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Lossy dielectrics in printed circuit boards and integrated circuit packages can be represented by using a Debye model. This allows accurate signal and power integrity analysis, which depends on the accuracy of material properties of the board or package. Such a Debye model needs multiple poles for accurate representation of the loss tangent over a broad frequency range. Electromagnetic and circuit simulations can then include the impact of frequency-dependent dielectric constant and loss. In this letter, we present an efficient and closed-form multipole Debye model, automating the modeling of lossy dielectrics for inclusion in time-domain electromagnetic or circuit simulators.

High-speed transmission lines are commonly routed as differential lines to control sensitivity to noise on the reference planes at higher speeds. Differential lines are typically characterized in terms of mixed-mode scattering parameters, as they provide insight into the behavior of differential and common signals, as well as the mode conversion among them. These mixed-mode scattering parameters can be mathematically obtained from single-ended parameters, which can, for example, be measured with a four-port vector network analyzer. There has been recent efforts to develop extended or modified versions of mixed-mode scattering parameters, especially for tightly-coupled lines. This can be a point of confusion in interpreting the behavior of differential lines. In this paper, we introduce the mixed-port scattering and hybrid parameters, which do not suffer from any such ambiguous definitions. Mixed-port hybrid parameters are the most natural way to represent any four-port differential circuit, as they are based on intuitive differential and common-port excitations of the network. They also enable extraction of the current division factor experimentally, which is a critical parameter for electromagnetic interference analysis of differential lines. Mixed-port scattering parameters are also defined based on common and differential port excitations, allowing a simpler interpretation than their mixed-mode counterparts, without the need for defining even, odd, common, or differential-mode impedances. As such, mixed-port scattering and hybrid parameters can be used to analyze the performance of a general differential network, certainly including coupled or asymmetrical lines, without any ambiguity.

The quality of molded packages heavily depends on the process parameters of the molding process and on the material characteristics of epoxy molding compounds (EMCs). When defects are introduced into the electronic packages in one of the last steps in the manufacturing process, namely, during encapsulation, it may cause high failure costs. To decrease the number of defects due to the molding process, a comprehensive understanding of the impact of process parameters and variations in the characteristics of the EMC on package quality is necessary. This study aimed at supporting a deeper understanding of the influence of process parameters and variations in the material characteristics of the EMC on package quality. A systematic approach was introduced to generate a process model describing the correlation between process parameters and package quality to obtain optimum process parameters for the transfer molding process. The influence of the alterations in material characteristics of the EMC due to prolonged storage duration and humidity on void formation and wire sweep was investigated. An online monitoring method, dielectric analysis (DEA), was implemented into the transfer molding process to monitor the variations in the cure behavior of the EMC. A second molding compound was used to analyze the similarities in the alteration behavior of the molding compounds when subjected to the same preconditioning and to generalize the characteristic information obtained from DEA.

Providing low IR-drop and inductance are two major roles of power and ground (PG) planes in chip packages and boards. However, planes can also cause switching noise coupling, especially when they resonate. This is a concern for mixed-signal boards, high-speed I/Os, and electromagnetic compatibility. Discrete decoupling capacitors are ineffective to control switching noise at gigahertz frequency regime due to their inductance. To filter such high-frequency noise, a possible approach is modifying the shape of the PG planes, such as in power islands or electromagnetic bandgap structures. In this paper, we introduce the nonoverlapping PG planes design methodology for filtering of gigahertz power plane noise. Unlike existing approaches, our approach is simple and has wide bandwidth, while avoiding narrow inductive bridges that increase IR-drop.

The virtual ground fence (VGF) has been recently proposed to filter power plane noise in gigahertz frequency range. The VGF has distinct advantages over existing approaches, such as power islands and electromagnetic bandgap structures: The IR drop is not increased; transmission-line return-path discontinuities can be avoided; and the design procedure is simple. The basic VGF is created by using quarter-wave resonators referenced to the power or the ground plane. At the design frequency, the resonator creates an ac short circuit between the power and ground planes. An array of such resonators can be placed in electrically short intervals to create a VGF. Power plane noise will then ideally be shorted to ground at the location of the VGF. The operation principle is similar to the series resonance of a decoupling capacitor, which is usually ineffective in the gigahertz frequency range. This paper proposes a new design procedure for determining the number of quarter-wave resonators needed, their characteristic impedances, and their placement on the board. The design approach is based on the well-known insertion loss method in microwave filter theory, which allows for higher order VGF designs consisting of multiple rows of resonators.

Das deutsche DVS-Merkblatt 2811 zur qualitativen und auch quantitativen Überprüfung von Draht- Bondverbindungen in Labor und Praxis (Fertigung) - ,Prüfverfahren für Drahtbondverbindungen' - entstand vor über 20 Jahren als Folge intensiver Diskussionen im Industriearbeitskreis AG A2.4 ,Bonden' des DVS [1]. Dieses DVS-Merkblatt 2811 hob sich bereits bei seiner Veröffentlichung im Jahr 1996 deutlich von internationalen Standards (MIL-Std-883, ASTM International [2, 3] durch schärfe Beurteilungskriterien (z. B. minimal zulässige Pullkräfte) ab, kam dadurch auch über die Landesgrenzen hinweg zur industriellen Anwendung und wurde gar eine Art Vorlage für industriespezifische Qualifikationsmaßnahmen. Nun haben sich aber über die Jahre hinweg nicht nur die zu verarbeitenden Drahtmaterialien (neu: Au-Legierungen, Cu, Ag) verändert, sondern auch die vollautomatisch bondbaren Drahtdurchmesser wurden immer kleiner (< 17,5 mm). Ferner war der Test von Dickdraht- oder Bändchen-Bondverbindungen bisher nicht Bestandteil.

The evolution of microstructural gradients, especially crystallographic texture gradients, after ultrasonic wire bonding process and after active power cycling (APC) of high purity, heavy aluminum (Al) wires is studied by electron backscatter diffraction (EBSD) and nanoindentation. The results improve the knowledge about microstructural changes and arrangements after wire bonding and during APC. After ultrasonic deformation by wire bonding, the evolution of a distinct rotated cube (RC) textured area within the wedge was proved by EBSD analysis. The RC texture is discussed as a result of shear deformation and oriented grain growth. Decreased hardness within the RC textured area provides evidence for local softening effects during wire bonding. During APC, besides crack propagation, grain coarsening as well as local low angle boundary migration occurs and the wedge texture changes to an overall random orientation. Effects of microstructure on the crack growth behavior were discussed and suggestions for the improvement of wire bond reliability were derived.

For radar applications, the W-band frequency range (75 - 110 GHz) is a good candidate for high-resolution distance measurement and remote detection of small or hidden objects in distances of 10 cm to >> 20 m. As electromagnetic waves in this frequency range can easily penetrate rough atmosphere like fog, smoke or dust, W-band radars are perfectly suited for automotive, aviation, industrial and security applications. Additional benefit is that atmosphere has an absorption minimum at 94 GHz, so relative small output power is sufficient to achieve long range coverage. By combining and enhancing knowledge from the disciplines of heterogeneous integration technology and compound semiconductor-technology, the Fraunhofer Institutes IAF, IPA and IZM developed a miniaturized and low cost 94 GHz radar module. Result of this approach is a highly miniaturized radar module built using a modular approach. The radar components are mounted on a dedicated RF-NF-hybrid PCB while the signal processing is done on a separate board stacked below. This hybrid RF-module is combined with highly integrated digital processing PCB via micro connectors in a way that the radar system and an adapted conical HDPE-lens fit into an aluminum housing of 42x80x27 mm³ with a weight of only 160 grams for the whole module. The paper will describe the technological basis for such a frequency modulated continuous wave [FMCW] W-band radar module and describe in detail the technological features that enabled the assembly of such a miniaturized but high-performance system. The module yields an evaluated distance measurement accuracy of 5 ppm (5 mm deviation per meter target distance) while its low weight and small dimensions pave the way for a variety of new applications, including mobile operation.