Philippe Descamps

Magnetic microscopy for ICs failure analysis : comparative case studies using SQUID, GMR and MTJ systems

Magnetic field based techniques have shown great capabilities for investigation of current flows in ICs. After reviewing the performances of SQUID, GMR (hard disk head technologies) and MTJ existing sensors, we present results obtained on various case studies. This comparison shows the benefit of each approach according to each case study (packaged devices, flip-chip circuits,...). Finally we discuss the obtained results to classify current techniques, optimal domain of applications and advantages.

Isolating failing sites in IC packages using time domain reflectometry: Case studies

This paper deals with Time Domain Reflectometry (TDR) technique with the aim to confirm that this tool should not be kept away from a non-destructive failure analysis process flow. An improvement of known comparative TDR methodology, the sequential comparative method, is introduced and several case studies illustrate its better efficiency to isolate complex packaging defects. Also, main limitations of the technique are studied and several hardware improvements are proposed, especially in terms of spatial resolution.

Analytic description of scanning capacitance microscopy

Scanning capacitance microscopy (SCM) is a doping profile extraction using a nanometric probe as a gate of a metal-oxide-semiconductor (MOS) structure and measuring the differential capacitance. Thanks to the complete MOS equations, the authors propose in this article a description of the differential capacitance calculation. This analytic presentation is based on the solution of the Poisson-Boltzmann equation in the unidimensional mode in silicon and a decomposition of the probe in elementary rings giving capacitance from the surface probe and silicon. As [dC(Vg)∕dVg]α(dΨs∕dVg), this presentation yields to the importance of the surface band bending Ψs at the oxide-semiconductor interface. The dC(Vg)∕dVg calculation shows that the contact of the probe with the sample has its main contribution over a few nanometers. Results are discussed to obtain a calibration of a SCM probe available in a large range of doping and voltage and to assess the dC(Vg)∕dVg signal after erosion of the probe by successive scans.

Reconfigurable sensors for extraction of dielectric material and liquid properties

This paper proposes an analysis and modeling of a reconfigurable sensor for the non-destructive remote extraction and monitoring of dielectric material and liquid properties, towards substance identification or distribution cartography.

Broadband characterization of dielectric materials from RF, millimeter-wave to THz frequencies accounting for anisotropy

In this paper, experimental characterization of dielectric materials from RF, mm-Wave to THz frequencies accounting for Anisotropy is presented. Broadband extraction of complex permittivity values and dissipation factors for various materials is proposed. A more specific focus is particularly done on a Liquid crystal Polymer (LCP) and passive components on BiCMOS technology with Deep-Trench-Insulator patterns (DTI). Perspectives for the derivation of scalable broadband models fulfilling Kramers-Kronig relationships for use in Time-Domain and Frequency-Domain modeling analysis are drawn.

High-Quality varactors and Schottky-Diodes in SiGe:C Technology for mm-Wave and THz applications

This paper presents the design and experimental characterization of High-Quality varactors and Schottky Diodes in SiGe:C Technology. A new layout topology for differential varactor is proposed to significantly improve its quality factor up to the Ka band. This new layout topology addresses the typical trade-off that designers often face between the quality factor and the tuning range. 2x improvement of the quality factor up to 30 GHz over conventional layout topology made of multi fingers is demonstrated. On the other side, special care has been taken to minimize parasitic capacitance between anodes to keep the tuning range stable. Measured VCO with this new type of varactor shows a reduction of 2 dB in the Phase Noise at 1 MHz from the carrier. Silicon-based Schottky Diodes arrays with Cut-Off frequencies in the THz domain are designed and fabricated. Concurrent optimization of Schottky Diode arrays geometry and electrical performances (Cutoff frequency, parasitic, Quality-factor, Sensitivity, Responsiveness, etc.) is carried out based on careful modeling and experimental characterizations. Analysis of the Schottky Diode arrays including sweep in DC-biasing conditions to control non-linearities is studied. Detection mechanisms related to the non-linear behavior are studied and figures of merit are introduced for their analysis.

Failure localization in IC packages using time domain reflectometry: technique limitations and possible improvements

Our case study has shown the efficiency of isolating failing sites (shorts, opens) in IC packages using TDR and especially sequential comparative TDR analysis, which allowed to overcome some of TDR hardware limitations and to identify the different regions of the DUT. Currently, its possible to increase the bandwidth of the main standard TDR sources available on the market up to 70 GHz, but the main limitation is due to TDR probes which best bandwidth only reaches 20 GHz. Anyway, TDR technique has already proved to definitively take up its own place in the non-destructive failure analysis flow of FA labs beside SCAT and x-ray ones for most of common IC packages used in semiconductors industry.

Bonding-Wire-Geometric-Profile-Dependent Model for Mutual Coupling Between Two Bonding Wires on a Glass Substrate

The dependence of self-inductance and mutual inductance on bonding wire (BW) geometric profile has been studied in several papers. This paper will present a method using a BW-geometric-profile-dependent term to include this dependence in a simple model of BWs. The model element values will be calculated only from geometric dimensions. An experimental structure of two BWs in parallel planes has been fabricated based upon glass substrate technique for verification. A good agreement was obtained up to 8 GHz in comparison to electromagnetic simulation and measurement.

Electromagnetic modeling and experimental characterization of dielectric material and liquid properties from RF to THz

This paper proposes a complementary multi-physics material analysis approach based on broadband dielectric characterization and Atomic Force Microscopy. In the prospect of integrated dielectric sensor design, this approach was applied to polymers commonly employed by various emerging technologies.

Modelling of an inductor on SiGe: From the measurement to the equivalent scheme

We propose a methodology to extract models for inductors from measurements. The methodology is applied to a one-turn solenoid and to spiral inductor.