This paper presents an accurate and efficient on-wafer calibration algorithm of broadband scattering-parameter measurements for radio-frequency integrated circuit production test applications. Three on-chip calibration standards with the same probe positions as those of the devices under test (DUTs) were designed to take advantage of fixed probe heads in the x-y directions during calibration and measurements. In addition, three on-chip standards-a series resistor and a shunt resistor (both of which have an offset line segment) as well as a transmission line (TL)-do not have to be characterized in advance, and the measurement reference impedance can be acquired further though self-calibration without an impedance-standard substrate (ISS). Simulation studies and experimental confirmation were conducted on GaAs substrates, from 2 to 110 GHz, in addition to comparisons of the multiline thru-reflect-line (TRL) calibration results.

This Special Section is a collection of six articles highlighting the main directions that the researchers from academia and industry are exploring for managing signal and power integrity (SPI) through advanced modeling techniques. A previous Special Section (Part 1) on Addressing Signal and Power Integrity in Future Generation Systems presented eight papers in the two main categories of technological and design aspects. As in Part 1, the authors were selected by looking at the best papers presented at two major IEEE conferences dedicated to SPI topics that were held annually in the United States (EPEPS2015, San Jose, CA, USA) and Europe (SPI2016, Turin, Italy). Together, these two Special Sections give a good overview of leading research in advancing SPI in systems.

One of the most appealing properties of carbon nanotube (CNT) interconnects is the possibility of exhibiting, under certain circumstances, a negative temperature coefficient of the electrical resistance, i.e., a resistance that decreases as temperature increases. In the past, this behavior has been theoretically predicted and experimentally observed, but only for a certain class of CNTs, with short lengths (up to some micrometers) and in a limited range of temperature. This paper demonstrates the possibility of obtaining such a desirable behavior in a larger scale (up to fractions of millimeters). An accurate electrothermal model is used to define the conditions under which a negative derivative of the resistance may be observed. Then, a novel bottom-up technique is proposed to realize the interconnect, by self-assembly of short CNTs. The experimental results of an electrothermal characterization demonstrate the possibility of obtaining a negative temperature coefficient of the resistance and confirm the validity of the theoretical model.

Ensuring signal and power integrity (SPI) is a primary concern for the electronic packaging community. The continuous increase of operating frequencies, combined with more and more aggressive miniaturization and integration strategies, poses tremendous challenges to designers. Every transistor must receive power with reduced noise, and all signals must be received properly, despite the plethora of signal and power degradation effects due to crosstalk and electromagnetic interaction, losses, and dispersion due to material nonidealities, reflections due to mismatches, and discontinuities, just to name a few. Proper handling of such effects requires precise characterization through modeling, suitable design strategies to minimize them, and the technological ability to realize the design.

IEEE transactions on components, packaging, and manufacturing technology
ISSN：2156-3950 volume：7 Issue：6 page：855-861
Hamilton, Michael C
;
Yu, Fang
;
Johnson, R. Wayne

Ag sintering is a promising die-attach technique to fabricate digital and analog thick-film modules for 300 °C applications. In this paper, a low-temperature, pressure-assisted rapid sintering process was developed. Process optimization decreased the sintering time to 1 min, which allowed the use of an FC150 thermocompression flip-chip/die bonder for automated die attach instead of a hydraulic press, improving the manufacturability. The porosity of the sintered Ag layer was decreased from 30% (pressureless assembly) to 15% with the application of a low pressure (7.6 MPa) during the 1-min sintering process for large die. The average shear strength for the 3 <inline-formula> <tex-math notation="LaTeX">\times </tex-math></inline-formula> 3-mm 2 die was 70.7 MPa, and the 8 <inline-formula> <tex-math notation="LaTeX">\times8 </tex-math></inline-formula>-mm 2 die could not be sheared off due to the 100-kg force limit of the shear test module. Both Ag and Au metallization (die and substrate) were studied. A new substrate metallization combination was found that was compatible with thick-film Au metallized substrates.

For the first time, this paper presents a novel approach for designing a coupler with arbitrary division, optional phase difference, and alternative input/output impedances. In the section of theoretical analysis, rigorous closed-form design equations are derived, and explicit methodology for computer-aided design is given based on the equations. To validate the idea, several numerical examples extracted from the design procedure are constructed and demonstrated. Eventually, three prototypes of the coupler are fabricated, and experiments are carried out. The excellent agreement between the theoretical and experimental results sufficiently verifies the theoretical methodology. This proposed coupler is well applicable to the applications that require high flexibility in couplers' performances.

IEEE transactions on components, packaging, and manufacturing technology
ISSN：2156-3950 volume：7 Issue：4 page：621-629
Kishk, Ahmed A
;
Shams, Shoukry I

It is useful to determine the stopband of a bed of nails that can be used for packaging applications. The traditional methodology to identify the cell characteristics is to use the eigenmode solver, which is a numerical method that cannot be validated using a measurement setup. Here, we introduce a mathematical procedure to extract the dispersion relation out of the scattering parameters. The scattering parameters express the transmission and the reflection at the ports, which are functions of the phase constant of the propagating modes inside the device under test. A measurement setup is established by placing several successive cell rows inside a <inline-formula> <tex-math notation="LaTeX">Ku </tex-math></inline-formula>-band rectangular waveguide. The proposed algorithm is validated through examples of well-known dispersion relations. The extracted dispersion relation with the introduced methodology is in good agreement with the one obtained from the eigenmode solver. The ride gap waveguide is used as an application example.

Based on the recognition that near-end crosstalk propagating to the far end is the primary source of crosstalk noise in short unterminated channels, an approach to improve the signal integrity on such channels significantly is described and demonstrated. The basic physics of crosstalk reduction by matrix matching is described and illustrated numerically. Then, large potential gains for three on-package interconnect application examples are shown. A nominal strip-line configuration based on standard package design rules and including realistic modeling assumptions yields 50.4% reduced channel power at equal performance. The same design can be converted into microstrip without degrading the eye height and channel power. For a dense multichip package with design of experiment simulation, the worst-case eye width is improved by 114%.

The light-emitting diode (LED), a semiconductor optoelectronic device, is increasingly introduced into automotive signaling and lighting applications principally due to its exciting design style and long lifetime. Focusing on automotive contexts, numerous researchers have conducted the thermal optimization concerning structure and material properties in LED automotive lamps to maintain the junction temperature operating within a favorable range. However, these efforts mostly rely on thermal simulations with partly component models and specific boundary conditions, and moreover little temperature tolerance has been given from a whole-lamp-level aspect consisting of the electrical, optical, and mechanical requirements. To qualify the temperature tolerance in the thermal design for LED automotive lamps in in-vehicle environment, in this paper, after a description of the design database, the thermal cost objective function, weighted by the electrical, optical, and mechanical objectives, is defined. Then, the multiphysical 3-D simulation model has been made with whole parts in the LED automotive lamp, calibrated by junction temperatures of the typical modules, and integrated with the built database for a graphic user interface application. Finally the temperature sensitivity analysis based on the integrated platform has been performed to accurately estimate the temperature tolerance of the LED automotive lamp. The suggested methodology and experimental results cast light on balancing between the failure risks and costs in LED automotive lamps in the future cars.

A <inline-formula> <tex-math notation="LaTeX">2 \times 2 </tex-math></inline-formula> dual-polarized antenna subarray with filtering responses is proposed in this paper. This antenna subarray is a multilayered 3-D geometry, including a dual-path <inline-formula> <tex-math notation="LaTeX">1 \times 4 </tex-math></inline-formula> feeding network and four cavity-backed slot antennas. The isolation performance between two input ports is greatly improved by a novel method, which only needs to modify several vias in a square resonator. Cavities in the feeding network are properly arranged and coupled using different coupling structures, so that the operation modes in each cavity for different paths can always remain orthogonal, which enables the subarray to exhibit not only filtering functions (in both reflection coefficients and gain responses), but also a low cross-polarization level. A prototype is fabricated with a center frequency of 37 GHz and a bandwidth of 600 MHz for demonstration. Good agreement is achieved between simulation and measurement, for both <inline-formula> <tex-math notation="LaTeX">S </tex-math></inline-formula>-parameter and far-field results. The proposed filtering dual-polarized antenna array is very suitable to be employed as the subarray in millimeter-wave 5G base stations to reduce the complexity and integration loss of such beamforming systems.