In this study, we propose a plating bath for electroless nickel-phosphorous (Ni–P) simultaneous deposition on both surfaces of a flexible polyethylene terephthalate (PET) substrate coated on one side with indium tin oxide (ITO). First a nucleation step is performed with tin(II) chloride and palladium(II) chloride. After this, a bath containing nickel ion source reducing agent, complexing and stabilization agents is used to deposit the Ni–P layer. The nucleation treatment used was the same for both ITO and PET surfaces, which results in a low-cost process compared to other methods. Several immersion times in the electroless bath were used to obtain the Ni–P layers onto PET and ITO surfaces. Structural, morphological and electrical properties of the samples were evaluated by optical microscopy, scanning electron microscopy, atomic force microscopy, energy dispersive spectroscopy, X-ray photoelectron spectroscopy, profilometry and four-point probe method. The Ni–P film deposition rate on the PET surface (112.2 nm/min) was higher than on the ITO surface (88.8 nm/min). The effect of the annealing temperature on the electrical and morphological properties of the Ni–P films were also investigated. After heat treatment (120 °C, 1 h), the Ni–P particles coalesced, resulting in more compact films, with reduced surface roughness, and with improved conductivity. Our approach enables an innovative dual function technological solution: the Ni–P/ITO side can be used as flexible current collectors in high-power output devices (e.g., emerging photovoltaic devices such as perovskite solar cells), whereas the PET side can be used for flexible current collectors in low-power output devices (e.g., sensors and capacitors). Both surfaces can be used concomitantly, combining the two kinds of application (e.g., integration of two types of electronic devices using a unique substrate).

The morphology and adhesion strength of the autocatalytic electroless nickel phosphorus (Ni-P) film, deposited at 40 ºC on polished alumina (Al2O3 99.6%) substrate, pretreated by sulfur/nitric solution, sensitizing with acid stannous chloride and activated using palladium chloride solutions, was studied using contact angle (CA), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), mechanical profilometer (DekTak), and direct laser writer (“maskless lithography”). The results showed that after treatment of the polished Al2O3 substrate, it presented a high performance in the electroless deposition of Ni-P thin-film at low temperature (40 ºC). It was obtained a more compact and continuous film, with small grain size and strong adherence.

The use of implantable devices for biomedical applications has been made possible by the ubiquity of vibration sensors and accelerometers, coupled with advances in microfabrication technologies. Among these devices, implantable auditory prostheses, such as hearing aids and cochlear implants, have emerged as a viable alternative to traditional external devices, which can cause discomfort to users. To meet the requirements for implantable auditory devices, a piezoelectric microelectromechanical systems (MEMS) accelerometer has been developed, which includes an AlN (Aluminun Nitrate) piezoelectric signal generator attached to a silicon proof mass. This paper presents the fabrication route developed at the Assembly, Packaging and System Integration Division from Renato Archer Center for Information Technology (DIMES/CTI), including anisotropic etching of silicon cavities, flip chip assembly and signal extraction routes, to seal a silicon proof mass sample (accelerometer) fabricated by a third party.

In this paper, a pre-treatment process for electroless copper (Cu) deposition on the polished alumina (Al2O3) 99.9% and the behavior of Cu plating by electroless process after Al2O3 surface treatment were explored. Our work was carried out by changing the roughness of Al2O3 through micro-etching (coarsening), nucleation its surface by a two-step method (sensitization and activation) and electroless Cu plating deposited using non-commercial solution having formaldehyde as reducer, alkaline pH and operating temperature of 30 ºC. Contact angle system (CA), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), mechanical profilometer (DekTak XT) atomic force microscopy (AFM) and analysis by Gwyddion v2.27 software were used to evaluate the wet treatment and the morphology of the electroless deposition (ED) of Cu on the Al2O3 surface. The results show that the surface treatment of purity polished Al2O3 with 0.1% of vitreous materials present into the substrate surface, presents a high performance in ED film at low temperature (30 ºC), during the Cu deposition, obtaining more compact and uniform film, with small grain size, uniform thickness, and a high purity Cu metallic deposit.

An experimental investigation comparing the properties of plasma jets in dielectric barrier discharge (DBD) configurations using a powered electrode with and without a dielectric barrier, while keeping a second dielectric barrier over the grounded electrode, is reported in this work. For this purpose, two different power sources were used to produce the plasma jets, with one of them producing a pulsed high-voltage (HV) output and the other one producing a damped sine-wave HV output, which acts as a pulse-like power source. Measurements of plasma parameters were performed for both configurations using argon and helium as working gases. As a result, if the pulsed power source is used, significant differences were found in discharge power (P-dis) and rotational and vibrational temperatures (T-r and T-v, respectively) when switching from one configuration to the other. On the other hand, using the pulse-like HV, only the P-dis parameter presented significant differences when switching the electrode's configuration. For the pulsed source, it has been observed that despite the remarkable increase in Pdis when changing from the double barrier configuration to the single barrier one, the values obtained for T-r and T-v also increased, but not in the same proportion as the increase in P-dis, which suggests a nonlinear dependence between temperatures and discharge power in the plasma jet. As an example for application of plasmas in both configurations, tests in an attempt to remove copper films deposited on alumina substrates were performed and, as a result, there was significant material removal only when the powered electrode was in contact with the plasma. As a general conclusion, if higher power is really required for applications that do not involve in vivo targets, it is better to use this configuration.

A Multichip Module (MCM) is a structure consisting of several ICs (typically bare chips) interconnected on a common supporting substrate and packaged as a single device. In this packaging technology, gold (Au) thin films are used as interconnection tracks terminated by wire bonding process to the chips. Thus, the good quality of theses Au films (for interconnects purpose) is essential. The present work proposes a metallization sequence of high purity (99.9%) and polished Al2O3 substrates, with an autocatalytic (electroless) NiP thin film follow by an electrolytic Au film in order to improve the MCM interconnections quality. The results show NiP and Au films with good adhesion, low roughness, good thickness distribution and optimal electrical properties, which allows us to establish a methodology that guarantees the reproducibility and quality of the Au interconnections in MCM devices.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

This work discusses the parameters and characteristics required on the development of a scalable and reliable electrochemical sensor board for detecting 8-hydroxy-2′-deoxyguanosine (8-OHdG), an oxidative stress biomarker for diabetic nephropathy, cancer and Parkinson’s disease. We used Printed Circuit Board (PCB) technology to make a precise, low-cost bare sensor board. ZnO nanorods (NRs) and ZnO NRs: reduced graphene oxide (RGO) composites were used as a pathway for antibody immobilization on the working electrode (WE). The parameters and characteristics of the WE were controlled for enhancing the quality of the electrochemical sensor board. Thickness of the gold and the presence of ZnO NRs or their composite on the WE have influence on charge transference process and reproducibility of the sensor board. The amount of the antibody, and its incubation period are crucial to avoid saturation of the sites during immobilization step and reduce the cost of the sensor. Our ZnO NRs-based electrochemical sensor board showed high sensitivity and selectivity to 8-OHdG with detection capacity in the range of 0.001–5.00 ng.mL −1 . The successful application of our immunosensor to detect 8-OHdG in urine was evidenced.

Current trend on electronics seek devices with more functionalities integrated on a smaller footprint. Multi-chip module technology based on thin films deposition (MCM-D) is one enabling technology that can achieve such demand. In this paper authors present a technological sequence to fabricate inductors onto an MCM-D device that can be integrated with other passive components aiming for higher integration compared to PCB technologies and RFID and/or IoT devices. We found Q values for unlicensed ISM (industrial, scientific and medical applications) bands of the fabricated devices present specs similar to commercially available components.

The paper presents a technological solution for high frequency packaging platform evaluated up to 40 GHz. The main purpose of this development was to define an alternative hybrid technology that is more flexible and faster to prototype compared with thin film or multi chip module (MCM-D). The alternative technology also shows adequate performance for high bit rate solutions integrating optical and electronics blocks. This approach consists of a soft substrate (laminate material), plating processes (electroless Ni-P/Au, electrolytic Au) and lithography patterning. Ground coplanar waveguide was used for microwave structures with excellent ground planes connections due to easy via holes implementation. We present results of high frequency packaging of important RF blocks, such as integrated broadband bias-T, transimpedance amplifier ICs and silicon photonics optical modulators. The paper demonstrates a solution for high frequency hybridization that can be implemented with standard substrates, designed with any shape and with large numbers of metalized via holes and compatible with usual assembling techniques.

The paper presents a technological solution for high frequency packaging platform to at least 40 GHz. This approach is based on soft substrate processing. We present results of high frequency packaging of important building blocks, such as bias-T, transimpedance amplifiers. The paper demonstrates a solution for high-frequency hybridization that can be implemented with standard substrates.

This paper evaluates the development of Multi-Chip Module Deposited (MCM-D) technology using photosensitive benzocyclobutene (BCB) to produce passive devices. The polymer was used as the dielectric and Ni-P/Au was used as the conductor film. The resistors' sheet resistance was measured with both TLM and direct measurement while the measurements of the capacitors and inductors required the usage of a Vector Network Analyzer (VNA) and treatment of the obtained s-parameters matrix in order to extract the values of both the capacitances and inductances.

This work presents results of the Multi-Chip Module-Deposited technology built with thin film processes over a substrate of alumina and oxidized silicon that was used to micro-fabricate passive components (capacitors, resistors, inductors). Metal layers were deposited by sputtering, electrolytic and electroless techniques and benzocyclobutene was used as dielectric. Electrical characteristics of passive components and filters were evaluated indicating that the testchip and processes were effective to manufacture the devices.

Multi-Chip Modules enable combining different integrated circuits with passive components leading to advantages in size, performance and cost. This paper presents the design of a testchip which was planned to extend the characterization of the process parameters for the development of MCM-D technology. It was made using Virtuoso Cadence Software, with minimum dimension of 20 μm, resulting in four mask layers.

Polyvinylidene Fluoride (PVDF) is a very versatile polymer with enough potential to provide a great development in materials science and technology, due to its piezoelectricity, low energy surface, low cost, flexibility, mechanical and chemical resistances. For electrical applications, like piezoelectric sensors and actuators, for example, PVDF surface metallization is essential. This paper describes an alternative metallization method, called electroless nickel-phosphorus deposition (Ni-P), in PVDF films deposited on glass substrate with some geometric structures fabricated by Photolithography. After a wet pre-treatment to improve adherence, electroless contact layer is deposited over PVDF masked by photolithography, using the lift-off technique. This process combination is very versatile, simple and gives good results, related to the Ni-P adhesion on PVDF surface and to the pattern resolution of photolithographic structures. Chemical composition of the alloyed film were measured by SEM/EDS (Scanning Electron Microscopy - Energy Dispersive X-Ray Spectroscopy), the PVDF surface treatment was examined using Infrared Spectroscopy and the resolution of Ni-P deposition evaluated by the Scanning Electron Microscope. This work opens a possibility of a new metallization technique for PVDF piezoelectric devices.

This paper describes a thin film fabrication technique of planar metallic microstructure with geometries between 10 and 20μm on 96% alumina substrate. This technique integrates a microfabricated capacitive bridge and thermistor on the same substrate employing metal and vacuum deposition. The procedure showed good resolution using a substrate with medium grain size between 3-5μm and average peak to valley surface roughness (Ra) 0.1μm. The film adhesion was tested by soldering metallic wires on the capacitor electrodes. These structures can be used for thin film characterization. We also deposited an oxide thin film (TiO2:WO3) by using polymeric precursors method.

The results of an investigation of thin Ni and CoNiMnP films deposited by electroplating over polyurethane-acrylate flexible substrates are presented. To improve magnetic properties of the films, an electroplating process was carried out with assistance of a strong magnetic field (3900G). The evaluated film properties were coercivity, remanence, maximum energy product, adherence and film composition. Comparison between the magnetic properties of the samples has shown that Ni and CoNiMnP films are suitable for distinct areas of applications in micro-devices: vibrating diaphragms and micro-magnet machines, respectively.