Measured optical constants of copper from 10 nm to 35 nm

Brimhall, Nicole; Herrick, Nicholas; Allred, David D.; Turley, R. Steven; Ware, Michael; Peatross, Justin

doi:10.1364/oe.17.023873

Cited by 21 publications

(11 citation statements)

References 18 publications

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“…This result was unexpected because oxidation rates previously reported on bulk samples suggest a slower room-temperature oxidation rate, approximately 0:37 nm=h [18,19]. This rate suggests that we should have been able to see the oxide thickness growing, something we recently observed for copper [7]. Atomic force microscope (AFM) measurements showed that our uranium films had less than 1 nm rms roughness on a 1 μm × 1 μm scale.…”

Section: Deposition Of Uranium and Measurementssupporting

confidence: 62%

“…Unfortunately, the optical properties of relatively few materials are well-characterized in this wavelength range [4][5][6]. For example, we recently found that accepted optical constants for copper in the EUV were incorrect due to inadvertent sample oxidation [7]. A lack of experimental characterization is especially common for materials in the actinide series, where reactivity, toxicity, and (sometimes) radioactivity adds challenges to taking optical measurements.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of optical constants for uranium from 10 to 47 nm

et al. 2010

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We use a laser high-harmonics-based extreme-ultraviolet (EUV) polarimeter to determine the optical constants of elemental uranium in the wavelength range from 10 to 47 nm. The constants are extracted from the measured ratio of p-polarized to s-polarized reflectance from a thin uranium film deposited in situ. The film thickness is inferred from a spectroscopic ellipsometry measurement of the sample after complete oxidation in room air. Uranium has been used as a high-reflectance material in the EUV. However, difficulties with oxidation prevented its careful characterization previous to this study. We find that measured optical constants for uranium vary significantly from previous estimates.

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Section: Deposition Of Uranium and Measurementssupporting

confidence: 62%

Section: Introductionmentioning

confidence: 99%

Characterization of optical constants for uranium from 10 to 47 nm

et al. 2010

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“…So, in our deposition case, the thickness of copper was in the sub-micrometer range. The absorption depth of copper in the visible range of the light spectrum is tens of nanometers 32 33 34 35 and is the order of magnitude smaller than the thickness of deposited copper layer. Therefore, the colour was not influenced by the thickness of the metal layer.…”

Section: Resultsmentioning

confidence: 99%

Colour-Difference Measurement Method for Evaluation of Quality of Electrolessly Deposited Copper on Polymer after Laser-Induced Selective Activation

Gedvilas

Ratautas

Kacar

et al. 2016

Sci Rep

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In this work a novel colour-difference measurement method for the quality evaluation of copper deposited on a polymer is proposed. Laser-induced selective activation (LISA) was performed onto the surface of the polycarbonate/acrylonitrile butadiene styrene (PC/ABS) polymer by using nanosecond laser irradiation. The laser activated PC/ABS polymer was copper plated by using the electroless copper plating (ECP) procedure. The sheet resistance measured by using a four-point probe technique was found to decrease by the power law with the colour-difference of the sample images after LISA and ECP procedures. The percolation theory of the electrical conductivity of the insulator conductor mixture has been adopted in order to explain the experimental results. The new proposed method was used to determine an optimal set of the laser processing parameters for best plating conditions.Polymer-based electrical devices are used in different areas such as optical communications, biomedicine, and automotive industry 1,2 . Formation of the electrical circuits on polymers is important for these devices. There are many techniques called "selective metallization" to produce a circuit on the surface of polymers: direct chemical plating 3 , laser direct structuring (ablation and writing) 4,5 , laser direct imaging 6 and laser-induced selective activation (LISA) [7][8][9][10][11] .LISA was developed for selective metallization of polymers for three-dimensional moulded interconnecting devices. This method contains single step: laser structuring of the polymer surface. As a result of the laser structuring, sponge-like and nano-porous structures are created to improve the adhesion strength of the metal to the polymer. After LISA process the metal layer is deposited by the electroless copper plating (ECP) procedure. The ECP contains of three-steps: activation of the laser-structured surface with palladium colloidal activator; cleaning with distilled water; electroless deposition of copper layer on the activated sample. In the activation procedure, palladium atoms are trapped in a porous sponge like structures on the polymer surface. Cleaning with distilled water removes unwanted palladium from flat unstructured polymer and leaves it confined in the poriferous surface. The copper fills all the openings in the polymer and a porous, rough metal film is deposited during the final step of the ECP. Finally, after both, LISA and ECP procedures, the copper layer is deposited selectively only onto the laser structured areas while unstructured polymer is not coated with the metal deposition.The electrical and optical properties of the semi-transparent films were investigated in numerous works [12][13][14][15][16][17][18][19] . However, the analysis of the sheet resistance dependence on the optical transmittance can be applied only for films with the thicknesses smaller than the absorption depth. Such kind of measurements cannot be realized with a relatively thick metal layer on the porous opaque substrate.The characterization of the cross section of...

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“…A comparison of the ϵ 1 and ϵ 2 as obtained here for Cu with values derived from reflection electron energy loss spectroscopy by Werner et al ., Hajati et al ., and by optical means by Johnson and Christy, Brimhal et al ., and Hagemann et al . The insert shows the low‐energy region on an expanded scale.…”

Section: Resultsmentioning

confidence: 99%

Extracting the dielectric function from high‐energy REELS measurements

Vos

Grande

2017

Surface & Interface Analysis

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A method is described for extracting the dielectric function directly from a reflection electron energy loss spectrum taken at relatively high energies (2.5 to 40 keV). It makes simplifying assumptions on separation of surface and bulk losses. The approach uses a description based on partial intensities and surface excitation parameters and fits directly the reflection electron energy loss data. Several different model dielectric functions are implemented (extended Drude, Drude Lindhard, Mermin, and the Levine-Louie dielectric functions with relaxation time), and their advantages and disadvantages are discussed. Justification of this approach is in the end based on a comparison with the dielectric function as obtained by other means, which is generally quite good, provided that the solution obtained is restrained by sum rules to the right refractive index and electron density. The fitting program, to be used in conjunction with commercial plotting software, is provided.

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Measured optical constants of copper from 10 nm to 35 nm

Cited by 21 publications

References 18 publications

Characterization of optical constants for uranium from 10 to 47 nm

Characterization of optical constants for uranium from 10 to 47 nm

Colour-Difference Measurement Method for Evaluation of Quality of Electrolessly Deposited Copper on Polymer after Laser-Induced Selective Activation

Extracting the dielectric function from high‐energy REELS measurements

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