Conference Agenda

Ceramic materials have long been employed in electronic packaging, particularly in devices designed for harsh environmental conditions such as cryogenic settings. With the escalating technological demands for high-density integration of devices utilized in harsh environments like space, cryogenics, high-temperature, or high-voltage applications—including quantum optoelectronic devices or sensor systems deployed on nanosatellites—novel fabrication solutions are imperative. These solutions must not only prioritize performance and ultra-high fabrication resolutions tailored to demanding applications but also consider factors such as fabrication cost, time, and environmental impact.

Addressing these challenges necessitates the realization of intricate micrometric 3D ceramic structures incorporating sophisticated and densely packed metallic circuits to facilitate high-density integration of microdevices. In this regard, 3D ceramic micrometric interconnect devices emerge as highly promising solutions, minimizing the need for traditional techniques like wire bonding and resins, which often pose technical limitations in harsh environments.

Among the various techniques applied for their realization, the combined additive-subtractive approach of pulse laser microprocessing currently stands out as the singular method encompassing all the prerequisites for their fabrication. Notably, its ultra-high precision within a few microns, both in geometrical configuration and material machining selectivity, enables the creation of intricate interconnect circuits and on-chip component integration within sophisticated 3D designs.

The precise control of laser pulse energy, both temporally and spatially, has enabled selective processing of circuit structures, allowing characterization of their structure, material, surface, and mechanical properties based on laser beam and sequence properties. This integrated approach offers a pathway towards the development of advanced ceramic interconnect devices tailored to meet the stringent requirements of modern electronic applications in extreme environments.

Laser direct structuring (LDS) technology has been developed for application on molded interconnection devices (MIDs). This work aims to provide evidence that a smaller-scale application of LDS technology is feasible for IC packages based on leadframes. Through direct copper interconnection (DCI) technology, it has been demonstrated the possibility to create more flexible, high-performance interconnections that are also able to reduce the size of the package. A UV 355nm wavelength laser has been used to perform laser structuring on the mold, realizing the three main structures necessary for the creation of the interconnection path: the vias on die, the vias on leads, and the traces that connect the two types of vias. In these structures, copper is grown through two plating processes, electroless and electroplating, to achieve the interconnection. To realize die and lead vias, laser parameters have been varied in order to obtain vias with different diameters. A characterization have been performed on vias realized by laser with diameters in the range of 65-100μm for die vias, with a depth of 100μm, and diameters in the range of 225-375μm with a depth of 375μm for lead vias. To investigate the platability, structures with an aspect ratio (bottom vias diameter/depth) less than 1 have also been realized. Vias have been plated with three different plating recipes, each with a different copper thickness target. A visual inspection have been carried out using an optical microscope and SEM to evaluate the quality, geometries and to measure diameters of the structures realized by laser. To prove the correlation between plating process and laser structured vias, with different diameters, cross sections have been performed.

Worldwide microelectronics industry trends indicate increasing miniaturization of electronic devices for their seamless integration into daily life of consumers via wireless technologies, e.g., wearable health monitoring devices, flexible foldable devices, or miniature hearing aids. The miniaturization poses severe design and packaging challenges for the electronic components as the small scale physical phenomena become more significant. The heat generated by the chips and sensors must be dissipated in an efficient manner through optimally designed heat sinks to avoid heavy thermal stress cycles on the components. At the same time, the heat sinks should not interfere with the antenna signals, which requires their appropriate placements on the board. Some devices may require shielding from electric and magnetic fields. Additionally, miniaturized accelerometers suffer from nonlinear squeeze film damping effects, which adds even more complexity to the design requirements. To address these challenges, multiphysics simulations form an integral part of the design process and provide essential insights through multiple iterations to arrive at an optimal design to be manufactured. In this white paper, we present a cloud-based multiphysics simulation tool called Quanscient Allsolve. The tool is based on the finite element method and seamlessly integrates multiple physical processes, such as heat and fluid flow, structural mechanics, electromagnetic waves, electrostatics, magnetism, and many others. These physics can be modeled independently or in a strongly coupled way to perform various types of numerical simulations, such as eigenmode analysis, static and transient analysis, harmonic and multiharmonic analysis. The proprietary algorithms specifically optimized for cloud scaling enable running large-scale simulations as well as multiple of such simulations at the same time to accelerate the design iteration process. Faster design iterations reduce the development times and the time-to-market bringing the product to consumers at the earliest.

Topics: Multiphysics simulation, Numerical modeling, Finite Element Method

Keywords: thermal, mechanical, electromagnetic waves, antennas, magnetism, electrostatics, finite element method, allsolve

Liquid metals of gallium-based alloys have a low melting point and remain in liquid form at room temperature and below. The use of this attribute together with the characteristics of metals has brought revolutionary use in the fields of microfluidics and microelectronics. Abilities such as compliance, resistance to fatigue and allowing for shape morphing while maintaining high electrical and thermal conductivity have opened new opportunities in wearable and implantable electronics, robotics and haptics. The implementation of gallium-based liquid metals as interconnections for pliable printed circuit boards, shape-changing and haptic sensors and devices have been extensively investigated.

The efficient patterning of liquid metals is still the subject of research and optimization. The challenging factor is the combination of low viscosity, very high surface tension, and, under atmospheric conditions, the formation of a thin passivating solid oxide layer (1-3 nm in thickness). This phenomenon is utilized by needle dispensing technology (also known as direct ink writing) for the patterning of planar and 3D objects. The dispensing needle is set in close proximity to the substrate and the surface oxide layer is continuously sheared and reformed, creating a stabilizing shell around the LMA structure during deposition. High demands are therefore placed on the precise proximity control, as well as the evenness and cleanliness of the substrate. The technology enables the patterning of features down to 2 µm in the smallest dimension. However, the technique reaches its limitations in high throughput manufacturing and preferably suits prototyping and smaller-batch production of high-end devices.

Growing interest in personalized remote patient monitoring requires wearable electronic devices with significantly lower production costs, and therefore a more suitable fabrication methodology is essential. Non-contact jet dispensing of solder pastes, conductive adhesives, structural underfills, and sealing materials are common in many fields, including electronics, medtech, automotive and aeronautical industries. The utilization of precision contact-free deposition technology of liquid metals would contribute to overcoming the limiting factors and demands of the aforementioned technique and facilitate the challenges of production requirements. Results concerning determining the feasibility of digital non-contact patterning of liquid metal will be presented. The emphasis is put on optimizing the configuration and jetting performance of liquid metal for the deposition of planar features and interconnects. The process utilizes conventional jet valve dispensing equipment.