous-Si
into polycrystalline-Si. All applications use the high photon energy and large pulse power of the excimer technology.
The increasing demand for micro scale products has let to the demand for UV lasers which support high throughput
We report the performance parameters of a newly developed XeCl excimer laser with doubled repetition rate compared
to available lasers. The developed laser system delivers up to 900 mJ stabilized pulse energy at 600 Hz repetition rate.
The low jitter UV light source operates with excellent energy stability. The outstanding energy stability was reached by
using a proprietary solid-state pulser discharge design.
Today's excimer lasers are well-established UV laser sources for a wide variety of micromachining applications. The excimer's high pulse energy and average power at short UV wavelengths make them ideal for ablation of various materials, e. g., polyimide, PMMA, copper, and diamond. Excimer micromachining technology, driven by the ever-shrinking feature sizes of micro-mechanical and micro-electronic devices, is used for making semiconductor packaging microvias, ink jet nozzle arrays, and medical devices. High-power excimer laser systems are capable of processing large areas with resolution down to several microns without using wet chemical processes. For instance, drilling precise tapered holes and reel-to-reel manufacturing of disposable sensors have proven to be very cost-effective manufacturing techniques for volume production. Specifically, the new industrial excimer laser-the LAMBDA SX 315C-easily meets the high demands of cost-effective production. The stabilized output power of 315 watts at 300 Hz (308 nm) and its outstanding long-term stability make this laser ideal for high-duty-cycle, high-throughput micromachining. In this paper, high-power excimer laser technology, products, applications, and beam delivery systems will be discussed.
Laser annealing has become the primary method for producing the Low-Temperature-Poly-Silicon (LTPS) panels used in the Flat Panel Display (FPD) industry. Thin Film Transistor (TFT) backplanes based on LTPS substrates for Active Matrix Liquid Crystal Displays (AMLCD) offer substantial advantages over TFT backplanes based on amorphous silicon. The trend to higher pixel density, the integration of more driver and logic ICs on the glass, and the advent of Active Matrix Organic Light Emitting Displays (AMOLED) all have lead to significant interest in the laser annealing process. Currently, there are several different approaches to the annealing process based on excimer lasers, cw-green DPSS lasers, modelocked-green DPSS lasers and Q-switched Nd:YAG lasers. This paper reviews the various laser technologies and annealing techniques, such as the line beam method and Sequential-Lateral-Solidification (SLS). These approaches will be compared in terms of crystal quality, electron mobility, throughput, yield and operating cost.
Laser micromachining has become a key enabling technology in the ever-continuing trend of miniaturization in microelectronics, micro-optics, and micromechanics. New applications have become commercially viable due to the emergence of innovative laser sources, such as diode pumped solid-state lasers (DPSSL), and the progress in processing technology. Examples of industrial applications are laser-drilled micro-injection nozzles for highly efficient automobile engines, or manufacturing of complex spinnerets for production of synthetic fibers. The unique advantages of laser-based techniques stem from their ability to produce high aspect ratio holes, while yielding low heat affected zones with exceptional surface quality, roundness and taper tolerances. Additionally, the ability to drill blind holes and slots in very hard materials such as diamond, silicon, sapphire, ceramics and steel is of great interest for many applications in microelectronics, semiconductor and automotive industry. This kind of high quality, high aspect ratio micromachining requires high peak power and short pulse durations.
Excimer lasers are nowadays well established UV laser sources for the wide area of micromachining. Their high energy and average power at short UV wavelengths makes them ideal for ablation of various materials e. g. polyamide and PMMA. The typical excimer laser sources used in micro machining deliver several hundred mJ of energy at repetition rates of up to 400 Hz. In parallel to this high-energy-micromachining an alternative excimer based method came up during the last years. This new technology is driven by the ever shrinking feature sizes of microelectronic circuits and utilises UV wavelength resist exposure. The resist exposure technology offers new possibilities also for micromachining. It is ideal for micro applications which require high precision patterning - with a positional accuracy of below 50 microns - at high volume throughput. In this process the laser energy dose may be built up in several shots, UV lasers with several hundred mJ cannot be utilised. Hence, high repetition rate lasers are needed.
In this paper the basic feature and performance characteristics of the new laser will be presented.
Industrial production of low temperature p-Si back plates for LCDs by high power excimer laser annealing was introduced several years ago. Regarding the economy of the process, one of the major advantages of excimer laser annealing is the opportunity to make use of low cost glass substrates due to the low temperature of the annealing process. The Lambda Physik high power excimer laser series are operated with the MicroLas 370 mm line beam optics, integrated by Japan Steel Works into industrial systems. The MicroLas line beam optics for conventional excimer laser annealing (ELA) process converts the raw laser beam profile into a stable and homogeneous rectangular illumination field with high aspect ratio. The excimer laser light source, the LAMBDA STEEL 1000, delivers stabilized pulse energies up to 1 Joule at repetition rates up to 300Hz. The crystallization using excimer lasers allows to produce films with electron mobility of 100-150 cm2/Vsec with the Line beam technique. The new SLS-method, which is currently under industrial investigation, even allows to obtain electron mobility between 200-400 cm2/Vsec.
During the last decade the development of fiber Bragg gratings (FBG) was forced by the ever growing demand on data transmission capacity. Fiber Bragg gratings support as filters, amplifiers, and stabilizers the entire optical network philosophy avoiding optical to electrical signal conversion. Whereas in the early 1990s the most gratings were manufactured by researchers with continuous wave (cw) laser sources, the excimer laser became a common tool for high throughput writing of Bragg gratings in the mid 1990s. The excimer laser is nowadays still the most efficient UV laser source which leads to low cost of operations compared to other UV sources. This paper presents the possibilities and advantages of excimer lasers in regards to writing of fiber Bragg gratings.