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A new beam homogenizer device which leaves the beam parameter product almost unaffected is presented. Excimer laser beams usually show a nearly Gaussian beam profile along the short beam axis whereas along the long beam axis a nearly flat-top profile is provided. The new beam homogenizer efficiently converts the short beam axis into a top-hat profile featuring nearly the same divergence as the incoming laser beam. Depending on the output beam profile of the excimer laser the homogenizer presented provides a beam profile with a homogeneity of ±5% to ±10% within an area covering 65% to 70% of the total pulse energy.

The observation of systematic variations of the shape of holes drilled along a line into polyimide by excimer laser-based mask imaging and ablation stimulated this investigations. Despite homogeneous illumination of the total line of holes in the mask, the exit diameters of the holes drilled in the inner part of the line were smaller with respect to those of holes situated near both ends of the line; the entrance diameters were all equal within experimental variation. It was found that plasma plume ejection from the holes leads to a cloud of material which is optically denser above the inner holes so that the excimer laser radiation is attenuated there stronger than above the outer holes.

Laser based crystallization of thin amorphous films on glass substrates have entered into industrial applications since several years. The excimer laser based process provides a low temperature procedure to obtain polycrystalline silicon films on flat panel display substrates to fabricate thin film transistors (TFT's).The key to this application is a uniform illumination of the. Line Beam systems provide up to 365mm long homogeneous exposure fields operated with up to 300 W average power 308nm excimer lasers. The paper covers a technical overview of Line Beam Optics layout, recent developments and results.Further high resolution optics are described and discussed for sequential lateral solidification (SLS) (1,2,3) processes. The SLS application has demonstrated to efficiently produce directionally solidified microstructures or even grain-boundary –free regions on Si-films. Diffraction limited resolution in the range of several micrometers and high optical throughput are important parameters to this application.General considerations are presented to describe technical limits which compromise laser beam related coherence effects, optimum uniform illumination, adequate resolution and depth of focus and optical efficiency for the practical application.

Optical illumination parameters such as principal ray tilt and numerical aperture of illumination (NA: divergence or light cone angle) play a dominant role in the generation of well defined microstructure wall angles. High power (up to 200 W, Lambda 4000) Excimer Lasers with pulse energy up to 700 mJ are applied to ablate polyimide at 248 nm and 308 nm using a new 5x large field lens. As zoom lens homogenizer set up is used to arrange a numerical aperture of 0.13. Results of a systematic study with beam delivery systems of different NA are presented. The variation of the numerical aperture clearly results in steeper walls at higher NA. The impact of the applied energy density is investigated over a range of 100 mJ/cm2 to 11 J/cm 2.

Excimerlaser werden seit einigen Jahren vermehrt in industiellen Fertigungsprozessen eingesetzt. Fur diese Laser gelten andere Anforderungen als an Laser, die im wissenschaftlichen oder medizinischen Bereich eingesetzt werden.

The technique of double translational spectroscopy is applied in order to study electron capture by state-selected multiply charged ions. The projectile ions are prepared in specific atomic states by electron capture in an initial gas target with succeeding energy analysis. The studied capture reaction takes place in a second collision chamber. The final-state population being measured by the energy gain of the projectile ions. The advantages of this method as well as new experimental possibilities are discussed by means of the collision systems Ar3+(*)-Ar and Ar2+(*)-He, Ne.

Total and differential cross sections for charge transfer of Arzeta + and Krzeta + (2 or=4 cross sections are found to scale with zeta . For zeta

At collision energies below 1 keV electron transfer processes were studied in the collision system Ne2+-Xe. By applying high-resolution translational spectroscopy 12 different reaction channels are separated corresponding to pure electron capture reactions as well as transfer ionisation processes. In the energy range studied, the mechanism of the transfer ionisation is described as a two-step process: after one electron is captured by the Ne2+ ion, the Xe+ target ion is ionised by a Penning-type process at nuclear distances near 5 a0. The influence of metastable projectiles on the measured kinetic energy spectra is discussed.

The composition of a primary Ar2+ ion beam is analysed with respect to 3P, 1D and 1S states by aid of the translational attenuation method (TAM). The corresponding fractions are found to be 0.48, 0.37 and 0.15, respectively. Measurements with the analysed beam show that electron capture by slow Ar2+ ions depend sensitively on the initial projectile state population. Whereas in the Ne target Ar2+(3P) ions give the main contribution to the electron capture reaction, in the He target the metastable 1D2 state of Ar2+ is more effective by a factor of about 19. Finally, in krypton the translational spectrum is dominated by reactions of Ar2+(1S0).

A small and inexpensive electron beam ion source for multiply charged ions of noble gases is described. One of its essential characteristics is the low energy spread of the extracted ion beam, which depends on the charge state q of the ions and amounts to ∽q × 50 meV. The total ion current containing ionic states up to q = 6 is in the order of 10 nA. The design, construction and important parameters of the ion source are described. Eine einfache Ionenquelle fur monoenergetische Bundel mehrfach geladener Ionen Wir beschreiben eine kleine und ohne grosen Aufwand herstellbare Elektronenstosquelle fur mehrfach geladene Ionen von Edelgasen. Eine ihrer hervorragendsten Eigenschaften ist die geringe Energiebreite des extrahierten Ionenbundels. Diese Energiebreite hangt von der Ladungszahl q der Ionen ab und betragt etwa q × 50 meV. Der extrahierte Ionenstrom betragt etwa 10 nA und enthalt Ladungszustande bis zu q = 6. Funktion, Wirkungsweise und wichtige Betriebsparameter der Ionenquelle werden beschrieben.

With the aid of translational spectroscopy the authors studied the electron capture of Xe2+ and Ar3+ projectiles in molecular hydrogen at low energies (Ecm=6 and 29 eV). The measurements yield information on the vibrational excitation of the molecular target ion H2+, showing the dominant population of the levels nu '=1-4. The results are discussed in terms of the energy defect Delta E and the Franck-Condon factors Cvv'.

By the aid of translational spectroscopy the authors have studied the production of Ne+ ions in Ne2+-Xe collisions with an improved energy resolution (E/ delta E approximately 3000) obtaining a better identification of the reception channels. The interpretation of the spectrum has to be changed as compared with the earlier publication. The spectrum emphasises the importance of Ne2+(1D2) ions for both electron capture and transfer ionisation at low collision energies (

Single electron capture processes in Ne2+/Ar, Kr collisions were studied by aid of the high-resolution translational spectroscopy. At low collision energies (

Excimer laser marking, profiling and drilling are usually not performed at the focal region of a lens. It is usually more economical to optimize a process at a relatively low energy density and process larger areas at an image plane of a lens system. Internal(within the resonator, i.e. intracavity) methods as well as external methods are used to achieve goal.

A single stage excimer laser for UV microlithography has been developed. It emits 2 Watt average power at about 248.4 nm with a bandwidth of 0.5 cm -1. A novel computer-controlled feedback circuitry provides for automatic stabilization of both average power and integrated bandwidth. In addition, a computer-controlled frequency stabilization unit makes that new laser ready for industrial use as light source in deep UV microlithography.

Experiments have shown that a significantly enhanced energy transport via quartz fibers is achieved by using a long-pulse excimer laser. The technology used to generate 250 ns excimer laser pulses is described. Additionally it is reported on considerations leading to the design of an excimer laser fiber coupler. Measured data are presented.

Excimer laser material processing of technical parts leads to results which, in many cases, differ strongly from previously known effects. This paper is a review on processing of metals, plastics, glass, ceramics, and compound materials. Since the effect of radiation is determined by beam parameters, beam handling will be described as well. Starting with the beam properties of interest, the technique and results of excimer laser processing will be summarized.© (1989) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Various industrial microprocessing applications of excimer lasers will be reviewed as well as the requirement and suitability of excimer lasers for each application. 1. INTRODUCTION Excimer lasers excel in micromachining because the unique properties of pulsed ultraviolet light can be used to remove fine amounts of material or alter the properties of the product with high finesse. Typical materials which have been effectively drilled, cut and/or marked with an excimer laser beam include plastics, metals, ceramics and hard dielectrics.A diamond, for example, is a material which belongs to an unusually difficult group of materials for laser processing due to its unique optical properties. As the optical transmission curve would indicate, (Figure 1) the ArF laser at 0.19 (im is the best laser choice for finish micromachining. Testing in Lambda Physik application laboratories indicate that even KrF lasers create some charring and heat effects which are completely absent with the ArF laser.Likewise, metals, ceramics, glass, and plastics have better absorption characteristics in the ultraviolet region than in the visible or infrared. In many cases a material has absorption peaks within the UV range of 193 to 351 nm, which allows a specific excimer wavelength to be an optimum choice.Because ultraviolet light is usually absorbed in fine layers of a material, this allows less energy per unit area is used to effectively ablate off thin volumes. The combination of high peak power and short pulses can be used to remove larger interaction areas than lasers with longer absorption depths, and heat is carried away via kinetic energy of the ablated matter.The extremely clean material removal achieved with an excimer laser contrasts greatly with the rough charred and melted results produced with a YAG or CC>2 source.

Optische Projektions-Mikrolithographie mit Wafer-Steppern ist eine etablierte Methode der Halbleiterherstellung. Das Verfahren besteht darin, die Struktur einer Maske mittels eines Objektivs auf einen mit Photolack beschichteten Wafer abzubilden. Dabei wird das Bild typischerweise um einen Faktor 5 verkleinert.

Excimer lasers emitting more than 200 W output power are not commercially available. A significant increase requires new technological efforts with respect to both the gas circulation and the discharge system. A due research project has yielded a laser which emits 0.5 kW at 308 nm when being UV preionized and operated at a repetition rate of 300 Hz. The laser, which is capable of operating at 500 Hz, can be equipped with an X-ray preionization module. After completing this project 1 kW output power will be available.

In addition to the conventional use of metal coatings on glass for mirrors, the electrical and electronic industries have increasing demand for patterned metal films on polymer substrates.