Complex ICs Research Articles

IC power delivery

Modern IC power delivery systems encompass large on-chip passive power grids and active on-chip or off-chip voltage converters and regulators. While there exists little work targeting on holistic design of such complex IC subsystems, the optimal system-level design of power delivery is critical for achieving power integrity and power efficiency. In this article, we conduct a systematic design analysis on power delivery networks that incorporate Buck Converters (BCs) and on-chip Low-Dropout voltage regulators (LDOs) for the entire chip power supply. The electrical interactions between active voltage converters, regulators as well as passive power grids and their influence on key system design specifications are analyzed comprehensively. With the derived design insights, the system-level codesign of a complete power delivery network is facilitated by a proposed automatic optimization flow in which key design parameters of buck converters and on-chip LDOs as well as on-chip decoupling capacitance are jointly optimized. The experimental results demonstrate significant performance improvements resulted from the proposed system cooptimization in terms of achievable area overhead, supply noise and power efficiency. Impacts of different decoupling capacitance technologies are also investigated.

Results of 65 nm pixel readout chip demonstrator array

Complex and challenging instrumentation projects (LHC upgrades, HL LHC, new Detector concepts) will require the adoption of ever more empowering and complex IC technologies. We clearly see that by moving only two nodes from the current 130 nm CMOS to 65 nm, substantial processing power could be embedded in the front-end system. We have designed and fabricated a prototype pixel readout chip to explore 65 nm CMOS as a potential integrated circuit technology for future particle physics applications. Not only the reported functional test results are very encouraging, but we also found that the process is fundamentally tolerant to radiation doses higher than 600 Mrad.

Smarter ICs

This article presented the possibilities of making microwave and mm-wave ICs more intelligent through a combination of established Si/SiGe BiCMOS technologies, which allow for complex ICs combining a multitude of high-speed analog and digital functions, and RFMEMS processing tightly integrated with the baseline BiCMOS technology. The addition of RFMEMS switches and integrated antennas enhanced by micromachining especially pays off at millimeter waves, where chip-to-board interconnects become increasingly cumbersome, and RFMEMS reconfiguration switches offer unparalleled low loss, high isolation, and high linearity.

NOC: QOS Metrics Modelling And Analysis Based On Dynamic Routing

Increasing heterogeneous software and hardware blocks constitute complex ICs known as System on Chip (SoC). These blocks are conceived as intellectual property (IP) cores. Designers are developing SoCs by using IP cores reuse, which include interconnection architecture and interface to peripheral devices.Because of the SoC growing complexity, some researchers tend to concentrate more on the communication rather than the computation aspect. This area of research has leading to the Network on Chip (NoC) Concepts.The research domain of NoC has many applications needing high communication performances. Therefore NoC offers attractive solutions to these applications.One of the goals of NoC technology is to maintain a required Quality of Service (QoS), defined in terms of acceptable parameters values.This paper proposes a presentation of QoS metrics model based on QoS parameters such as Endto-End Delays (EED) and throughputs (Thp), for different applications. This study is based on dynamic routing simulation of a 4x4 mesh NoC behaviour under three communications processes namely TCP, VBR and CBR.

Circuit Level Modeling Methodology of Parasitic Substrate Current Injection from a High-Voltage H-bridge at High Temperature

In this paper, a modeling methodology is validated based on an enhanced model of the diode, that we have developed to simulate substrate current coupling mechanisms on a typical H -bridge structure. An equivalent schematic based on an enhanced model of the diode was previously proposed to account for minority and majority carrier propagation in the substrate and implemented in Verilog-A code. In this study, the injected parasitic substrate current from high-voltage MOSFET's structure is simulated in a circuit-level simulator and with a finite element method, as well. Both are compared to measurements and confirm a very good agreement up to 400 K. Not only the simulation resources needed by the proposed equivalent schematics are greatly reduced with regard to the finite element approach, but this circuit-level modeling methodology is fully compatible with Spice-like simulations of complex ICs.

SPHERICAL HALL ALGEBRAS OF CURVES AND HARDER-NARASIMHAN STRATAS

We show that the characteristic function <TEX>$1S_{\underline{\alpha}}$</TEX> of any Harder-Narasimhan strata <TEX>$S{\underline{\alpha}}\;{\subset}\;Coh_X^{\alpha}$</TEX> belongs to the spherical Hall algebra <TEX>$H_X^{sph}$</TEX> of a smooth projective curve X (defined over a finite field <TEX>$\mathbb{F}_q$</TEX>). We prove a similar result in the geometric setting: the intersection cohomology complex IC(<TEX>${\underline{S}_{\underline{\alpha}}$</TEX>) of any Harder-Narasimhan strata <TEX>${\underline{S}}{\underline{\alpha}}\;{\subset}\;{\underline{Coh}}_X^{\underline{\alpha}}$</TEX> belongs to the category <TEX>$Q_X$</TEX> of spherical Eisenstein sheaves of X. We show by a simple example how a complete description of all spherical Eisenstein sheaves would necessarily involve the Brill-Noether stratas of <TEX>${\underline{Coh}}_X^{\underline{\alpha}}$</TEX>.

Structure and spectroscopy of diorganotin(IV) complexes derived from N′-(2-hydroxy-3-methoxybenzylidene)benzohydrazide

Three new diorganotin(IV) complexes of the general formula R 2Sn[3-(OMe)-2-OC 6H 3CH N–N C(O)Ph] (R = Ph, Ia; R = Me, Ib; R = n-Bu, Ic) have been synthesised from the corresponding diorganotin(IV) dichlorides and the ligand, N′-(2-hydroxy-3-methoxybenzylidene)benzohydrazide in methanol at room temperature in the presence of trimethylamine. All the complexes have been characterized by elemental analysis, IR and 1H, 13C, 15N, 119Sn NMR spectra, and their structures have been confirmed by single crystal X-ray diffraction analysis of one representative compound Ia. Complex Ia crystallises in the orthorhombic system, space group Pna2 1 with a = 12.424(5), b = 9.911(5), c = 18.872(5) Å; Z = 4. The ligand N′-(2-hydroxy-3-methoxybenzylidene)benzohydrazide (H 2L) coordinates to the metal centre in the enolate form via the phenolic O, imino N and enolic O atoms. In Ia, the central tin atom adopts a distorted trigonal bipyramidal coordination geometry with the oxygen atoms in axial positions, while the imino nitrogen atom of the Schiff base and the two phenyl groups occupy the equatorial sites. The δ( 119Sn) values for the complexes Ia, Ib and Ic are −327.3, −151.7 and −187.2 ppm, respectively, thus indicating penta-coordinated Sn centres in solution.

Temperature-aware computing

Temperature-aware techniques have established themselves as crucial steps during the design and operation of new complex ICs (e.g. dual-core microprocessors) in order to protect the ICs against high temperatures that may drastically reduce their lifetime or even render them inoperable. These techniques have been developed after it became clear that power-aware techniques and low-power design are insufficient since they still allowed hotspots to develop in the chip with temperatures considerably higher than the average temperature. The goal of this paper is to provide an overview of the state-of-the-art of temperature-aware computing. After a brief introduction, we present the current approaches to measuring the temperature of a circuit during its operation and to estimating, during the design phase, the maximum temperature that the circuit will experience. We then survey the known techniques for designing a chip with lower maximum temperature. This is followed by reviewing the currently employed run-time temperature management techniques. This paper presents a thorough review of the research done in the past decade or so in the field of thermal-aware computing and lists most of the relevant journal and conference papers on this topic.

THE EVOLUTION OF CIRCUMSTELLAR DISKS SURROUNDING INTERMEDIATE-MASS STARS: IC 1805

We report the results of a study of the intermediate and high mass stars in the young, rich star-forming complex IC 1805, based on a combination of optical, near-infrared, and mid-infrared photometry, and classification spectra. These data provide the basis for characterizing the masses and ages for stars more massive than ~2 Msun and enable a study of the frequency and character of circumstellar disks associated with intermediate- and high-mass stars. Optically thick accretion disks among stars with masses 2 < M/Msun <4 are rare (~2% of members) and absent among more massive stars. A larger fraction (~10%) of stars with masses 2 < M/Msun < 4 appear to be surrounded by disks that have evolved from the initial optically thick accretion phase. We identify four classes of such disks. These classes are based on spectral energy distributions (SEDs) of excess emsission above photospheric levels: disks that are (1) optically thin based on the magnitude of the observed excess emission from 2 to 24 um; (2) optically thin in their inner regions (r< 20 AU) and optically thick in their outer regions; (3) exhibit empty inner regions (r < 10 AU) and optically thin emission in their outer regions; and (4) exhibit empty inner regions and optically thick outer regions. We discuss, and assess the merits and liabilities of, proposed explanations for disks exhibiting these SED types and suggest additional observations that would test these proposals.

Properties of Digital Switching Currents in Fully CMOS Combinational Logic

In this paper, we present a model to derive statistical properties of digital noise due to logic transitions of gates in a fully CMOS combinational circuit. Switching activity of logic gates in a digital system is a deterministic process, depending on both circuit parameters and input signals. However, the huge number of logic blocks in a complex IC makes digital switching a cognitively stochastic process. For a combinational logic network, we can model digital switching currents as stationary shot noise processes, deriving both their amplitude distributions and their power spectral densities. From the spectra of digital currents, we can also calculate the spectral components and the rms value of disturbances injected into the on-chip power supply lines. The stochastic model for switching currents has been validated by comparing theoretical results with circuit simulations.

Test Access Port &amp; Scan Based Technique of In-System Timing Extraction and Control

Historically, most Printed Circuit Board (PCB) testing was done using bed-of-nail in-circuit test equipment. The progress in the field of miniaturization and integration density has possible to design very complex PCBs, which presents very high testability requirements. Boundary scan is now the most promising technology for testing high complexity PCBs. This paper presents scan-based test access port standard for testing complex ICs and also presents a method which allow the extraction of fine-grained timing information using Test Access Port (TAP).

Complex Systems Failure Analysis Challenges

Abstract This article presents a failure analysis workflow tailored for complex ICs and device packages. The FA flow determines the root cause of failures using nondestructive analysis and advanced sample preparation techniques. The nondestructive tests typically used are X-ray radiography, scanning acoustic microscopy, time domain reflectometry, and magnetic current imaging. To gain access to interconnect failures, laser ablation is used, typically in combination with chemical etching to finish the decapsulation process. Repackaging is also part of the FA flow and is briefly discussed.

Dealing with early life failures

D&T editor in chief Tim Cheng discusses the industry's struggle to screen latent defects for complex ICs. He also welcomes two new editors to the D&T editorial board.

Application of vitreous and graphitic large-area carbon surfaces as field-emission cathodes

Numerous carbon bulk or thin-film materials have been used as field-emission cathodes. Most of these can be made into large-area and high-current field-emission cathodes without the use of complex IC fabrication techniques. Some of these exhibit low-extraction field, low work-function, high ruggedness, chemical stability, uniform emission, and low-cost manufacturability. A comparison of all of these materials is presented. Two viable cathode materials, reticulated vitreous carbon (RVC) and graphite paste are examined here and compared.

New palladacyclic complexes with pyridylphosphine ligands: crystal structures of [Pd(Azb)(Ph 2POCH 2Py-P,N)][PF 6] and [Pd(Phpy)(Ph 2PNHPy-P,N)][PF 6

The synthesis of palladacyclic derivatives with the hybrid pyridylphosphine ligands Py(CH 2)OPPh 2 ( a) and PyNHPPh 2 ( b) in a neutral P,N-chelating coordination mode has been achieved. Treatment of selected chloride-bridged cyclometallated precursors [Pd(C ∧N)(μ-Cl)] 2 [C ∧N = 2-pyridinin-phenyl Phpy, I-compounds; 7,8-benzoquinolyl Bzq, II-compounds; phenylazophenyl Azb, III-compounds or 2-(2-oxazolinyl)phenyl Phox, IV-compounds] with a or b in the presence of stoichiometric KPF 6 gave the mononuclear derivatives Ia– IVa and Ib– IVb. The crystal structures of compounds [Pd(Azb)(Ph 2POCH 2Py-P,N)][PF 6] ( IIIa) and [Pd(Phpy)(Ph 2PNHPy-P,N)][PF 6] ( Ib) have been determined. The new palladacyclopentadiene precursor [Pd{C 4COOMe 4}(CH 3CN) 2] ( V) has been prepared starting from the polymeric complex [Pd{C 4COOMe 4}] n . Its usefulness in the preparation of new derivatives has been tested by means of the straightforward reaction with ligands ( a) or ( b) to give mononuclear compounds [Pd{C 4(COOMe) 4}(Ph 2POCH 2Py-P,N)] ( Va) and [Pd{C 4(COOMe) 4}(Ph 2PNHPy-P,N)] ( Vb). The reactions of hydroxo-bridged precursors [Pd(C ∧N)(μ-OH)] 2 or [Pd 2{C 4(COOMe) 4} 2 (μ-OH) 2][NBu 4] 2 with PyNHPPh 2 afforded mononuclear complexes Ic– Vc ( PyNPPh 2 - = c ligand ) in which a less common anionic P,N-binding mode is forced as a result of ligand deprotonation. The new complexes were characterised by partial elemental analyses and spectroscopic methods (IR, FAB, 1H and 31P{ 1H} NMR).

Porosity-Aware Buffered Steiner Tree Construction

In order to achieve timing closure on increasingly complex IC designs, buffer insertion needs to be performed on thousands of nets within an integrated physical synthesis system. Modern designs may contain large blocks which severely constrain the buffer locations. Even when there may appear to be space for buffers in the alleys between large blocks, these regions are often densely packed or may be needed later to fix critical paths. Therefore, within physical synthesis, a buffer insertion scheme needs to be aware of the porosity of the existing layout to be able to decide when to insert buffers in dense regions to achieve critical performance improvement and when to utilize the sparser regions of the chip. This work addresses the problem of finding porosity-aware buffering solutions by constructing a "smart Steiner tree" to pass to van Ginneken's topology-based algorithm. This flow allows one to fully integrate the algorithm into a physical synthesis system without paying an exorbitant runtime penalty. We show that significant improvements on timing closure are obtained when this approach is integrated into a physical synthesis system.

Guest editors' introduction: Speed test and speed binning for complex ICs

Presents the guest editorial for this issue of the publication.

The influence of guests on host molecular conformation: the structures of solvates of 5-(morpholinemethyl)-3-[(4-chlorobenzylidene)amino]-2-oxazolidinone

Three solvates of 5-(morpholinemethyl)-3-[(4-chlorobenzylidene)amino]-2-oxazolidinone ( I) have been prepared and their solid-state structures analysed. In the semihydrate crystals ( Ia), the base is observed in the usual overall extended conformation. The dihydrate ( Ib) and formamide complex ( Ic) are isostructural and share the same general packing of base molecules, which adopt a bent conformation with helical catemers of solvent; the differences are mainly in the number of host–guest interactions. Both crystals were formed exclusively during the deprotonation of I HCl in polar solvents. In crystal lattices, the 5-(morpholinemethyl)-3-(aminomethylene)-2-oxazolidinone fragment of I is a principal synthon in intermolecular host–host and host–guest contacts. It is usually an acceptor in the Y–H⋯O and/or Y–H⋯N [Y=O, N, C] bonds, and a chelating donor to the C–H⋯X [X=O, Cl, Cl −] bonds.

Design for Debug

For large, complex ICs, engineers need efficient techniques for debugging first silicon. The system presented here consists of an on-chip debug infrastructure and supporting debugger software,which...

Design for debug: catching design errors in digital chips

For large, complex ICs, engineers need efficient techniques for debugging first silicon. The system presented here consists of an on-chip debug infrastructure and supporting debugger software,which interacts with the infrastructure to make the chip's features accessible through a serial interface.