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Cryptography hardware is vulnerable to side-channel (SC) attacks on power supply current flow and electromagnetic (EM) emission. This article proposes simulation-based power and EM side-channel leakage analysis (SCLA) techniques on a cryptographic integrated circuit (IC) chip in system level assembly. SCLA measures SC leakage metrics including T-score, SC leakage score, and the number of measurement traces to disclosure, leveraged by a secure system-on-chip design flow toward SC attack resiliency and SC leakage sign off. Power SCLA features the tracking of security sensitive registers within cryptographic logic paths and the automatic assignments of probe points on associated physical power nets. Power supply current traces are efficiently simulated for the large set of input payloads, with direct vector-based and vector-less random switching controls. EM SCLA evaluates magnetic fields created by every piece of metal wiring in metal stacks where power supply current of cryptographic processing flows. The EM emission and EM SCLA from the backside Si surface of an IC chip in flip-chip packaging are experimentally examined with a 0.13 µm test chip. The proposed simulation-based SCLA exhibits the SC leakage metrics of on-chip location and direction dependency as accurately as in the measurements. [ABSTRACT FROM AUTHOR]

Purpose This paper aims to demonstrate the improved functionality of additive manufacturing technology provided by combining multiple processes for the fabrication of packaged electronics.Design/methodology/approach This research is focused on the improvement in resolution of conductor deposition methods through experimentation with build parameters. Material dispensing with two different low temperature curing isotropic conductive adhesive materials was characterised for their application in printing each of three different conductor designs, traces, z-axis connections and fine pitch flip chip interconnects. Once optimised, demonstrator size can be minimised within the limitations of the chosen processes and materials.Findings The proposed method of printing z-axis through layer connections was successful with pillars 2 mm in height and 550 µm in width produced. Dispensing characterisation also resulted in tracks 134 µm in width and 38 µm in height allowing surface mount assembly of 0603 components and thin-shrink small outline packaged integrated circuits. Small 149-µm flip chip interconnects deposited at a 457-µm pitch have also been used for packaging silicon bare die.Originality/value This paper presents an improved multifunctional additive manufacturing method to produce fully packaged multilayer electronic systems. It discusses the development of new 3D printed, through layer z-axis connections and the use of a single electrically conductive adhesive material to produce all conductors. This facilitates the surface mount assembly of components directly onto these conductors before stereolithography is used to fully package multiple layers of circuitry in a photopolymer. [ABSTRACT FROM AUTHOR]

With the rapid growth of the microelectronic packaging market, it is necessary to increase the throughput and reduce the cost of flip chip. Driven by these evolutions, a novel revolving-turret chip transferring (RTCT) technology is introduced to implement high-throughput flip chip packaging. The unnecessary time delays of packaging processes could be eliminated in the RTCT technology due to its parallel manner of motions. In order to analyze the packaging efficiency, the layout and movement sequence of the packaging system are studied, and a calculation model of packaging efficiency is proposed. Furthermore, the effects of the critical parameters (the horizontal and the vertical spacing of antennas and the maximum velocity and acceleration of the turret-type head) on packaging efficiency are investigated to search out the optimal parameters combination. To verify the performance of the RTCT technology under optimal parameters combination, two cases are implemented and compared. The results show that due to parallel motions of processes, unnecessary delays affecting the packaging efficiency have been reduced, and the packaging efficiency of ALN-9714 inlay could be more than 35k chips per hour. In addition, compared with the conventional flip chip packaging process, the RTCT technology is more effective in packaging the chips on antennas with multicolumn layout and small horizontal spacing. [ABSTRACT FROM AUTHOR]

Interfacial reactions in Sn/Ni-4.5 wt.%Si and Sn-Cu/Ni-4.5 wt.%Si couples at 250°C, and Sn-Ni-Si ternary phase equilibria at 250°C were investigated in this study. Ni-Si alloys, which are nonmagnetic, can be regarded as a diffusion barrier layer material in flip chip packaging. Solder/Ni-4.5 wt.%Si interfacial reactions are crucial to the reliability of soldered joints. Phase equilibria information is essential for development of solder/Ni-Si materials. No ternary compound is present in the Sn-Ni-Si ternary system at 250°C. Extended solubility of Si in the phases NiSn and NiSn is 3.8 and 6.1 at.%, respectively. As more Si dissolves in these phases their lattice constants decrease. No noticeable ternary solubility is observed for the other intermetallics. Interfacial reactions in solder/Ni-4.5 wt.%Si are similar to those for solder/Ni. Si does not alter the reaction phases. No Si solubility in the reaction phases was detected, although rates of growth of the reaction phases were reduced. Because the alloy Ni-4.5 wt.%Si reacts more slowly with solders than pure Ni, the Ni-4.5 wt.%Si alloy could be a potential new diffusion barrier layer material for flip chip packaging. [ABSTRACT FROM AUTHOR]

Microelectromechanical systems (MEMS)-type double helix chip-level electrical interconnect structures are fabricated and characterized in this paper. Due to their springlike structure, double helix interconnects have the potential to provide large mechanical compliance to compensate for nonidealities, such as nonplanarity and thermal expansion mismatch between silicon chips and substrates. A double helix configuration provides for structures with a high volumetric density of conductor for enhanced current carrying capability. The fabrication process is compatible with wafer-level fabrication and packaging. Instead of using solder to form semipermanent interconnections, the double helix interconnects use pressure to make electrical connection and provide sufficiently low resistance (~35 ± 15 mΩ). Large arrays of double helix structures have been fabricated and characterized with excellent yield. The mechanical and electrical models of the structures are presented. Reworkability tests were performed and the structures show a consistent resistance over 50 remating cycles. [ABSTRACT FROM AUTHOR]

This study investigated the influence of different injection types, such as I-type, L-type, and U-type, on the dynamic behavior of capillary-driven encapsulation flows for a commercially available flip chip. The dynamic filling behavior of underfill encapsulation was visualized experimentally, and numerical simulations were conducted for three-dimensional flows in a flip chip package by using commercial software (ANSYS FLUENT Ver. 13.0). Numerical results were compared with experimental data for the filling time and the rate of change in underfill volume fraction with different injection types. At the early stage of underfill injection, the estimated flow characteristics exhibited high capillary acceleration that rapidly decreased with time, which indicates that capillary force was dominant in underfill encapsulation. The capillary pressure drop effect was dominant at the early stage. Thus, the injection method for underfill encapsulation inside the flip chip should be carefully controlled for faster and more stable encapsulation to avoid void formation in the chips. [ABSTRACT FROM AUTHOR]

Electronics packaging based on stress-engineered spring interconnects has the potential to enable integrated IC testing, fine pitch, and compliance not readily available with other technologies. We describe new spring contacts which simultaneously achieve low resistance (<100~m\Omega) and high compliance (>30~\mum) in dense 2-D arrays (180–180-\mum pitch). Mechanical characterization shows that individual springs operate at approximately 150-\muN force. Electrical measurements and simulations imply that the interface contact resistance contribution to a single contact resistance is <40~m\Omega. A daisy-chain test die consisting of 2844 contacts is assembled into flip-chip packages with 100% yield. Thermocycle and humidity testing suggest that packages with or without underfill can have stable resistance values and no glitches through over 1000 thermocycles or 6000 h of humidity. This paper suggests that integrated testing and packaging can be performed with the springs, enabling new capabilities for markets such as multichip modules. [ABSTRACT FROM AUTHOR]

This paper focuses on the packaging process and assembly and interlayer dielectrics (ILD) structural stability including mechanical simulation with polymer-encapsulation and redistribution process for 150-µm pitch Pb-free flip chip packaging of low-k/Cu interconnects. Chemical vapor deposition (CVD) type low-k test vehicles with four Cu layers were fabricated using Cu dual damascene process. Polymer encapsulation and metal redistribution (RDL) technology were applied using wafer integration technology to minimize the stress from the solder bump pad to low-k ILD. This polymer encapsulated dicing line (PEDL) was introduced and the result of investigation discussed. Finite element method (FEM) mechanical simulations are per- formed for RDL approach, normal direct bumping, and PEDL. According to the results with shear loading, RDL approach showed less stress than that of direct bumping at the solder joint. Simulation indicated the die corner stress is reduced significantly on chip with PEDL as compared to that without PEDL. For copper postinterconnects, cost-effective and thick photoresist process was developed and optimized for electro Cu plating and solder was deposited on the top of Cu post. Bump shear test was carried out to evaluate the bump quality and failures were analyzed. After flip chip assembly with Cu/low-k devices having via-chain and daisychain interconnects, various JEDEC standard reliability tests were carried out and failure analysis was performed. [ABSTRACT FROM AUTHOR]

This paper designs a new multilayered particle anisotropic conductive film (ACF) compound. Using the particle-reinforced composite model and probability theory, the novel ACF compound is compared with three traditional ACFs having the same particle volume fraction. The particle-reinforced model applies the concept of bonded and debonded structures in the interfaces between the adhesive resin and the particles. The elastic modulus of the particle-reinforced ACF is a function of the particle volume fraction and the bonded condition. In the failure model, probability theory is used to calculate the probability of opening and bridging. The volume fraction of the conductive particles plays an important role in determining the optimal ACF design. The current results indicate that the flip chip packaging performed using the novel multilayered particle ACF compound (particles distributed in the top/bottom surface layers) exhibits superior particle-reinforcement properties and a lower failure probability than traditional ACFs. The improved understanding of reinforcement mechanisms and failure probability developed by this study facilitates the enhanced design of novel ACF compounds. [ABSTRACT FROM PUBLISHER]

This paper develops a model for predicting the failure probability of flip chip packaging using anisotropic conductive adhesive (ACA). The proposed approach modifies the box model to improve the accuracy of the bridging probability estimation by considering bridging in all directions. In the current failure analysis, probability theory is applied to calculate the probability of both opening and bridging failure. The Poisson distribution is used to calculate the probability of opening in the vertical gap between the pads, while the modified box model is used to estimate the probability of bridging between the pads. The results indicate that the modified box model provides an effective means of accurately estimating the probability of failure. The failure analysis takes the volume fraction of the conductive particles as the major variable in defining the optimal ACA design condition. A V-shaped curve model can be employed to establish an appropriate value of the volume fraction as a function of conductive particle radius, pitch, and pad dimensions such that the overall probability of failure is minimized. [ABSTRACT FROM PUBLISHER]

We demonstrate a shallow ridge waveguide, lumped element electroabsorption modulator (EAM) based on AlInGaAs multiple quantum wells, operating with input powers up to 8 dBm. The device was isolated between two DC controlled sections, using angled etched slots in the waveguide, minimizing optical feedback, while also providing 40-KΩ resistance between devices. The EAM uses a planar isolated pedestal contact with a benzocyclobutene bridge, allowing for a small contact footprint of just 0.024 mm2, while being suitable for flip-chip packaging. The parasitic capacitance was measured to be 19.6 fF, and the EAM has a f3dB bandwidth of 42 GHz. [ABSTRACT FROM PUBLISHER]