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The Geislingen research laboratories of Dr Ing. Max Schlötter have developed Slotoposit, a new and advanced process for the manufacture of high quality PTH circuits, using conventional subtractive techniques. The aim of the research was to remove the hazardous formaldehyde present in most electroless copper systems, to improve hole wall adhesion and process the boards in one plating operation rather than the two (panel and pattern) employed in the traditional system. The following paper describes how a stable electroless nickel has been developed to achieve these ends and to increase productivity significantly by reducing the process steps and times.

This study aims to elucidate the reaction mechanism of electroless NiP deposits on conductive but non-catalytic Cu films on the basis of their nucleation and growth without Pd catalyst and to measure the deposition rate and activation energy of electroless NiP deposits on the non-catalytic Cu film at various deposition times (60, 120, 240 and 480 s) and temperatures (70, 80 and 90°C) at pH 4.6.

Specimens with and without Pd catalyst on Cu film were prepared as follows: the Pd catalyst was deposited on half of the Cu film using a deposition protector, and the specimen containing the Pd catalyst deposited on half of its area was immersed in electroless NiP solution. The growth of NiP on the Cu films with and without the Pd catalyst was observed.

The number of Pd nanoparticles increased with Pd activation time; the nucleation of Pd dominated over growth at 60 s. Lattice images show that the d-spacing of Ni nanoparticles doped with less than 10 at% P increased to 2.050 Å. Nucleation of NiP deposits occurred simultaneously in the specimens with and without the Pd catalyst, because electrons could be transferred via the conductive Cu. Therefore, the reaction mechanism of the electroless NiP deposited on Cu film appears to be electrochemical. The activation energies for NiP deposits (15 s Pd with catalytic Pd, 15 s Pd without catalytic Pd, 60 s Pd with catalytic Pd and 60 s Pd without catalytic Pd) on the Cu film are 65.8, 64.0, 64.3 and 58.1 kJ/mol, respectively. This demonstrates that, regardless of the volume and the presence of catalytic Pd, the activation energy of electroless NiP has a consistent value.

It is necessary to study the relationship between the volume of Pd nanoparticles and the nucleation rate of NiP at an initial stage, as there are limited data regarding the effect of Pd volume on the nucleation rate of NiP.

The reaction mechanism of the electroless NiP deposited on conductive but non-catalytic Cu film involves electrochemical reactions because the nucleation of NiP deposits occurs on conductive Cu film regardless of the presence of the Pd catalyst.

The adhesion between electroless copper and a substrate is one of the most important factors in the reliability of thermoplastic printed circuit boards. The purpose of this paper is to investigate the effects of mechanical grinding and acid etching of thermoplastic substrate materials on the adhesion of copper deposited by an electroless copper plating process. The base material of the test substrates was a new high temperature thermoplastic polyphenylene oxide (PPO) compound.

The effects of pre‐treatment on plastic surfaces are analyzed by the following methods: Fourier transform infrared (FTIR), SEM, the Dyne surface energy test and the surface roughness test. The adhesion between electroless copper and thermoplastic substrate is measured with a peel strength test.

The results showed that mechanical grinding of the substrates significantly increased adhesion but the highest adhesion is gained by using an acid etch treatment before electroless plating. These results indicated that adhesion between copper and the substrates was not directly proportional to the roughness and surface energy values.

The conventional sweller/desmear treatment used in a printed circuit board factory for pre‐treating epoxy based laminates prior to electroless plating is not suitable for these PPO compound boards. The copper adhesion is adequate when the substrates are etched with sulphuric acid/chromate solution. In that case the bonding between the metal layer and the plastic surface is stronger than the bondings between the polymer chains of the thermoplastic material. The adhesion mechanism of electroless copper in these mechanically abraded samples is mechanical interlocking of metal particles.

This paper concerns a novel process for forming additive copper interconnect on flexible substrates via printing and plating processes. Building on the established conductive lithographic film and CLF plating seeding technologies, the described process enables low‐cost substitutes for existing flexible electronic wiring boards to be manufactured without precious metals.

Autojig Computer Aided Test software from Candela Automation Systems generates bare board test data from Gerber photoplot files. All the information required to test bare printed circuits is produced automatically.

The purpose of the current study is to explore the potential possibility of acceleration in recognition, remedial process of heart disease and continuous electrocardiogram (ECG) signal acquisition. The textile-based ECG electrode is prepared by inkjet printing of activator followed by electroless plating of nickel (Ni) particle.

The electrical resistance shows a range of around 0.1 Ω/sq, which sounds quite proper for ECG signal acquisition, as the potential difference according to heart activity on skin surface is in milivolt range. Surface modifications of Ni–phosphorus (P)-plated polyester fiber were studied by scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffractionmethods. The quality of the acquired signal from printed square-shaped sensors in two sizes with areas of 9 and 16 cm2 compared with the standard Ag/Agcl electrode using commercial ECG with the patient in the sitting position.

Comparison of these data led to the consideration of small fabric sensor for better performance and the least disturbance regarding homogeneity and attenuation in electric field scattering. Using these types of sensors in textile surface because of flexibility will provide more freedom of action to the user. Wearable ECG can be applied to solve the problems of the aging population, increasing demand for health services and lack of medical expert.

In the present research, a convenient, inexpensive and reproducible method for the patterning of Ni features on commercial polyester fabric was investigated. Printed designs with high electrical conductivity can be used as a cardiac receiving signals’ sensor.

Multicore Solders Ltd are pleased to announce that Jack Saw, Paul Salmon, Gordon Clarke and Tom Perrett have joined their commercial division. The decision of Billiton Solders, UK, to sell the assets of their profitable solder division to the Cookson group released the aforementioned personnel who will be pleased to maintain their contacts in the industry and offer the same personal service as is the Multicore tradition.

This paper describes a method for patterning fine line interconnections over non‐planar surfaces and introduces the idea of using holographic masks for more challenging geometries.

A photolithographic method for achieving grossly non‐planar interconnects is described. The patterning of electrical interconnections onto the piezo‐electric actuators of an ink‐jet print head is used as an example. Uniform coverage of the substrate is achieved using an electro‐depositable photoresist. The required pattern is transferred via a custom‐designed chrome‐on‐glass mask using a standard mask aligner.

Large arrays of 100 μm‐pitch electrical interconnections were successfully deposited onto 500 μm‐high high piezo‐electric actuators. It was necessary to modify the shapes of the line segments on the mask in order to compensate for diffractive line broadening. For more extreme 3D geometries it becomes necessary to consider the use of holographic masks.

Printed circuit boards and semiconductor wafers are nominally flat and traditional lithographic processes have been developed accordingly. However, future microelectronic packaging schemes and microsystems may require patterning to be achieved on grossly non‐planar surfaces. We have demonstrated that this can be achieved on ink‐jet print heads using photolithography and point to the research necessary to enable it to be realised on more extreme non‐planar substrates.

Dr Setty reports from ISHM‐India, who had their first committee meeting on the 4th October 1985, that the Society is now off the ground and that the Symposium on Hybrid Microelectronics held on February 5th attracted considerable interest, some 150 persons attending. Dr Sonde was the organising committee Chairman and was fortunate in being able to persuade the Department of Electrical Communication Engineering of the Indian Institute of Science in Bangalore, which has set up its thin and thick film hybrid department, to host this important event. Papers were given by visiting speakers from the US, UK and West Germany as well as from India itself. Among the presentations given were papers introducing some of the country's facilities from which it can be seen that microelectronics has an important future here.

Recently a number of new photographic systems have been investigated with the object of replacing the conventional silver halide emulsions and as such could possibly represent the basis for further development of new methods of production for printed circuits. By using prepared combinations of metal and a light sensitive substance, e.g., arsenous sulphide/silver and cadmium iodide/tin, one can obtain directly a positive metal image. This approach by the authors was used for the development of a new direct positive photographic material for printed circuits which is easily processed and can be safely stored.