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The purpose of this paper is to describe a novel method for the manufacture of aluminum rigid‐flex circuit assemblies without the use of solder.

The approach involves the use of an aluminum base material and the embedding of components, while avoiding the use of solder in the assembly process.

The new methods and proposed structures address the key manufacturing problems that have vexed users for many years, while simultaneously addressing the challenge of thermal management. They also offer the advantage of enhanced reliability by avoiding the need for high temperatures used in soldering.

While examples of the process and its benefits have been demonstrated, further work is ongoing to expand applicability.

The paper begins with an overview of previous work in this area and then moves on to what is currently being implemented via the new technology. A novel method is described for the creation of potentially more cost‐effective and reliable rigid flex assemblies, which would be suitable for use in a wide range of products, from consumer to high‐reliability automotive, military and aerospace.

The purpose of this paper is to provide a historical perspective and framework for appreciating the evolution of 3D interconnection technologies from past to present.

A literature and patent search was performed to find the origins of 3D interconnections to find and credit work that was performed in the early electronics industry which presaged the development of the current generation 3D solutions.

The origins of 3D interconnections have roots that date to the beginnings of electronic interconnections if the earlier solutions are viewed in proper perspective. For example, early telegraphy and telephony interconnections strung from pole to pole across large expanses of terrain were clearly 3D interconnections on a very macro scale but those solutions scaled down are not that dissimilar to what is being done today in some advanced interconnection technologies.

The pioneers of the electronics industry broke a trail which has been widened, paved and branched by all who have followed them. Granted that the branches have led to new high‐worth discoveries but acknowledging the past and taking instruction from it is important, even necessary, to assure that future developments do not continually “reinvent the wheel”.

The paper traces, in brief fashion, the history of 3D interconnections providing examples of solutions which predate some of the current generation solutions which appear, in some cases, quite similar to those developed or proposed nearly half century ago. Knowing the past is vital to understanding and shaping the future.

Solder has been the primary method of component attachment since the early days of radio. This tradition carries with it an overhead which becomes increasingly expensive as the degree of miniaturisation increases. Solderless interconnect methods, however, are often overlooked or unfairly discounted as unreliable. Surprisingly, solderless connections can be mechanically superior to and environmentally more robust than their soldered peers. This paper reviews various solderless interconnect techniques for surface mount applications and discusses their relative merits.

Tin‐lead solder has been the primary method for connecting electronic components to printed circuit boards since near the time of its inception. Over the last 60 years, solder has proven a viable assembly method over that time and there is a deep understanding of the technology won over years of practice. However, the European Union has banned the use of lead in electronic solder, based on the misguided assumption that lead in electronic solder represented a risk to human health. Aims to describe a new approach to manufacturing electronic assemblies without the use of solder.

The paper discusses how the new era of lead‐free solder has resulted in a host of new problems for the electronics industry, many of which had not been experienced when elemental lead was included in the solder alloy.

Electronics assembly technology literature is rife with articles and papers citing the problems or challenges of lead‐free assembly and proposing new or improved solutions or investigative tool to better unearth the problems of lead‐free. The new process has come to be known as the Occam process, named to honor the fourteenth century English philosopher and logician, William of Occam, whose rigorous thinking and arguments in favor of finding the simplest possible solution served as the inspiration and catalyst for the new approach.

The paper describes a new approach to manufacturing electronic assemblies without the use of solder.

As part of a global expansion programme, Alpha Metals have announced two senior personnel changes which will strengthen their sales operations both in the UK and in the USA.

Alpha Metals Ltd (UK) have announced the appointment of David Crimp to the position of General Manager. Having served the company for four years as Sales Manager, Mr Crimp now assumes complete responsibility for Alpha's entire UK operation. Prior to his appointment with Alpha Metals, he was employed by AMAX in both the UK and France.

This paper seeks to give an overview on the benefits and challenges of moulded interconnect devices‐technology and the use of flexible printed circuits (FPC) in electronics production.

Each process step was adapted to the boundary conditions of manufacturing three‐dimensional substrates and FPC. The substrate materials were examined under the specific requirements of electronics production with a special focus on the thermal stability of the materials and the adhesiveness of the metallization.

The use of thermoplastics as substrate materials for electronic devices offers high potential but new challenges, e.g. the higher coefficient of thermal expansion of thermoplastics, have to be taken into consideration as well. In most cases, standard machines for surface mount technology can be used with few modifications. Research has shown that even components with very fine pitches can be used successfully on alternative substrate materials.

The paper covers a selection of possible thermoplastic materials that can be used in electronics production. Depending on the requirements of the application and the operating environment other substrate materials open up a large variety of possible solutions.

The paper details the most promising thermoplastic materials for use in electronics production as rigid and FPC. Furthermore, it gives information about manufacturing guidelines for the production of three‐dimensional circuit carriers.

Polymer thick film (PTF) technology provides the lowest cost, cleanest and most efficient manufacturing method for producing flexible circuits. Non‐contact radio frequency (RF) smart cards and related information transaction devices, such as RFID tags, appear to be a good fit for PTF‐flex. Flip chip also seems well suited for these “contactless” RF transceiver products. Flip chip and PTF adhesive technologies are highly compatible and synergistic. All PTF SMT adhesives assembly methods are viable for flip chip. However, the merging of flip chip with PTF‐flex presents major challenges in design, materials and processing. This paper will compare assembly methods and discuss obstacles and solutions for state‐of‐the‐art flip chip on flex within the RFID product environment.

Discusses three simple and low‐cost flip chip assembly processes. First, flip chip on board using non‐conductive adhesive is evaluated. This process can give reasonable reliability and high assembly yield, when the parameters for epoxy placement and bonding are optimised. Second, the flip chip assembly process using reflowable no‐flow underfill is discussed. Because the underfill epoxy is already placed in the gap between the IC chip and the substrate before reflow, it is not easy to control the solder joints’ collapse and obtain the desired solder‐joint shapes and stand‐off distance during reflow. Finally, the stud bump bonding process is also discussed. It is not easy although possible to maintain the optimal dipping of the conductive adhesive, when the average height of the gold bumps is small. Some solutions for overcoming the above‐mentioned difficulties are presented in this paper.

This paper presents the methods and results of load, deflection and electrical contact resistance experiments for reliable electronic module design using fuzz button technology. Both beryllium copper (BeCu) and molybdenum (Mo) fuzz button contacts were examined, as a function of wire diameter, button diameter and button density.