Stefano Piersanti

Transient Analysis of TSV Equivalent Circuit Considering Nonlinear MOS Capacitance Effects

An equivalent circuit model for the transient analysis of through-silicon vias (TSV) taking into account nonlinear metal-oxide-semiconductor effects is proposed. The model takes into account the nonlinear behavior of the doped silicon substrate in presence of the electric potential difference due to the transient voltage between the TSVs. The impact of time-variant capacitance between the via and the substrate on crosstalk and signal propagation is analyzed.

Impact of Frequency-Dependent and Nonlinear Parameters on Transient Analysis of Through Silicon Vias Equivalent Circuit

This paper introduces an equivalent circuit model for through silicon vias including the nonlinear effect of metal-oxide-semiconductor capacitance. This nonlinear effect is combined to the frequency-dependent via resistance and inductance, as well as capacitance and conductance of the silicon substrate for a transient analysis. The impact of frequency-dependent RLCG parameters and the nonlinear depletion capacitance on signal propagation, crosstalk and eye diagram is studied using the proposed equivalent circuit model.

Equivalent Circuit Modeling of Dielectric Hysteresis Loops in Through Silicon Vias

This paper proposes a numerical solution of the nonlinear equations that describes the hysteretic behavior of the coupling capacitance among through silicon vias in three-dimensional integrated circuits. Behavioral ordinary differential equations are formulated and solved by an equivalent circuit described in SPICE syntax. These results are then compared with those obtained by measurements.

Through silicon via time domain crosstalk modeling considering hysteretic coupling capacitance

The paper deals with the time domain modeling of the hysteretic behavior of the coupling capacitance from a through silicon via (TSV). The model is developed in such a way that it can be implemented into standard circuit simulators. Results showing the effect of the hysteresis on the electrical performances of the signal channel containing the TSV are shown and discussed.

Near-Field Shielding Performances of EMI Noise Suppression Absorbers

This paper describes a systematic study on the near-field behavior of an electromagnetic interference (EMI) noise suppression absorber materials considering two different types of commercial absorbers and different types of excitation source: at first, elementary electric dipole and elementary magnetic loop, and then using real dimensions of a coaxial cable for designing a dipole and loop. Virtual versions of the material are created and simulated with the purpose of understanding the mechanisms of high values of power loss when the absorber is in the near field of the source The focus of this study is the evaluation of the electromagnetic power balance in near field for each absorbing material and considered source to understand their near-field shielding properties. Full-wave simulations and measurement are performed and compared to verify the performance of the EMI noise suppression absorber materials in the near field.

Electric Dipole Equations in Very-Near-Field Conditions for Electromagnetic Shielding Assessment—Part II: Wave Impedance, Reflection, and Transmission

This paper analyzes, in a quantitative way, the properties of the spatial distribution at the interface of the wave impedance as defined by Schelkunoff, in order to understand if and under which assumptions his transmission line theory for the evaluation of the shielding effectiveness can be used in the near-field region of a radiating electric dipole. The spatial distribution of the wave impedance and the reflection, and transmission coefficients are computed by the analytical formulation developed in Part I, and compared to those computed by an accurate 3-D full-wave model.

Electric Dipole Equations in Very Near Field Conditions for Electromagnetic Shielding Assessment. Part I: Radiation Equations

The problem of a correct modeling of the electromagnetic field distribution in the near field region is one of the most challenging and interesting due to its direct implication in the engineering evaluation of the shielding effectiveness of materials and structures in close proximity of radiating sources. This paper deals with a detailed analysis on the applicability of the Schelkunoff theory of transmission lines for shielding assessment in near field. The contribution is divided in two Parts. The present Part I analyzes the characteristics of two principal closed form set of equations for the quick evaluation of the near field from an electric dipole. It discusses their assumptions and compares the values of electric (E) and magnetic (H) fields, and their statistics, with those coming from accurate three-dimensional full waves simulations considered as reference. The computed E and H are the input for Part II where the wave impedance and the reflection, transmission, and shielding effectiveness coefficients are computed and discussed.

Through Silicon Via (TSV) Defect Modeling, Measurement, and Analysis

Through silicon via (TSV)-based 3-D integrated circuit has introduced the solution to limitlessly growing demand on high system bandwidth, low power consumption, and small form factor of electronic devices. As the system design aims for higher performance, the physical dimensions of the channels are continuously decreasing. With TSV diameter of less than 10 μm and pitch of several tens of micrometers, the I/O count has increased up to the order of tens of thousands for wide bandwidth data transmission. However, without highly precise fabrication process, such small structures are susceptible to a variety of defects. For the first time, in this paper, we propose a noninvasive defect analysis method for high-speed TSV channel. With designed and fabricated test vehicles, the proposed method is demonstrated with S-parameter and time-domain reflectometry measurement results. In addition, we present equivalent circuit models of TSV daisy-chain structures, including the circuit components for open defect and short defect. With characterized dominant factors in each frequency range, S11 is analyzed to distinguish and locate the defects by the amount of capacitance, resistance, and inductance that the signal experiences. S-parameter measurement sufficiently allows high-frequency defect analysis of TSV channel without destroying the test sample. We experimentally verified the accuracy of the suggested model by comparing the S-parameter results from circuit simulations and measurements. Finally, the model is modified to discuss the effects of open defect and short defect on the electrical characteristics of TSV channel.

Equivalent Circuit Modeling in Time Domain of the Hysteresis of Magnetic Materials

This paper proposes a numerical solution of the nonlinear equations that describes the hysteretic behavior of ferromagnetic materials. From the proper definition and solution of these equations, an equivalent circuit model for a ferromagnetic core is developed and proposed. The results obtained from the equivalent circuit are compared with those obtained by a rigorous numerical solution.

Novel De-Embedding Methodology and Broadband Microprobe Measurement for Through-Silicon Via Pair in Silicon Interposer

In this paper, a novel de-embedding methodology is proposed for through silicon via (TSV) characterization by using a set of simple yet efficient test patterns. For all the test patterns, full wave models are developed and the electrical performance of the test patterns is analyzed thoroughly. Furthermore, broadband measurements are performed for the test patterns to verify the accuracy of the developed full wave models up to 40 GHz. Correlation between measurement and simulation results is discussed after optimizing the full wave models based on scanning electron microscope measurement. Analysis of measurement error is available as well. The proposed de-embedding method is applied to both the simulation and measurement results to extract the electrical characteristics of the TSV pair. Good agreement between the de-embedded results with analytical solution and the full-wave simulation for a standalone TSV pair indicates that the proposed de-embedding method works effectively up to 40 GHz. Finally, sensitivity analysis with regard to manufacturing tolerance of the test patterns to the final de-embedded results is performed.