This paper describes an in-line process for the realization of 3D electronic components on A4 format substrate by piezo inkjet printing. This process is developed within a semi-industrial prototype system named “JETPAC”. JETPAC includes an oxygen plasma torch for surface preparation and post-process modules as a variable frequency microwave oven and an UV lamp for metal selective sintering and dielectric ink curing, respectively. JETPAC is used to achieve passive components by chaining conductor and dielectric layers on kapton® substrate: silver nanoparticles based ink is used to print conductors. For multilayer component elaboration, the metal ink is deposited both on kapton® and on printed dielectric materials. Due to a low surface energy (S.E) of the printed dielectric, the realization of efficient silver tracks is compromised. A special process combines O2 plasma treatment and UV exposure before printing, allowing the reaching of S.E. value on dielectric near the optimum one (55mN/m). This pre-process allows printing of well-defined conductive structures on top of the dielectric. In-line sintering of printed structures is then performed using variable frequency microwave source. The process allows the elaboration of multilayer structures including stacked resistors and capacitors. These results make the developed process very promising for the realization by inkjet printing of passive devices for smart tag applications.

Microcontact printing is a versatile patterning technique, but is often limited by deformation of the stamp pattern. This paper examines the sensitivity of stamp pressure distributions to variations in displacement when the microcontact printing stamp is mounted on a rigid roll. To this end, we examine analytic and numeric solutions to the contact problem and verify our models with experimental data. Using these results, we provide insight to process limits imposed by dimensional errors in the printing system.

A photo-oxidized thin film, which transformed the organic silicone oil into inorganic glass, was coated on optical materials surface by using Xe2 excimer lamp at room temperature. This technique has enabled an optical thin coating capable of transmitting ultraviolet rays [UV] of wavelengths under 200 nm and possessing the characteristics of hardness, strain-free, resistance to high power laser, and resistance to water. UV and IR spectroscopic analysis was carried out for investigation of the oxidized silicone oil. The results revealed that the absorption peak of the CH3 group at 2900 cm-1 decreased as the irradiation time of the excimer lamp increased, and the transmittance of the light in the 172 nm wavelengths conversely became high. The UV transmittance of the silicone oil was 29.2 % before the lamp irradiation; and it improved to 90.6 % after the irradiation for 120 minutes. Moreover, in order to evaluate for resistance to laser damage [J/cm2/10 ns], the films were further irradiated with the Nd: YAG laser of ω [1.06 μm] or 2ω [0.503 μm]. The silica glass substrate had almost same laser tolerance in ω and 2ω, 112 J/cm2 and 113 J/cm2, respectively. The laser damage threshold of the photo-oxidized 100 nm thick film formed on the fused silica substrate was 72 J/cm2 in ω and 107 J/cm2 in 2ω.

We reported continuous depositions of grahene films on copper foils with A4 width using roll-to-toll microwave plasma chemical vapor deposition (MWPCVD) technique. A pair of winder and unwinder was built into an MWPCVD apparatus. Surface-wave plasma enabled us to deposit large-area graphene film (substrate stage is of 480 mm x 300 mm) at temperatures below 400 ºC. In Raman spectra, G- and G’-band attributed to graphene were obtained. In addition, Dand D’-band originated from defects and/or edges were detected. These results suggested that the obtained graphene films consisted of flake boundaries and defects. After the transferring graphene onto the polyethylene terephthalate film, uniform transmittance and sheet resistance were confirmed.

An electric insulation resistant coating has been developed by using photo-oxidized silicone oil. The silicone oil was exposed to ultraviolet⊈light in the air; which transformed the organic silicone oil into an inorganic amorphous glass film. Conventional large-area solar panels and smart papers are made of glass or plastic; in addition to being well insulated, waterproof, transparent, and hard, the panels are desirable to be light in weight and flexible. Here, metal foil is dipped into dimethylsiloxane silicone oil, and the silicone oil on the foil surface is irradiated with Xe2 excimer lamplight. Oxygen adsorbed on the sample surface is photo-excited by the irradiation to produce active oxygen. This active oxygen reacts with the silicone oil photo-excited and forms inorganic glass. With the process of the photo-oxidation, the silicone oil is vitrified, being inorganic.

In this paper we introduce a novel, flexible, system for mechanical deformation detection. The core of the system is based on an Organic Thin Film Transistor (OTFT) which has been assembled on a flexible PET substrate and patterned by means of inkjet printing. OTFT-based mechanical sensors were fabricated employing two different organic semiconductors, namely a small molecule (pentacene) deposited by thermal evaporation and its solution-processable derivative 6,13-bis(triisopropylsilylethynyl)-pentacene (TIPS-pentacene) deposited by drop casting. It will be shown that the surface deformation induced by an external mechanical stimulus gives rise in both cases to a marked, reproducible and reversible (within a certain rage of surface deformation) variation of the device output current. Starting from these results, more complex structures such as arrays and matrices of OTFT-based mechanical sensors have been fabricated by means of inkjet printing. Thanks to the flexibility of the introduced structure, we will show that the presented system can be transferred on different surfaces (hard and soft) and employed for a wide range of applications. In particular, we have designed and fabricated a fully functional system based on a matrix of 64 elements that can be employed for detecting mechanical stimuli over larger areas, and will demonstrate that such a system can be successfully employed for tactile transduction in the realization of artificial “robot skins”.

This study examined surface modification of solder resist and dry film resist using 60 Hz nonequilibrium atmospheric pressure plasma with O2/N2 mixing gas. Results show that the plasma discharge condition at O2/N2 mixing ratio of 0.1% was the best for surface modification for both materials, and the surfaces were modified sufficiently at 0.45 m/min package substrate transportation speed. From the plasma diagnostics by Vacuum Ultraviolet Absorption Spectroscopy (VUVAS) and Optical Emission Spectroscopy (OES), it was found that the behaviors of the oxygen radical density and NO-γ emission intensity correlate strongly with surface modification. The extremely high oxygen radical density around 4.7 × 1013 cm-3 was obtained at O2/N2 mixing ratio of 0.1%. The electron density was 2.5 × 1015 cm-3 that is two digits more than that of the conventional atmospheric pressure plasma such as Dielectric Barrier Discharge (DBD). The solder resist surface with the plasma treatment was analyzed by X-ray Photoelectron Spectroscopy (XPS), and it was clarified that material surface was modified by hydrophilic group generation owing polymer chain oxidation with oxygen radical.

A novel method to make low-resistivity metal lines in assembled silicon (Si) integrated circuit (IC) chips or other semiconductor chips with high-speed and low-cost is demonstrated. In the method, functional silver (Ag)-liquid (Ag-ink) which contains Ag nanoparticles (NPs) in organic solution is used to draw metal-lines in trenches formed on a plastic substrate by imprint technology. Surface energy of trenches is modified by exposing the substrate to ultra-violet (UV) light with the purpose of concentrating the functional Ag-ink into trenches by capillary effect in order to connect with electrodes of Si chips. The resistivity of such metal-lines can be lowered to 4×10-6 Ωcm by exposing the Ag metal-lines to hydrogen (H) atoms generated by catalytic cracking reaction with a heated tungsten catalyzer. X-ray photoelectron spectroscopy (XPS) proves that H atoms can remove organic compounds surrounding Ag NPs, resulting in the low-temperature sintering of NPs as confirmed by scanning electron microscopy (SEM). The method is promising for low-cost fabricating of IC cards or other electronic devices utilizing assemble of many semiconductor chips.