School of Mechanical, Electrical and Manufacturing Engineering


circuit board

Electronics Manufacturing Research Group

The work of the Electronics Manufacturing Research Group is based around the challenges in the design, materials science and manufacture of electronics intensive products.

Key areas of interest include process physics, materials interactions and increasingly, the problems associated with where the physical properties of the product directly impacts on its performance.  

An evolving area of activity has been the development of the manufacturing, packaging and information technologies associated with the opportunities afforded by developments in low power electronics and sensors that together comprise embedded intelligence. This has seen the group expand into embedded systems, firmware and software design.  

The group also hosts the hub for the Engineering and Physical Sciences Research Council’s Innovative electronics Manufacturing Research Centre.

Links between product function/performance and manufacturing employing multiple simulation engines with implementation in the aerospace electronics supply chain

1.1 Complex, Low volume electronics Simulation (CLOVES), TSB, £182k

1.2 Electronics manufacturing process advancement towards high yields, TSB, £98k

1.3 DISCOVER: Design and Simulation of Complex Low Volume Electronics Production, EPSRC IeMRC, £356k

The UK is a world leader in design and manufacture of high value electronics for the large aerospace, medical and energy High Value Manufacturing growth sectors. This industry has an intrinsic low batch size, and although highly automated, suffers typically 35% failures when products are first fully tested at the end of production. The sector faces imminent challenges: introduction of new materials and technologies e.g. lead free solders and new electronic devices for which process and reliability data are incomplete; operation at higher temperatures where reliability data is not available and, existing "accelerated" lifetime testing is slow, so New Product Introduction timescales are too long.

These projects have created and subsequently evolved novel software tools to collate these new data for product design and shop floor process control, that are integrated with the overall manufacturing systems, from materials logistics planning systems through to in-line process control, and are capable of learning and future adaption. This project has produced such tools and also the essential new design data from test examples produced by the new generation of manufacturing equipment incorporating in-line feedback. Lifetime and reliability data will be produced for the new operating conditions using conventional and the new generation of test equipment incorporating in-line monitoring that provide early signals of failure. New physics of failure based models for reliable design will be produced, identifying key parameters and new simulation models of the manufacturing stages. This will use the process and test data to provide predictions of performance, and process control to improve production rates of fully functional products by an estimated 25%.

Design for Increased Yield, EPSRC IeMRC, £263k

The aim of the DIY project is to provide an integrated software Design for X toolkit for aerospace electronics manufacturing products applicable throughout the:

  • electronics manufacturing supply chain (i.e. bare board manufacture, assembly, end user applications) 
  • electronics product and process lifecycle (i.e. design, specification, analysis, manufacture, test, deploy, maintain, reuse) 

The toolkit will be based upon a number of integrated sources of knowledge. Partner design, manufacturing and operational rules will be sourced along with the determination of a suite of reduced order “physics of failure” models of the key electronics manufacturing processes. Data centric models will be derived from design and analysis of appropriate test vehicles and experiments encapsulating relevant design features, components, materials and processes as identified by the supply chain partners. Integration of these models will enhance the capability of the toolkit and support the not only the prediction of sources of quality and reliability issues but also a root cause analysis capability

Sustainable Manufacturing of Transparent Conducting Oxide (TCO) Inks and Thin Films, EPSRC, £2.87M

This project seeks to develop processes and resources towards sustainable and inexpensive high quality transparent conducting oxide (TCO) films (and printed tracks) on float glass, plastics and steel. In particular replacement materials for Indium Tin Oxide (ITO) and F-doped Tin Oxide (FTO). These materials are used in low-e window coatings (>£5B pa), computers, phones and PV devices. The current electronics market alone is worth in excess of £0.9 Trillion and every tablet PC uses ca 3g of tin. Indium is listed as a critical element- available in limited amounts often in unstable geopolitical areas. Tin metal has had the biggest rise in price of any metal consecutively in the last four years (valued at >£30K per ton) and indium is seen as one of the most difficult to source elements. In this project we will develop sustainable upscaled routes to TCO materials from precursors containing earth abundant elements (titanium, aluminium, zinc) with equivalent or better figures of merit to existing TCOs.

Our method uses Aerosol assisted (AA) CVD to develop large scale coatings and developing new manufacturing approach to printed TCOs using highly uniform nanoparticle dispersions. AACVD has not been upscaled- although the related Atmospheric pressure (AP) CVD is widely used industrially. APCVD was developed in the UK (Pilkington now NSG) for commercial window coating methods- and in the UK glass industry supports >5000 jobs in the supply chain. Our challenge is to take our known chemistry and develop the underpinning science to demonstrate scale up routes to large area coatings. This will include pilot scale AACVD, nanoparticle dispersions and inks. Common precursor sets will be utilized in all the techniques. Our focus will be to ensure that the UK maintains a world-leading capability in the manufacturing of and with sustainable TCOs. This will be achieved by delivering two new scale up pathways one based on AACVD- for large area coatings and inks and dispersions for automotive and PC use.

We will use known and sustainable metal containing precursors to deposit TCOs that do not involve rare elements (e.g. based on Ti, Zn, Al). Key issues will be (1) taking the existing aerosol assisted chemical vapour deposition (AACVD) process from small lab scale to a large pilot lab scale reactor (TRL3) and (2) developing a new approach to TCOs from transparent nanoparticle dispersions synthesized in a continuous hydrothermal flow systems (CHFS) reactor using an existing EPSRC funded pilot plant process (kg/h scale). Nano-dispersions will be formulated for use by the rest of the team, in jet and screen printing, advanced microwave processing and TCO application testing. Industry partners will provide engineering support, guidance on the aerosol transport issues, scale up and dynamic coating trials (Pilkington now NSG), jet and screen printing on glass (Xaar, Akzo Nobel, CPI) and use the TCO targets for Magnetron Sputtering of thin films on plastics (Teer Coatings). The two strands will be overseen by Life-cycle modelling and cost benefit analyses to take a holistic approach to the considerations of energy, materials consumption and waste and, in consultation with key stakeholders and policy makers, identify best approaches to making improvement or changes, e.g. accounting for environmental legislation in nanomaterials, waste disposal or recyclability of photovoltaics. We believe there is a real synergy of having two strands as they are linked by common scale up manufacturing issues and use similar process chemistries and precursors.

Microwave & Millimetre-Wave System-on-Substrate using Sacrificial Layers for Printed RF MEMS Components, EPSRC IeMRC, £491k

Microwave and millimetre-wave systems are used extensively in communications, radar, imaging and sensing applications. System-on-substrate (SoS) technology is an exciting new concept where bulky coaxial cables and rectangular waveguide interconnects are replaced by low loss transmission lines embedded into a multilayer substrate that incorporates a wide range of components and subsystems. The advantages of this approach are dramatically enhanced if Radiofrequency (RF) Microelectromechanical Systems (MEMS) can be integrated into the substrate. MEMS components have had an explosive impact on consumer products including the iPhone and Nintendo Wii motion-sensing devices. Currently these products are fabricated with expensive silicon technology. From a manufacturing cost perspective, it is a much more attractive proposition to be able to fabricate the RF MEMS components in ceramic or organic laminate technology – i.e. directly onto a printed circuit board. This would lead to a technology capable of being used to manufacture large-scale system-on-substrate designs for applications such as scanning antenna arrays and adaptive stealth materials for a range of applications at microwave and millimetre-wave frequencies. It is proposed that these novel embedded RF MEMS components can be fabricated by employing screen-printing and by developing novel techniques based on sacrificial layers which are removed in a controlled manner during firing. It is envisaged that an effective and manufacturable solution would have a significant impact on UK industry in the area.

Integrated optical and electronics interconnect, EPSRC IeMRC, £850k

Digital information, encoded onto light signals, is regularly sent down optical fibres over distances varying from a few metres to thousands of kilometres. Fibres have largely replaced traditional copper cables for high performance broadband communication for distances exceeding a metre, as they offer advantages such as lower cost, immunity to electrical interference and weight savings. In the highest speed computers for communication between the central processor arrays and the hard disc storage arrays, through data routing switches, there is now considerable interest in incorporating high speed "optical wiring", by means of plastic light-guides, within large, metre-scale, electrical printed circuit boards (PCBs) combining optical and electrical interconnections (OPCBs). These PCBs (backplanes) are widely used in the electronic cabinets or racks that form the heart of a variety of IT systems and incorporate connectors to allow other OPCBs to be attached at right angles.

This three-year research project has explored novel methods, compatible with traditional multilayer PCB manufacturing processes, for the manufacture of optical waveguides capable of operating at very high data rates within an optical layer laminated into the board. Several process routes are under investigation, each with different levels of risk and cost. The large team of universities and industrial collaborators will enable the preparation, evaluation and exploitation of these processes. In addition, research will consider the requirements of design through the modification of commercial computer aided design software.

Glass Substrates for High Density Electrical and Optical Interconnect, EPSRC IeMRC, £326k

The continual miniaturisation of electronic products combined with increased functionality is placing greater demand on manufacturers to utilise flip-chip technology to obtain good electrical performance from packages with low profile and high I/O count. In addition, the requirement to rapidly transfer large amounts of data, not only over long distances, but within a system without the delays of electrical connections, has increased the need for the integration of optical waveguides into backplanes and printed circuit boards (PCBs).

The concurrent demands of electrical and optical technologies have placed huge demands upon PCB manufacturers. For optical interconnect the integration of waveguides presents challenges in materials selection and compatibility with manufacturing processes, together with accurate component alignment. For flip chip assembly the production of matching substrates requires PCB manufacturers to work at feature sizes similar to those of the semiconductor industry and has led to difficulties in the production of significant volumes of high density substrates at low cost. At present, this represents a barrier to the widespread implementation of flip-chip and optoelectronics that is not only impacting consumer electronics, but is influencing the uptake of new technologies, including MEMS, that are important to the UK electronics industry. This is made all the more challenging when it is considered that these changes must take place within the context of other requirements such as the increasing use of electronics in harsh environments and environmental legislation (assembly with high temperature lead free solders, recyclability of electronics). Based on these demands, it may no longer be appropriate to incrementally improve the existing substrate technology and represents an opportunity to introduce new materials and processes into circuit board manufacture.

The aim of this research programme was to investigate the use of thin glass sheets as a material to manufacture multilayer substrates able to support high density electrical and optical interconnect. Such substrates may be suitable as full size PCBs or as chip carriers within multi-chip modules. The project used laser machining to form microvias of 50μm diameter in thin (50μm) glass that were subsequently metallised to form conductive tracks. By using glass, more accurate positioning of vias was possible: due to more predictable dimensional stability and the ability to optically “view” target capture pads and tracks on layers below the surface. The glass has enabled efficient transmission of light for optical interconnect and laser machining will be used to form structures that will either be filled with optical polymer materials, or will be metallised to form mirrors and waveguides.

Micro-interconnects Using Mono-sized Polymer Microspheres for Large Format High Resolution Sensor Packaging, EPSRC IeMRC, £168k

Challenges and bottlenecks remain in the endeavour to deliver ultra-fine pitch interconnects for μBGA and flip-chip devices. There are two major factors that are of particular concern in the acquisition of such future generation technologies: i) the complexity associated with the micro-scale deposition of materials, and ii) the achievement of acceptable yields. As for the assembly equipment, alignment and bonding processes will become extremely critical. While the demands on reducing the gap between silicon foundry and wafer level packaging have so far been delivered, through various concepts including System in Package and System on Package, the search continues for assembly processes that are capable of interconnects at a pitch close to 10 microns to meet current and future demands of highly functional semiconductor devices.

This project is to carry out a feasibility study to enable such finer pitch interconnects through the use of novel materials and processes. The proposed work will use monosized metal coated polymer based micro-spheres specially fabricated by Conpart, a Norwegian company, to achieve ultrafine pitch interconnects by replacing traditional solder joints. Due to the unique polymerisation process used to fabricate the particles, their size and the chemical and mechanical properties can be tailored, with extreme accuracy and reproducibility. This, combined with metal plating technology, makes these spheres ideal as conductive elements which have been widely used in the anisotropic conductive adhesives (ACAs) used in flat panel display assembly.

The extension of this technology to the direct replacement of solid solder balls in μBGA and flip-chip assembly is currently of great interest for increasing the compliancy of the interconnections as a route to improved product reliability under thermal fatigues and shock loading. This feasibility study will explore the possibility of creating interconnections with such mono-sized polymer spheres for applications that demand connection pitches as fine as 10 microns, such as in X-ray detectors.

Embedded enhanced RFID (RFIX) for printed circuit board manufacture and value life-cycle tracking (INBOARD), TSB, £484k

The INBOARD project developed technology for embedding enhanced functionality RFID-based monitoring and tracking capability into high-value printed circuit boards. This RF information exchange (RFIX) system has been of value to the aerospace, automotive and electronics industries. This "in-board"capability is highly innovative, offering complete monitoring and tracking through the manufacturing processes, commissioning and operational history. This information is collected through a variety of sources including read-write wireless and on-board sensors. The development of an advanced end-user interface has formed part of the project. The technology has also offered novel security features. A strong consortium consisting of end-users, PCB manufacturers and RTD organisations has delivered to this project ensuring industrial focus and a robust, rapid exploitation route is being explored.

ESPRIT with Pervasive Sensing (Programme Grant), EPSRC, £7.3M

Elite athletes walk a fine line between performance success and failure. Although regarded by the public as examples of ultimate fitness, in reality they often exhibit vital signs bordering on clinical pathology. Their physiological parameters challenge our notions of what we consider clinically normal, for, as individuals, athletes represent a unique model of human stress adaptation and often, sadly, mal-adaptation. Understanding this human variance may assist ultimately in understanding aspects of well being in the population at large, in the work place and during healthy exercise, as well as when undergoing lifestyle changes to overcome disease, age-related changes and chronic stress.

To maximise the potential of GB athletes and support the quest for gold at future World Championships, Summer and Winter Olympic and Paralympic Games, the UK's sports governing bodies and the UK sports governing bodies and research councils have identified the opportunity for engineering and physical science disciplines to support and interact with the sports community during training. Not only will this secure competitive advantage for UK athletes, it will also, of more general application, contribute understanding of the biology of athletic performance to gain insights, which will improve the health and wellbeing of the population at large.

The vision of ESPRIT is to position UK at the forefront of pervasive sensing in elite sports and promote its wider application in public life-long health, wellbeing and healthcare, whilst also addressing the EPSRC's key criteria for UK science and engineering research. The proposed programme represents a unique synergy of leading UK research in body sensor networks (BSN), biosensor design, sports performance monitoring and equipment design.

The provision of "ubiquitous" and "pervasive" monitoring of physical, physiological, and biochemical parameters in any environment and without activity restriction and behaviour modification is the primary motivation of BSN research. This has become a reality with the recent advances in sensor design, MEMS integration, and ultra-low power micro-processor and wireless technologies. Since its inception, BSN has advanced very rapidly internationally. The proposing team has already contributed to a range of novel, low cost, miniaturised wireless devices and prototypes for sports and healthcare.

Intelligent embedded components for enhanced supply chain observability and traceability: INTELLICO, TSB, £415k

This project will develop highly innovative ambient intelligence (AmI) software components to increase significantly the observability and traceability of systems, human operators (HO's) and environments within the automotive and electronics manufacturing supply chains, thereby leading to more effective control and monitoring throughout the product supply chain and operational lifecycle based upon higher levels of intelligence. This knowledge generation capability requires the deployment of a network of integrated, embedded (within the product and processes) Radio Frequency components and systems with robust, reliable sensors, autonomous operation, proactive reasoning, learning and social abilities (e.g. communication, co-operation, conflict resolution and negotiation). The objective of INTELLICO is to demonstrate a prototype generic network at automotive and electronics manufacturing end-users.

Adaptive Informatics for Intelligent Manufacturing (AI2M), EPSRC, £2.42M

The AI2M research cluster has brought together leading researchers and practitioners in high value manufacturing, information science, ICT, mathematical sciences and manufacturing services to address the needs for future globally competitive ICT-supported manufacturing practices and infrastructures. The cluster also leverages two distinct supply chains, automotive and aerospace and defence with associated ICT and manufacturing service providers.

UK manufacturing has to migrate towards supplying innovative, high quality, variable volume solutions to a global market. Low wage competition and reduced profit margins increase the difficulty of recovering the costs of early lifecycle phases (specification, design, analysis and setup) especially for lower volume products. "Right first time" production is a necessity to survive. In the automotive domain the relatively high volume market is crippled by increased complexity, quality and customer demands for variety. The high added-value, low volume defence and aerospace domains are also under pressure from: the spectrum of product and process complexity; the harsh manufacturing and operational environments and severe safety and legislative requirements. The future of UK manufacturing depends on supply chains being able to: remove defects generated throughout manufacturing; formalise and share product and process knowledge; optimise strategy based on resource utilisation, traceability and lifecycle performance monitoring and understand the implications of design features on manufacturing and operational performance as well as the impact of new materials, components and legislation (e.g. End of Life Vehicle) and the impact of the adoption of new technologies and business models. To pay dividends both in supply chain efficiencies, compliance and new business models, companies must capture and analyse a larger range of data, faster, at lower cost and manage it better than ever before.

The challenge of this project is therefore to develop an on-demand intelligent product lifecycle service system for increased yield for products and processes that can bridge the information gaps associated with inefficient supply chain integration and a lack of knowledge on product usage throughout lifecycles. Current commercial solutions are limited to "on-site" silos of information that are restricting UK manufacturing in terms of its ability to: optimise efficiency in materials, resource, energy utilisation; speed up innovation; improve the generation and exploitation of manufacturing intelligence; support supply chain collaboration throughout the product and process lifecycles, and enable new business models and technologies to be readily adopted (e.g. product service systems (PSS) supporting either product operation, usage or results oriented business models).

Knowledge Driven Configurable Manufacturing (KDCM), EPSRC, £2.41M

This research programme is attempting to create self-reconfiguring manufacturing systems that are based on intelligent and highly accurate models of manufacturing processes and the products being manufactured. The goal of the research is to enable a radical change in manufacturing effectiveness and sustainability.

The target type of manufacturing is component-based modular reconfigurable systems, i.e. systems that are built up of various elements and assembled together, in a similar fashion to building with 'lego'. This is a class of manufacturing system that is typically used in assembly and handling applications, where you tend to find families of modular machine components that can be reused and reconfigured as the product, and hence production processes change. Major applications for this are in the automotive and aerospace sectors. One example is in powertrain assembly, as seen in the UK at Ford. If the re-configurability of such production systems can be enhanced, Ford estimate that potential savings of over 30% in costs are achievable with a target of a 50% reduction in the time to build and commission such a system that typically costs £30 million per engine line. The realisation of this research has the potential to help enable the retention of high value engineering activity in the UK by improving the competiveness in the engineering of reconfigurable manufacturing systems.

The concepts of flexible and reconfigurable manufacturing systems are well established; however problems still exist in the effective, efficient, rapid, configuration of such flexible systems, particularly as lifecycle product changes occur, whether such changes are minor or more fundamental. Many flexible and reconfigurable system examples exist. However, most are designed intuitively and a systematic methodology is still lacking. Additionally, engineering this integration of product and processes is essential in a lifecycle context across the supply-chain, yet this remains largely unaddressed.

Virtual engineering also has a major role to play in that we can simulate production systems and products. However the effectiveness of such simulation design tools for reconfigurable systems remains poor. Such tools need to be able to encompass the full system lifetime and be able to replicate the functions of the production system exactly in the models. These models are key enablers for understanding what might happen throughout a production system's lifecycle and can drive better configuration of the modular manufacturing systems we aspire to create.

EPSRC Centre for Doctoral Training in Embedded Intelligence, EPSRC, £3.43M

This Centre for Doctoral Training in Embedded Intelligence, the first in the UK, addresses high priority areas for economic growth such as autonomous complex manufactured products and systems, functional materials with high performance systems, data-to-knowledge solutions (e.g. digital healthcare and digitally connected citizens), and engineering for industry, life and health, which are also key priorities for Horizon 2020, the new EU framework programme for research and innovation. Horizon 2020 explicitly spells out ICT and Manufacturing as key industrial technologies. Its remit fits the EPSRC priority areas of ICT for Manufacturing and Data to Knowledge, and has an impact on industrial sectors as diverse as logistics, metrology, food, automotive, oil & gas, chemistry, or robotics. In addition, our world (homes, transport, workplaces, supplies of food, utilities, leisure or healthcare) is constantly seeking for interactive technologies and enhanced functionalities, and we will rely on these graduates who can translate technologies for the end-user.

The uniqueness of this Centre resides on the capability to innovatively address a myriad of Embedded Intelligence challenges posed by technical needs ranging from the EI supply chain: the design stage, through manufacturing of embedded or on-bedded devices, to the software behind data collection, as well as integrative technologies, to finally the requirements from end-users. The thematic areas, discussed conjointly with industry during the preparation of this proposal, allow us also to recruit students from a vast range of educational backgrounds. A strong user pull defines the nature of the challenges that this CDT will tackle. The graduates who shall come to alleviate the shortage of skilled engineers and technologists in the field will be exposed to the following thematic areas:

  • Device design, specification of sensors and measurement devices (power scavenging, processing, wire & wireless communications, design for low power, condition monitoring);
  • Packaging & integration technologies (reliability and robustness, physical and soft integration of devices, sub-components and wider system environment);
  • Intelligent software (low level, embedded, system level, database integration, ontology interrogation, service oriented architectures, services design);
  • Manufacturing solutions (design for manufacture of embedded systems, advanced and hybrid manufacturing processes for embedding, process consolidation technologies, biomimetics and cradle-to-cradle for sustainability production, etc.);
  • Applications engineering (design and implementation of embedded technologies for in-time, in-line products, processes and supply chains; product and process design for embedded intelligence);
  • System Services: (i) Service Foundations (e.g., dynamically reconfigurable architectures, data and process integration and semantic enhanced service discovery); (ii) Service Composition (e.g. composability analyses, dynamic and adaptive processes, quality of service compositions, business driven compositions); (iii) Service Management and Monitoring (e.g. self: -configuring, -adapting, -healing, -optimising and -protecting) and (iv) Service Design and Development (e.g. engineering of business services, versioning and adaptivity, governance across supply chains).

Our flagship, the 'Transition Zone' training, will facilitate the transition into doctoral studies in the first year of studies, and, closer to the end of the programme, out to industry or self-employment. As employable high calibre individuals with a good understanding of enterprising, commercialisation of research, social responsibility, gender equality and diversity, innovation management, workplaces, leadership and management, our doctorates will grow prosperity bottom up, enjoying a wealthy network of academic and industrial contacts from their years at the CDT, as well as their peers at the Centre.