Picosecond laser writing of highly conductive copper micro-contacts from deep eutectic solvents

Шестаков, Д. С.; Khairullina, Evgeniia M.; Shishov, Andrey; Khubezhov, Soslan A.; Makarov, Sergey; Tumkin, Ilya I.; Logunov, Lev

doi:10.1016/j.optlastec.2023.109777

Cited by 5 publications

(4 citation statements)

References 47 publications

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“…Previous work [22] has shown, in connection with the presence of large agglomerates in the PC, that a homogeneous surface is urgently required in order to produce reproducible, homogeneous and defect-free Cu structures. Shestakov et al also showed in the context of RLS with deep eutectic solvents that the layer thickness of the PC has a significant influence on the laser-generated Cu structure [30]. Accordingly, it is essential to adapt the viscoelastic behavior of the CuO-based RLS PC to the coating in order to minimize the presence of disturbances in the resulting layers.…”

Section: Discussionmentioning

confidence: 99%

Rheological Investigation of Highly Filled Copper(II) Oxide Nanosuspensions to Optimize Precursor Particle Content in Reductive Laser-Sintering

Bischoff,

Mücke,

Schubert

et al. 2024

Liquids

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In this article, the particle concentration of finely dispersed copper(II) oxide nanosuspensions as precursors for reductive laser sintering (RLS) is optimized on the basis of rheological investigations. For this metallization process, a smooth, homogeneous and defect-free precursor layer is a prerequisite for adherent and reproducible copper structures. The knowledge of the rheological properties of an ink is crucial for the selection of a suitable coating technology as well as for the adjustment of the ink formulation. Different dilutions of the nanosuspension were examined for their rheological behavior by recording flow curves. A strong shear thinning behavior was found and the viscosity decreases exponentially with increasing dilution. The viscoelastic behavior was investigated by a simulated doctor blade coating process using three-interval thixotropy tests. An overshoot in viscosity is observed, which decreases with increasing thinning of the precursor. As a comparison to these results, doctor blade coating of planar glass and polymer substrates was performed to prepare precursor layers for reductive laser sintering. Surface morphology measurements of the resulting coatings using laser scanning microscopy and rheological tests show that homogeneous precursor layers with constant thickness can be produced at a particle–solvent ratio of 1.33. A too-high particle content results in an irregular coating layer with deep grooves and a peak-to-valley height Sz of up to 7.8 μm. Precise dilution control allows the fabrication of smooth surfaces with a Sz down to 1.5 μm.

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Section: Discussionmentioning

confidence: 99%

Rheological Investigation of Highly Filled Copper(II) Oxide Nanosuspensions to Optimize Precursor Particle Content in Reductive Laser-Sintering

Bischoff,

Mücke,

Schubert

et al. 2024

Liquids

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“…In this regard, DLW has provided increased degrees of freedom for the seamless integration of these components, by allowing for the writing of several highly conductive materials, appropriate for low-power electronics integration, in several platforms, from rigid carriers to flexible substrates. In this regard, DLW processing of metal tracks has been the main approach, targeting useful metallic conductors such as copper, [75,137,169,196,199,246] silver, [35,42,101,118,163,336] platinum, [42] and liquid metals. [194,207,373] Has detailed in previous sections, attainable resolutions using these materials depend on several factors, including precursor formulations (e.g.…”

Section: Circuit Interconnectsmentioning

confidence: 99%

Direct Laser Writing: From Materials Synthesis and Conversion to Electronic Device Processing

Pinheiro,

Morais,

Silvestre

et al. 2024

Advanced Materials

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Direct Laser Writing (DLW) has been increasingly selected as a microfabrication route for efficient, cost‐effective, high‐resolution material synthesis and conversion. Concurrently, lasers participate in the patterning and assembly of functional geometries in several fields of application, of which electronics stand out. In this review, we survey and outline recent advances and strategies based on DLW for electronics microfabrication, based on laser material growth strategies. First, we summarize the main DLW parameters influencing material synthesis and transformation mechanisms, aimed at selective, tailored writing of conductive and semiconducting materials. Additive and transformative DLW processing mechanisms are discussed, to open space to explore several categories of materials directly synthesized or transformed for electronics microfabrication. These include metallic conductors, metal oxides, transition metal chalcogenides and carbides, laser‐induced graphene, and their mixtures. By accessing a wide range of material types, DLW‐based electronic applications are explored, including processing components, energy harvesting and storage, sensing, and bioelectronics. The expanded capability of lasers to participate in multiple fabrication steps at different implementation levels, from material engineering to device processing, indicates their future applicability to next‐generation electronics, where more accessible, green microfabrication approaches integrate lasers as comprehensive tools.This article is protected by copyright. All rights reserved

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“…Further research on this aspect is needed, regarding the exact formulation of the PC, as well as an adjustment of the laser and process parameters to RLS with CuO PC. In addition, it has been shown, in the context of other PC types, that the thickness of the PC also has an influence on the resulting electrical resistance [58]. To date, no consistent determination of an ideal particle size and shape for CuO-based RLS has been made.…”

Section: Reductive Laser Sintering With the Milled Precursormentioning

confidence: 99%

Preparation of Dispersed Copper(II) Oxide Nanosuspensions as Precursor for Femtosecond Reductive Laser Sintering by High-Energy Ball Milling

Bischoff,

Esen,

Hellmann

2023

Nanomaterials

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This contribution demonstrates and discusses the preparation of finely dispersed copper(II) oxide nanosuspensions as precursors for reductive laser sintering (RLS). Since the presence of agglomerates interferes with the various RLS sub-processes, fine dispersion is required, and oversized particles must be identified by a measurement methodology. Aside from the established method of scanning electron microscopy for imaging individual dried particles, this work applies the holistic and statistically more significant laser diffraction in combination with dynamic image analysis in wet dispersion. In addition to direct ultrasonic homogenization, high-energy ball milling is introduced for RLS, to produce stable nanosuspensions with a high fine fraction, and, above all, the absence of oversize particles. Whereas ultrasonic dispersion stagnates at particle sizes between 500 nm and 20 μm, even after 8 h, milled suspension contains a high proportion of finest particles with diameters below 100 nm, no agglomerates larger than 1 μm and a trimodal particle size distribution with the median at 50 nm already, after 100 min of milling. The precursor layers produced by doctor blade coating are examined for their quality by laser scanning microscopy. The surface roughness of such a dry film can be reduced from 1.26 μm to 88 nm by milling. Finally, the novel precursor is used for femtosecond RLS, to produce homogeneous, high-quality copper layers with a sheet resistance of 0.28Ω/sq and a copper mass concentration of 94.2%.

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Picosecond laser writing of highly conductive copper micro-contacts from deep eutectic solvents

Cited by 5 publications

References 47 publications

Rheological Investigation of Highly Filled Copper(II) Oxide Nanosuspensions to Optimize Precursor Particle Content in Reductive Laser-Sintering

Rheological Investigation of Highly Filled Copper(II) Oxide Nanosuspensions to Optimize Precursor Particle Content in Reductive Laser-Sintering

Direct Laser Writing: From Materials Synthesis and Conversion to Electronic Device Processing

Preparation of Dispersed Copper(II) Oxide Nanosuspensions as Precursor for Femtosecond Reductive Laser Sintering by High-Energy Ball Milling

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