High temperature Silicon Carbide (SiC) integrated circuit (IC) processes have enabled devices that operate at >450°C for more than a year. These results have established the need for more advanced and practical packaging strategies. Off the shelf state of the art packages cannot withstand the same high temperatures as the semiconductor can for long periods of time. Packaging SiC die to survive temperatures >450°C, while also maintaining a reasonable packaging strategy that is agile, rapid, and modular, presents new challenges. Presented is a technique for packaging SiC die with a focus on additive manufacturing, modular design scaling, and rugged survivability. This packaging strategy utilizes state of the art Additive Manufacturing (AM) methods, using an nScrypt 3Dn-Tabletop printer, together with stereolithography (SLA) digital light processing (DLP) 3D printing. Ultra-violet (UV) curable ceramic resins are used to create high temperature connectors. A design environment is also described, in which first time correct, interconnect layers are verified in software to reduce the risk of errors. A Ceramic Wiring Board Process Design Kit (CWBPDK) allows the design of single or multiple layers of metal, with fabricated SiC die. This interconnect is verified with standard design rule checking (DRC) and layout vs. schematic (LVS) software. Entire systems in packages can be verified using multiple SiC die. Input and output pins (I/O) are connected to these modules using metal connectors. After design, manufacturing can be performed in just a few days. A system in package for driving a stepper motor was designed and fabricated using this packaging method. The motor actuator design utilizes four separate SiC die. These die contain large JFETs designed for sourcing current in a unipolar stepper motor architecture. This module was placed in a furnace at 470°C and demonstrated functional operation for over 1000 hours. These devices were able to source an average of 30 mA in >400°C temperatures to drive the room temperature stepper motor. A high I/O count, next generation package for discrete SiC chips was also designed using this packaging system. A single large JFET component was soaked for over 100 hours at both 500°C and 800°C. Utilizing Ozark IC’s automated test design environment, several DC and transient variables were captured for both tests and will be presented.

This paper introduces a multilayer, wideband, high-efficiency, patch antenna with embedded cavity and monolithic microwave integrated circuit (MMIC) phase shifter using direct digital manufacturing (DDM). DDM platform combines fused deposition modeling (FDM) of thermoplastics and micro-dispensing of silver nanoparticle inks to realize cost-effective customized multilayer RF structures. DDM offers design flexibilities in terms of material properties, thicknesses, and shapes that can be harnessed to realize high-performance antennas and arrays. Specifically, an X-band phased array antenna element with embedded cavity and MMIC phase shifter is demonstrated with 81% radiation efficiency (excluding IC loss) and 23% impedance matching bandwidth.

Design and performance of a fully-printed Ku-band aperture coupled patch antenna manufactured by making use of a direct digital manufacturing (DDM) approach that integrates fused deposition of acrylonitrile butadiene styrene (ABS) thermoplastics with in-situ micro-dispensing of conductive silver paste (CB028) is reported. Microstrip line characterizations demonstrate that the microstrip line feed loss of the antenna is minimized by printing ABS in parallel with the line directions. A wideband (20%) performance is achieved by employing a multilayer printing approach. Compared to existing work in literature, the presented antenna stands out as being fully-printed, operating within the Ku-band, and exhibiting high radiation efficiency (6.5 dB gain) with wide bandwidth performance.

Direct digital manufacturing (DDM) is an emerging technology that is finding its place across a wide array of industries and applications as a cost-effective solution for low volume and mass customizable production. This technology encompasses a class of digital manufacturing techniques which can be combined to enable multimaterial fabrication and postprocessing. One of the promising applications for DDM is structural electronics, where lightweight printed plastics provide mechanical support as a fixture, package, or structural member and also host the electrical interconnects and devices, all in a contiguous fashion. Microwave structural electronics is a specific class of such systems for which the printing resolution as well as electrical and surface properties of the materials are especially important. This paper presents the current state of DDM technology, fundamental research into the electrical and mechanical properties of as-printed structures, and novel 3-D printed structures operating from C-band through Ku-band.

Additive Manufacturing (AM) continues to gain popularity for its ability to produce complexlyâ€"shaped final use components that are impractical to manufacture by traditional methods; however, additive manufactured parts contain complex mesostructures that result in directionallyâ€"dependent mechanical properties that have yet to be fully characterized. This effort demonstrates a framework of experimental and analytical methods needed to characterize the uniaxial monotonic behavior of fused deposition modeling PLA using tensile and compressive experiments on specimens printed at various orientations. Based on experimental results, the asymmetry and anisotropy of tensile and compressive response were analyzed for a candidate material. Specimens from different orientations underwent microscopy and failure surface analysis to correlate test data. The material was observed to exhibit tetragonal behavior with tensileâ€"compressive asymmetry. To help validate the model, a componentâ€"level study was performed. A newlyâ€"developed square donut (i.e., prismatic torus) was printed in multiple orientations, tested, and compared to simulations. The experimental and simulated results show a strong correlation. Based on the collection of results, analysis, and computations, this work demonstrates a practice that can be used to characterize similar materials for use in components.

This paper reports on the design, fabrication and characterization of a 3-D printed RF front end for a 2.45 GHz phased array unit cell. The printed unit cell, which includes a circularly-polarized dipole antenna, a miniaturized capacitive-loaded open-loop resonator filter and a 4-bit phase shifter, is fabricated using a direct digital manufacturing (DDM) approach that integrates fused deposition of thermoplastic substrates with micro-dispensing for deposition of conductive traces. The individual components are combined in a passive phased array antenna unit cell comprised of seven stacked substrate layers with seven conductor layers. The measured return loss of the unit cell is > 12 dB across the 2.45 GHz ISM band and the measured gain is -11 dBi including all components. Experimental and simulation-based characterization is performed to investigate electrical properties of as-printed materials, in particular the inhomogeneity of printed thick-film conductors and substrate surface roughness. The results demonstrate the strong potential for fully-printed RF front ends for light weight, low cost, conformal and readily customized applications.

Using micro-dispensing with exceptional volume control it is possible to print in 3D space a wide variety of materials and including solders, epoxies, conductive adhesives and ceramic filled polymers. These can be used to build 3D structures and utilizing a 3D Printing approach which is also known as Computer Aided Design and Computer Aided Manufacturing (CAD/CAM). The advanced technology enables 3D printing of electronics but it also enables smaller solder and adhesive dots; 75 microns and less. It is possible to place these on any package in 3D space. Demonstrations for this technology have shown that it is possible to print less than 50 micron wide lines and dots. Additionally a wide range of materials that will be required in future packaging can be dispensed. These smaller features provide sub nanoliter volume. This is possible given the less than 100 picoliter volume control during dispensing and including highly viscous materials. Demonstrations of smaller printed dots and lines for electronic circuits and packaging will be shown. In addition, 3D circuitry that is 3D printed and contains no solder will also be shown, demonstrating the future of printed circuits. Introduction Electronic packaging has been a stable research topic since the vacuum tube era. These were physically large and fragile devices and typically the electronic connection was a mechanical socket that ensured good contact over a large surface area. The issues involved were both electrical contact and mechanical security or ruggedness. The evolution of electronics from vacuum tubes to semiconductors presented opportunities to shrink the electronic devices without reducing the performance. This dramatic change forced a change in connections as well and the idea of mechanically connecting electronics needed to be studied. Solder was a very old, literally thousands of years old [1], technology, but for electronics was a natural fit. A natural fit given two reasons, one was the obvious electrical attributes, but the second was the mechanical flex that solder could provide between two joining surfaces [2]. This became especially important with two dissimilar surfaces. Solder also became its own research topic and the growth and maturity of this process has proven to be one of the most important contributions to electronic packaging since the semiconductor; almost all electronic devices today have solder. The mechanical bond was important, but this alone was not enough given the rugged requirements of some of the electronic devices. The extra ruggedness would be provided using mechanical devices and if the electronics were too small, then another technology that was also thousands of years old was used, glue [3]. Adhesives primary contribution was to enhance ruggedness but adding features such as conductivity to adhesives provided additional value. Solders and adhesives are an important part of electronic packaging and the future of electronics is to increase functions per volume which implies tighter pitch and smaller traces, smaller pads, smaller solder dots and finer features in adhesive patterns. This requires improved methods for applying solder and adhesives. This paper will cover in part, advanced dispensing of fine resolution solder and adhesive dots and lines. Additionally, just as electronic packaging has evolved from mechanical connections to solder, a future of monolithic electronic packaging will evolve. The idea of circuits in structures has been presented previously by Church et el [4]. Additional demonstrations of printed circuit structures will be shown and the concept of using similar technology to dispensing dots and lines of solder and adhesive will be explained. The concept of dispensing a wide range of materials in three dimensions presents a potential change in electronic packaging. This paper will cover the concept of combining dispensing technologies on a single platform to build integrated and monolithic electronic structural circuits.

Embedded Passive Technology is a viable technology that has been reliably used in the defense and aerospace industry for over 20 years. Embedded Passive (Resistors and Capacitors) Technology have a great potential for high frequency and high density applications. It also provides better signal performance, reduced parasitic and cross talk. This paper summarizes the selection of resistor embedded materials, evaluations of resistive material (Phase 1) and duplication of a complex digital design (Phase 2). Phase 1 – Ticer’s TCR® resistive materials (Foil 25Ω/sq NiCr and 1kΩ/sq CrSiO) and Ohmega resistive-Ply materials (Ohmega-Ply 25Ω/sq and 250Ω/sq NiP) were chosen for evaluation. Phase 2 – Due to the high level of complexity and advance materials dielectric, the Digital Imaging Processor unit was chosen as an evaluation vehicle. Process Evaluation for embedded was used to determine present process gaps for laser trimming, fabrication material, raw board test and defining specifications for DFM and layout design.