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Thin Metallic Layers Structured by E-beam Lithography
Horáček, Miroslav ; Kolařík, Vladimír ; Urbánek, Michal ; Matějka, František ; Matějka, Milan
The group of electron beam lithography runs the laboratory equipped with a shaped beam electron writer (BS600) and the basic technology for the lithographic process. The group is able to prepare micro and nano structures in thin layers of metals and other materials; including the characterization of the realized structures (using AFM, SEM, and CLSM). Within a few months (in the frame of the 'ALISI' project) a new e-beam writer with a better resolution will be installed; it will enable the realization of the actual structures in a better quality and the development of new structures with a very high innovation potential.
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Institute of Scientific Instruments: An Overview Presenatation
Kolařík, Vladimír ; Zobač, Martin ; Fořt, Tomáš ; Vlček, Ivan ; Dupák, Libor ; Mikmeková, Šárka ; Mikmeková, Eliška ; Mrňa, Libor ; Horáček, Miroslav ; Sobota, Jaroslav
The aim of this contribution is to present the Institute of Scientific Instrument of the Academy of Sciences of the Czech Republic, mainly from the potential of applied research viewpoint. It covers mainly the six application fields including material study of metals and alloys, nano layer residual stress observation methods, 2 kW fibre laser, impact testing of hard coatings, e-beam welding, machining and engraving, and finally e-beam lithography. Recently achieved results as well as the new application potential are presented. Furthermore, each topic is assumed to have a separate presentation prepared in more details within this event. A brief overview follows. Scanning low energy electron microscopy (SLEEM) is increasingly becoming recognized as a valuable analytical tool in the field of materials science. The SLEEM is also used for observation of compressive stress in nano layers that leads to wrinkling and film delamination. Using the fibre laser, we can offer 3D laser welding and cutting of various type of materials and laser surface hardening too. For the hard coatings testing and evaluation of their impact resistance a new method was suggested (Dynamic Impact Wear Test). During testing the specimen is cyclically loaded by tungsten carbide ball that impacts of the coating/substrate surface. In house e-beam welding machine allows for welding, machining, engraving and other utilizations of intense electron beam. The group of micro lithography is able to prepare micro and nano structures in thin layers of metals and other materials; including the characterization of the realized structures
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Proximity effect simulation for variable shape e-beam writer
Kolařík, Vladimír ; Matějka, Milan ; Urbánek, Michal ; Král, Stanislav ; Krátký, Stanislav ; Mikšík, P. ; Vašina, J.
Electron Beam Writer (EBW) is a lithographic tool allowing generation of patterns in high resolution. The writing is carried out into a layer of a sensitive material (resist), which is deposited on the substrate surface (e.g. silicon). The resolution of the EBW is limited not only by the beam spot size, but also by the electron scattering effects (forward scattering, backscattering). Thus, even if the beam spot size on the resist surface is very small, due to electron scattering effect in the resist, the exposed area is significantly broader than the original beam spot size [1, 2].
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What is the buzz about the TZ mode
Kolařík, Vladimír ; Matějka, František ; Matějka, Milan ; Horáček, Miroslav ; Urbánek, Michal ; Bok, Jan ; Krátký, Stanislav ; Král, Stanislav ; Mika, Filip
This contribution deals with an e-beam pattern generator BS 600 that works with a variable rectangular spot of electrons (stamp). The TZ stands for the ‘technology zoom’; its meaning is a reduction of the spot size by a factor of 3. Original description of the TZ exposure mode can be found in (1), [2] and [3]; further aspects concerning the exposure system and its electron source were described in [4] and [5]; technology and related topics are discussed in [6], [7], [8] and [9]; overview of application areas is in [10], [11] and [12]; and finally, very recent results are summarized in [13], [14] and [15].
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Thermal-field electron emission W(100)/ZrO cathode: facets versus edges
Matějka, František ; Horáček, Miroslav ; Kolařík, Vladimír ; Matějka, Milan
The tungsten cathode in the thermal-field emission (TFE) regime can achieve significantly higher angular current density in comparison with the Schottky cathode. The Schottky emission regime is located between the thermal emission regime and the cold field emission regime. The typical operation electric field is 0,1 - I V/nm and tip radius varies from 0.3 to 1.0 im . The thermal-field regime is located between the Schottky regime and the cold field emission regime. In the cold field emission regime the electron tunnelling is a dominant mechanism due to the electric field higher than 1 V/nm. The TFE is a combination of the field supported thermal emission and the field emission under the higher electric field. The radius of the thermal-field emitter should be lower in comparison with the Schottky emitter.
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Measurements of current density distribution in e-beam writer
Bok, Jan ; Kolařík, Vladimír
An e-beam writer with a variable shaped beam needs a bright and stable source of electrons but also a homogeneous square beam segment. This is the starting element out oif wich smaller rectangular-shaped variable-sized patterns are selected (stamps). Current inhomogeneity of the starting element would cause and different current density of various stamps that negatively impacts the exposure quality. This problem implies the necessity of analysing and monitoring the current density distribution in the staring beam element.
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Scanning Probe Microscopy: Measuring on Hard Surfaces
Matějka, Milan ; Urbánek, Michal ; Kolařík, Vladimír
During a measurement by scanning probe microscopy (SPM) an image artifacts can appear in a measurement data. The source of image artifacts during an SPM measurement could be in parts of the SPM tool: mechanical system, piezoelectric crystal, scanner electronic. However, the main source of image artifact is the probe tip geometry and properties of the sample. For example, probe wearing, which occurs during the contact measurement on a sample with a hard surface, could result in heavy probe shape change, causing probe-related image artifacts. Measurement could appear problematic on a sample with periodical relief structure (e.g. gratings with sub 10 μm periodicity) prepared in hard materials (e.g. silicon), when the structure height is greater than about 500 nm. In this case, probe can easily get struck during the scanning, on the hard surface as well as at the high aspect ratio relief structure, causing image artifact thus reducing measurement quality.
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SPM Nanoscratching in the Sub 100 nm Resolution
Urbánek, Michal ; Kolařík, Vladimír ; Matějka, Milan
Scanning probe microscopy (SPM) is tool basically used for surface characterization. Besides that, it offers several lithographic methods (e.g. nanoscratching) to prepare structures in the sub 100 nm resolution. The nanoscratching using SPM offers a method for patterning of surface with a very high resolution based on near field interaction. By this method some tiny marks or taggants could be prepared. Therefore we used the SPM nanoscratching for preparation of nanostructures in thin soft polymer films by various tips. Nanoscratching regime of SPM is possible to operate in contact and close contact modes. In the contact mode we prepared an array of stamps with a variable size, where dimensions and depth dependency on number of pixels were inspected. For writing of these structures we used polymer films with different softness (e.g. PMMA, SU-8) and various values of setpoint, which are responsible for structures deepness.
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