Electrical Interconnects Research Articles

Multi-sensing yarns for continuous wireless sweat lactate monitoring

Textile integrated sensors based on conductive, electrochemically active microfibers can enable inexpensive, nearly invisible distributed sensing of sweat in clothing. Reduced graphene oxide fibers are mechanically robust, conductive, and can be easily functionalized to form a variety of sensors with properties comparable to planar fabricated sensors, given their ability to work both as electrical interconnections and as a base electrode. Here, we present an electrochemical yarn based on modified dry-spun reduced graphene oxide fibers. This braided format contains reference, counter electrode, a lactate-responsive fiber functionalized with lactate oxidase, and a pH-sensing fiber for calibration in a single, robust, weavable format. This electrochemical yarn was integrated into a demonstrator wearable textile-patch capable of continuous data collection and wireless data transmitted to an ad-hoc app. The yarns perform comparably to traditional probes in a format of broad utility for standalone or integrated monitoring of physiological parameters.

Flexible and Extensible Ribbon-Cable Interconnects for Implantable Electrical Neural Interfaces.

The design and characterization of thin-film ribbon cables as electrical interconnects for implanted neural stimulation and recording devices are reported. Our goal is to develop flexible and extensible ribbon cables that integrate with thin-film, cortical penetrating microelectrode arrays (MEAs). Amorphous silicon carbide (a-SiC) and polyimide were employed as the structural elements of the ribbon cables and multilayer titanium/gold thin films as electrical traces. Using photolithography and thin-film processing, ribbon cables with linear and serpentine electrical traces were investigated. A cable design with an open lattice geometry was also investigated as a means of achieving high levels of extensibility while preserving the electrical function of the cables. Multichannel ribbon cables were fabricated with 50 mm lengths and metallization trace widths of 2-12 μm. The ribbon cables tolerate flexural bending to a radius of 50 μm with no change in trace impedance but tolerate less than 5% tensile elongation without trace failure. Ribbon cables with a lattice structure exhibit 300% elongation without failure. The high elongation tolerance is attributed to a lattice design that results in an out-of-plane displacement that avoids fracture or plastic deformation. Extensible ribbon cables underwent up to 50,000 tensile elongation cycles to 45% extension without failure. An electrical interconnect process using through-holes in the distal gold bond pads of the ribbon cables was used to connect to an a-SiC-based MEA. The electrical connection was created by stenciling a conductive epoxy into the through-holes, bridging metallization between the traces, and MEA. The interconnect was tested using a ribbon cable connected to an a-SiC MEA implanted acutely in rat cortex and used to record neuronal activity. These highly flexible and extensible ribbon cables are expected to accommodate large extensions and facilitate cable routing during surgical implantation. They may also reduce tethering forces on implanted electrode arrays, potentially improving chronic neural recording performance.

Trend Analysis of Cross-Border Electricity Trading in Pan-European Network

The long-term global target of facilitating energy security and optimizing resource utilization while supporting the transition to sustainable energy systems has led the pathway towards regional cooperation in the context of energy infrastructures and trading. Recent trends highlight the development of transnational energy grids, pipelines, and renewable energy projects, facilitating efficient distribution of electricity, gas, and other energy forms. These advancements offer benefits such as increased reliability of energy supply, cost savings through shared resources, and strengthened relationships between countries. However, challenges persist, including regulatory differences, geopolitical tensions, alignment of market rules as well as substantial investment requirements in infrastructure and technology. Addressing these challenges necessitates harmonized policies, robust legal frameworks, and cooperative international governance, which are crucial for effective cross-border energy trading. The aim of the work is to present the current landscape as well as analyze the latest trends and developments in the dynamic field of electricity interconnectors, providing insights into its trajectory and implications for the European internal energy market.

Aerosol Jet and Inkjet Printing Methods for Die-Level Packaging of Custom MEMS Devices

Abstract In this study, we propose an alternative, low-cost, packaging method using both inkjet and aerosol jet printing to fabricate functional interconnects for custom die-level packages assembled on Printed Circuit Boards (PCB). Our process involves the manufacturing of a stacked structure with insulating and conducting layers, fabricated using inkjet and aerosol jet printing, respectively. In the first part of the study, we characterized UV adhesive deposition on the standard resin-coated PCB to acquire the optimal parameters necessary for the fabrication of the insulating layer with thicknesses around 100 μm. In the second part of our study, we developed a precise method for printing silver conducting lines using an aerosol jet printer, enabling the realization of structures with features as small as 50 microns on non-planar surfaces. The insulating part of the MEMS/PCB structure serves as a ramp ensuring continuity of the aerosol jet printed connection between the PCB and the Si die. A 1 cm x 1 cm Si chip with a custom MEMS microrobot was used to demonstrate the feasibility and flexibility of our approach in practice. After fabrication, we evaluated the interconnects for conductivity and repeatability. The packaging and inspection process was carried out using Nexus, a unique robotic system integrating additive manufacturing, robotic transport, and metrology. The results show that we successfully fabricated printed interconnects between copper PCB pads and Si die cleanroom fabricated gold pads, while electrical characterization revealed resistances in the range of 1 Ω - 10 Ω. Our approach can be utilized in the manufacturing of electrical interconnects for custom devices on different substrates, including traditional and flexible PCBs. Furthermore, the applied printing techniques enable the use of other insulating or conducting inks and the formation of structures of custom geometries across a wide range of scales - 20 μm to 1 mm.

The e-Flower: A hydrogel-actuated 3D MEA for brain spheroid electrophysiology.

Traditional microelectrode arrays (MEAs) are limited to measuring electrophysiological activity in two dimensions, failing to capture the complexity of three-dimensional (3D) tissues such as neural organoids and spheroids. Here, we introduce a flower-shaped MEA (e-Flower) that can envelop submillimeter brain spheroids following actuation by the sole addition of the cell culture medium. Inspired by soft microgrippers, its actuation mechanism leverages the swelling properties of a polyacrylic acid hydrogel grafted to a polyimide substrate hosting the electrical interconnects. Compatible with standard electrophysiology recording systems, the e-Flower does not require additional equipment or solvents and is ready to use with preformed 3D tissues. We designed an e-Flower achieving a curvature as low as 300 micrometers within minutes, a value tunable by the choice of reswelling media and hydrogel cross-linker concentration. Furthermore, we demonstrate the ability of the e-Flower to detect spontaneous neural activity across the spheroid surface, demonstrating its potential for comprehensive neural signal recording.

Recent Developments in Low Temperature Wafer Level Metal Bonding for Heterogenous Integration

Abstract An overview of various low-temperature (<200°C) wafer bonding processes using metal interlayers is presented. Such processes are very attractive for novel applications in 3D heterogenous packaging as the allow for simultaneous formation of electrical interconnects, as well as hermetic encapsulation of various sensors and microelectromechanical systems-based devices. Metal wafer bonding is a generic category of processes consisting of various sub-categories, each one defined by the different principles governing the process. One can differentiate between eutectic wafer bonding (a eutectic alloy is formed as bonding layer during the process by liquid-solid interdiffusion), intermetallic wafer bonding (an intermetallic alloy is formed as bonding layer during the process by solid-liquid interdiffusion, a process known also as solid liquid intermetallic diffusion transient liquid phase, and metal thermo-compression wafer bonding. Different critical/gating parameters were investigated and their impact for generally reducing processing temperatures for the different metal bonding systems was studied.

Investigation of Optical Interconnects for nano-scale VLSI applications

The relentless trend toward miniaturization has brought interconnects to the brink of communication bottlenecks, operating at or near their ampacity (current carrying capacity) limits. This degradation in performance necessitates novel technologies with increased ampacity. This study explores optical interconnect (OI) as a potential future technology, offering high-bandwidth communication and low latency. This study models and simulates OI, integrating recent optical device advancements with modest modulator and detector capacitance (50 fF). Performance metrics including signal delay, power dissipation, and power-delay-product (PDP) are compared across copper (Cu) and single-wall carbon nanotube bundle (SWCNT-B) interconnects at 22 nm and 14 nm technology nodes. Results consistently show OI, with an active voltage current feedback (AVCF) based regulated gain cascode (RGC) transimpedance amplifier (TIA) receiver, outperforms Cu and SWCNT-B interconnects at global lengths and beyond. For instance, at 1000 μm and 22 nm, OI exhibits 88.47 % and 62.15 % delay improvements over Cu and SWCNT-B, respectively. This trend persists at 14 nm, with OI showing 93.68 % and 84.29 % delay improvements, respectively. Additionally, OI surpasses Cu and SWCNT-B in power efficiency beyond a critical length. As interconnects extend to global scales and beyond, the differences in delay, power, and PDP between OI and electrical interconnect increases, highlighting OI's advantages for future VLSI IC applications.

On chip control and detection of complex SPP and waveguide modes based on plasmonic interconnect circuits

Abstract Optical interconnects, leveraging surface plasmon modes, are revolutionizing high-performance computing and AI, overcoming the limitations of electrical interconnects in speed, energy efficiency, and miniaturization. These nanoscale photonic circuits integrate on-chip light manipulation and signal conversion, marking significant advancements in optoelectronics and data processing efficiency. Here, we present a novel plasmonic interconnect circuit, by introducing refractive index matching layer, the device supports both pure SPP and different hybrid modes, allowing selective excitation and transmission based on light wavelength and polarization, followed by photocurrent conversion. We optimized the coupling gratings to fine-tune transmission modes around specific near-infrared wavelengths for effective electrical detection. Simulation results align with experimental data, confirming the device’s ability to detect complex optical modes. This advancement broadens the applications of plasmonic interconnects in high-speed, compact optoelectronic and sensor technologies, enabling more versatile nanoscale optical signal processing and transmission.

Unconventional magnetoresistance and resistivity scaling in amorphous CoSi thin films

The resistivity scaling of Cu electrical interconnects represents a critical challenge in Si CMOS technology. As interconnect dimensions reach below 10 nm, Cu resistivity increases significantly due to surface scattering. Topological materials have been considered for application in ultra-scaled interconnects (below 5 nm), due to their topologically protected surface states that have reduced electron scattering. Recent theoretical work on the topological chiral semimetal CoSi suggests that this material could offer lower resistivity than Cu at dimensions smaller than 10 nm. Here we investigate the scaling trend of textured and amorphous CoSi thin films, deposited by molecular beam epitaxy in a thickness range between 2 and 82.5 nm. Contrary to predictions of standard resistivity models, we report here a reduction in resistivity for thin amorphous CoSi films, which is instead consistent with surface-dominated transport. Moreover, magnetotransport measurements reveal significant enhancement of the magnetoresistance in scaled films, highlighting the complex transport mechanisms present in these highly disordered films at thicknesses of a few nanometers.

Abatement of ionizing radiation for superconducting quantum devices

Ionizing radiation has been shown to reduce the performance of superconducting quantum circuits. In this report, we evaluate the expected contributions of different sources of ambient radioactivity for typical superconducting qubit experiment platforms. Our assessment of radioactivity inside a typical cryostat highlights the importance of selecting appropriate materials for the experiment components nearest to qubit devices, such as packaging and electrical interconnects. We present a shallow underground facility (30-meter water equivalent) to reduce the flux of cosmic rays and a lead shielded cryostat to abate the naturally occurring radiogenic gamma-ray flux in the laboratory environment. We predict that superconducting qubit devices operated in this facility could experience a reduced rate of correlated multi-qubit errors by a factor of approximately 20 relative to the rate in a typical above-ground, unshielded facility. Finally, we outline overall design improvements that would be required to further reduce the residual ionizing radiation rate, down to the limit of current generation direct detection dark matter experiments.

Research on Multi-Microgrid Electricity–Carbon Collaborative Sharing and Benefit Allocation Based on Emergy Value and Carbon Trading

In response to climate change, the proportion of renewable energy penetration is increasing daily. However, there is a lack of flexible energy transfer mechanisms. The optimization effect of low-carbon economic dispatch in a single park is limited. In the context of the sharing economy, this study proposes a research method for multi-park electricity sharing and benefit allocation based on carbon credit trading. Firstly, a framework for multi-park system operation is constructed, and an energy hub model is established for the electrical, cooling, and heating interconnections with various energy conversions. Secondly, a park carbon emission reduction trading model is established based on the carbon credit mechanism, further forming an optimal economic and environmental dispatch strategy for multi-park electricity sharing. Matlab+Gurobi is used for solving. Then, based on asymmetric Nash bargaining, the comprehensive contribution rate of each park is calculated by considering their energy contribution and carbon emission reduction contribution, thereby achieving a fair distribution of cooperation benefits among multiple parks. The results show that the proposed method can effectively reduce the overall operational cost of multiple parks and decrease carbon emissions, and the benefit allocation strategy used is fair and reasonable, effectively motivating the construction of new energy in parks and encouraging active participation in cooperative operations by all parks.

Materials, Structure, and Interface of Stretchable Interconnects for Wearable Bioelectronics.

Since wearable technologies for telemedicine have emerged to tackle global health concerns, the demand for well-attested wearable healthcare devices with high user comfort also arises. Skin-wearables for health monitoring require mechanical flexibility and stretchability for not only high compatibility with the skin's dynamic nature but also a robust collection of fine health signals from within. Stretchable electrical interconnects, which determine the device's overall integrity, are one of the fundamental units being understated in wearable bioelectronics. In this review, a broad class of materials and engineering methodologies recently researched and developed are presented, and their respective attributes, limitations, and opportunities in designing stretchable interconnects for wearable bioelectronics are offered. Specifically, the electrical and mechanical characteristics of various materials (metals, polymers, carbons, and their composites) are highlighted, along with their compatibility with diverse geometric configurations. Detailed insights into fabrication techniques that are compatible with soft substrates are also provided. Importantly, successful examples of establishing reliable interfacial connections between soft and rigid elements using novel interconnects are reviewed. Lastly, some perspectives and prospects of remaining research challenges and potential pathways for practical utilization of interconnects in wearables are laid out.

Effect of Ni Addtion on Electroless Cu for High Density Interconnect PCB Substrate

Introduction Nowadays, high-density interconnect (HDI) printed circuit board (PCB) substrates have been widely applied to high-end electronics to meet the increasing input and output (I/O) density and small footprint area. Micro-via, a tiny structure buried among build-up layers that provide electrical interconnection is a key component in the HDI substrate. However, the preparation of micro-via is facing new challenges. It is not only required that the size of the micro-via scales down to meet the increased interconnect density, but also that the micro-via should withstand severe operating conditions in different scenarios. Therefore, it is of great importance to improve the quality of micro-vias during processing and manufacturing. The micro-via structure is a sandwich structure that is processed by electroless Cu plating and Cu electrolyte plating sequentially, and thus the quality of the electroless Cu layer can significantly affect the reliability of micro-via. In this work, we mainly focused on the electroless Cu plating process and investigated the effect of the electroless Cu deposition speed on the quality of the micro-via structure. SIM and HR-TEM characterizations were employed to investigate the micro-structure inside the electroless Cu layer. Materials and Method In this study, we used the common alkaline ion catalyst method to prepare the electroless Cu layer. The electroless Cu plating and electrolyte Cu plating was conducted on a PCB Resin Coated Copper (RCC) substrate that was cleaned by soft etching in an acid condition. The surface is then pre-dipped in an anionic solution, and palladium ions were adsorbed using an alkaline ion catalyst. The electroless Cu processes adopted in a reaction bath that consists of Cu resource (CuSO4·5H2O), complexing agent (KNaC4H4O6·4H2O) and reductant (HCHO). The whole reaction was conducted in the alkaline condition with a PH of 12.5, and the thickness of the electroless Cu deposition was controlled at around 0.20 µm. NiSO4 is selected as the Ni precursor to alter the Ni concentration in the reation bath. The contents of Ni addition were selected as 50 %, 100 %, 200 % and 300% of a conventional process at a bath temperature of 27 ºC. The thickness of the plated Cu layer was measured by a gravimetric method. Results and discussion TEM observation was used to identify the structure at the interface. Fig. 1 shows the TEM observation of the sample with 50 % and 200 % Ni concentrate. There are some nanovoids found at the interface between the Cu substrate and electroless Cu, which is arguably due to hydrogen generated during electroless Cu plating. The sample with a higher reaction speed has more nanovoids. It can be due to that the higher reaction speed can generate more hydrogen bubbles in the bath that can attach to the electroless Cu layer, leading to nanovoids as shown in Fig. 1. The samples prepared at different bath temperatures are under investigation to illustrate that the reaction speed can significantly affect the Cu electroless layer quality. Conclusions In this work, we investigated the Ni effect in electroless Cu on the RCC substrate. It is found that the higher Ni incorporation can lead to massive nanovoids generation and fine Cu grains in the electroless layer, which is a potential risk for the reliability of the HDI substrate. By reducing the Ni incorporation content, the number of nanovoids can be effectively reduced. Figure 1

An adaptive two-step staircase static reconfiguration method for improving the power generation of PV array

Partial shading of solar photovoltaic (PV) panels can significantly affect the performance of solar PV arrays. Various reconfiguration techniques have been explored in recent years. Still, their applicability to actual PV power generation is controversial due to the number of electrical switches, physical locations, interconnections and complexity. This study proposes an adaptive two-step staircase (A2SS) static reconfiguration method. The technique is experimentally validated in several conditions and compared with the conventional TCT connection, single-step staircase (1SS) static reconfiguration method, Arrow soduku, modified odd–even–prime (MOEP) and two-step staircase(2SS) static reconfiguration method. For the eight shading cases of LN, LW, LD, Ran, Cen, Cor, CD, and Plus at SET#1, after reconfiguring the PV array using A2SS, the power has a significant improvement of 17.6%, 17.0%, 13.4%, 13.4%, 20.6%, 20.2%, 3.1%, and 0.82% than TCT. In the four shading cases of Lr. C, Lr. O, Lr. T, and Lr. U at SET#2, the power showed a significant improvement of 11.8%, 9.2%, 10.7%, and 15.8% compared to TCT. It also has the best performance in various reconfiguration techniques, which are mentioned. In addition, the A2SS reconfiguration method can be better applied to various sizes of PV arrays. By optimizing the shading distribution and adjusting the row irradiance deviation, the power stability of PV power generation is improved while maximizing energy efficiency.

Simulation-Guided Analysis towards Trench Depth Optimization for Enhanced Flexibility in Stretch-Free, Shape-Induced Interconnects for Flexible Electronics.

In this paper, we present an optimization of the planar manufacturing scheme for stretch-free, shape-induced metal interconnects to simplify fabrication with the aim of maximizing the flexibility in a structure regarding stress and strain. The formation of trenches between silicon islands is actively used in the lithographic process to create arc shape structures by spin coating resists into the trenches. The resulting resist form is used as a template for the metal lines, which are structured on top. Because this arc shape is beneficial for the flexibility of these bridges. The trench depth as a key parameter for the stress distribution is investigated by applying numerical simulations. The simulated results show that the increase in penetration depth of the metal bridge into the trench increases the tensile load which is converted into a shear force Q(x), that usually leads to increased strains the structure can generate. For the fabrication, the filling of the trenches with resists is optimized by varying the spin speed. Compared to theoretical resistance, the current-voltage measurements of the metal bridges show a similar behavior and almost every structural variation is capable of functioning as a flexible electrical interconnect in a complete island-bridge array.

Microfluidic Lab-on-CMOS Packaging Using Wafer-Level Molding and 3D-Printed Interconnects.

Lab-on-a-chip (LoC) technologies continue to promise lower cost and more accessible platforms for performing biomedical testing in low-cost and disposable form factors. Lab-on-CMOS or lab-on-microchip methods extend this paradigm by merging passive LoC systems with active complementary metal-oxide semiconductor (CMOS) integrated circuits (IC) to enable front-end signal conditioning and digitization immediately next to sensors in fluid channels. However, integrating ICs with microfluidics remains a challenge due to size mismatch and geometric constraints, such as non-planar wirebonds or flip-chip approaches in conflict with planar microfluidics. In this work, we present a hybrid packaging solution for IC-enabled microfluidic sensor systems. Our approach uses a combination of wafer-level molding and direct-write 3D printed interconnects, which are compatible with post-fabrication of planar dielectric and microfluidic layers. In addition, high-resolution direct-write printing can be used to rapidly fabricate electrical interconnects at a scale compatible with IC packaging without the need for fixed tooling. Two demonstration sensor-in-package systems with integrated microfluidics are shown, including measurement of electrical impedance and optical scattering to detect and size particles flowing through microfluidic channels over or adjacent to CMOS sensor and read-out ICs. The approach enables fabrication of impedance measurement electrodes less than 1 mm from the readout IC, directly on package surface. As shown, direct fluid contact with the IC surface is prevented by passivation, but long-term this approach can also enable fluid access to IC-integrated electrodes or other top-level IC features, making it broadly enabling for lab-on-CMOS applications.

A method for batch modification of neural microelectrodes via removable electrical interconnection

The modification on the surface of neural electrodes is critical for improving the signal-to-noise ratio (SNR) and prolonging the recording time. Electrodeposition is a simple and practical modification technique that has been applied to a wide range of materials. However, the traditional electrodeposition becomes increasingly inefficient as the electrode channels dramatically increase since it is performed one by one. Short-circuiting multiple electrode sites and then modifying them together can significantly improve efficiency. But it remains a significant challenge to reliably connect hundreds or thousands of electrodes before the electrodeposition and to safely and easily disconnect them afterward. An approach of removable electrical connection was adopted to solve this problem. A kind of silver nanowire (AgNW) conductive ink with water as the dispersion was chosen to connect all the electrodes for simultaneous electrodeposition temporarily electrically. This approach makes the electrodeposition process convenient and reliable. Above all, the proposed approach is compatible with a wide range of Multi-electrode arrays (MEAs) fabricated from different materials.

A Review of Mechanism and Technology of Hybrid Bonding

Abstract With the development of semiconductor technology, traditional flip-chip bonding has been difficult to meet the high-density, high-reliability requirements of advanced packaging technology. As an advanced three-dimensional stacked packaging technology, Cu-SiO2 hybrid bonding technology can achieve high-density electrical interconnection without bumps, which expands the transmission performance and interconnection density of chips greatly. However, the investigation on Cu-SiO2 bonding is far from mature, and many researchers are studying Cu-SiO2 bonding passionately. There are many technologies that use different bonding mechanisms to achieve Cu-SiO2 bonding, which will affect the bonding strength directly. We review the mechanism and research progress of Cu-Cu bonding, SiO2-SiO2 bonding. What is more, we summarize the comparison of bonding conditions and bonding strength of various methods furtherly. According to the bonding mechanism, we propose some economical solutions for low-temperature Cu-SiO2 hybrid bonding, with the aim of providing certain references for the further development of advanced semiconductor packaging.

Bone Fracture Healing under the Intervention of a Stretchable Ultrasound Array.

Ultrasound treatment has been recognized as an effective and noninvasive approach to promote fracture healing. However, traditional rigid ultrasound probe is bulky, requiring cumbersome manual operations and inducing unfavorable side effects when functioning, which precludes the wide application of ultrasound in bone fracture healing. Here, we report a stretchable ultrasound array for bone fracture healing, which features high-performance 1-3 piezoelectric composites as transducers, stretchable multilayered serpentine metal films in a bridge-island pattern as electrical interconnects, soft elastomeric membranes as encapsulations, and polydimethylsiloxane (PDMS) with low curing agent ratio as adhesive layers. The resulting ultrasound array offers the benefits of large stretchability for easy skin integration and effective affecting region for simple skin alignment with good electromechanical performance. Experimental investigations of the stretchable ultrasound array on the delayed union model in femoral shafts of rats show that the callus growth is more active in the second week of treatment and the fracture site is completely osseous healed in the sixth week of treatment. Various bone quality indicators (e.g., bone modulus, bone mineral density, bone tissue/total tissue volume, and trabecular bone thickness) could be enhanced with the intervention of a stretchable ultrasound array. Histological and immunohistochemical examinations indicate that ultrasound promotes osteoblast differentiation, bone formation, and remodeling by promoting the expression of osteopontin (OPN) and runt-related transcription factor 2 (RUNX2). This work provides an effective tool for bone fracture healing in a simple and convenient manner and creates engineering opportunities for applying ultrasound in medical applications.

Power Through Pressure: How Interconnection Became Part of the EU's Overarching Climate and Energy Policy

AbstractInterconnection is important to attain several important EU climate and energy targets. Drawing on data from 56 stakeholder interviews, stakeholder event participation and document studies, this study enquires as to why electricity interconnection became a part of the EU's overarching climate and energy policy in 2014. The theoretical approaches liberal intergovernmentalism (LI) and the advocacy coalition framework (ACF) are tested complementarily. LI received support: member states, particularly Portugal and Spain, were essential for the outcome. These successfully played the veto card in the high‐level negotiations for the 2030 Climate and Energy Policy Framework, leading to the first inclusion of concrete interconnection targets in it and interconnection becoming a European Commission priority. ACF received partial support: a ‘green’ long‐term, multi‐level advocacy coalition consisting of the renewables industry, environmental organisations and others promoted a binding target for electricity interconnection. This ‘green’ advocacy coalition was instrumental in aiding Portugal and Spain.