Advances in memory density and capacity have had the consequence of increasing the probability of memory faults. For this reason, redundancy analysis (RA) and repair are used as effective solutions to improve memory yield. However, as the growth of the number of memory cells increases, it causes increase of the number of faulty cells and results in increase of difficulty of fault analysis. Although various RA methodologies have been proposed, most of them require a long analysis time or fast analysis speed without achieving a 100% normalized repair rate. Furthermore, research on conventional RA methodologies has not included effective early termination methods. Therefore, in this paper, fault group pattern matching (FGPM) is proposed for high speed RA with an effective early termination method. It can achieve very fast analysis with a 100% normalized repair rate. Additionally, it can finish the analysis rapidly by the proposed early termination method when a memory cannot be repaired. Experimental results demonstrate that the FGPM is highly effective in reducing analysis time with the achievement of a 100% normalized repair rate. In addition, the effectiveness of the proposed early termination is shown.
The way in which we interact with our cars is changing, driven by the increased use of mobile devices, cloud-based services, and advanced automotive technology. In particular, the requirements and market demand for the Internet of Things (IoT) device-connected vehicles will continuously increase. In addition, the advances in cloud computing and IoT have provided a promising opportunity for developing vehicular software and services in the automotive domain. In this paper, we introduce the concept of a home IoT connected vehicle with a voice-based virtual personal assistant comprised of a vehicle agent and a home agent. The proposed concept is evaluated by implementing a smartphone linked with home IoT devices that are connected to an infotainment system for the vehicle, a smartphone-based natural language interface input device, and cloud-based home IoT devices for the home. The home-to-vehicle connected service scenarios that aim to reduce the inconvenience due to simple and repetitive tasks by improving the urban mobility efficiency in IoT environments are substantiated by analyzing real vehicle testing and lifestyle research. Remarkable benefits are derived by making repetitive routine tasks one task that is executed by a command and by executing essential tasks automatically, without any request. However, it should be used with authorized permission, applied without any error at the right time, and applied under limited conditions to sense the habitants’ intention correctly and to gain the required trust regarding the remote execution of tasks.
13 January 2023 in IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
As the demand for data-intensive analytics has increased with the rapid advance in artificial intelligence (AI), various AI accelerators have been proposed. However, as AI-based solutions have been adapted to applications requiring accuracy and reliability, the reliability of them has become a critical issue. For this reason, self-test and self-recovery for AI accelerator (STRAIT) is proposed in this article. It facilitates self-test, self-diagnosis, and self-recovery by utilizing the structural and operational characteristics of systolic array in AI accelerator. The proposed self-test is progressed using scan chains composed of functional paths and can achieve a 100% test coverage (for both stuck-at and transition-delay faults) with a small number of test patterns and reduced test power. The proposed self-diagnosis is progressed with the proposed self-test in real time and allows accurate fault localization with fault type analysis. The proposed self-recovery is progressed using efficient pruning for faulty processing elements with weight allocation, and the reliability of AI accelerators can drastically increase with negligible performance degradation. However, STRAIT can be implemented with a small area overhead.
As the technology node of the dynamic random-access memory (DRAM) continues to decrease below the 10-nm-class, bit-cell failures due to the external environments have increased. As a result, DRAM vendors perform post package inspections to provide fault-free DRAMs to the end customers. However, post package inspections require considerable test costs. To overcome this issue, an in-DRAM built-in self-test (BIST) mechanism is implemented in this study as an alternative solution. Herein, we propose compact and high test-coverage features for the in-DRAM BIST that to resolve the area problem when applied to a commodity DRAM. The proposed BIST secures the same test coverage with a shorter time than the conventional BIST. The proposed BIST reduces the test time by 52% of the DDR BIST in functions with the same test coverages. Further, the implemented BIST can achieved an area overhead of 0.051% based on a 16Gb DDR4 DRAM in the second generation of the 10-nm-class DRAM process.
21 September 2016 in IEEE Transactions on Very Large Scale Integration (VLSI) Systems
Memory capacity continues to increase, and many semiconductor manufacturing companies are trying to stack memory dice for larger memory capacities. Therefore, built-in redundancy analysis (BIRA) is of utmost importance because the probability of fault occurrence increases with a larger memory capacity. A traditional spare structure that consists of simple rows and columns is somewhat inadequate for multiple memory blocks BIRA because the hardware overhead and spare allocation efficiency are degraded. The proposed BIRA uses various types of spares and can achieve a higher yield than a simple row and column spare structure. Herein, we propose a BIRA that can achieve an optimal repair rate using various spare types. The proposed analyzer can exhaustively search not only row and column spare types but also global and local spare types. In addition, this paper proposes a fault-storing content-addressable memory (CAM) structure. The proposed CAM is small and collects faults efficiently. The experimental results show a high repair rate with a small hardware overhead and a short analysis time.
22 August 2018 in IEEE Transactions on Reliability
A three-dimensional (3-D) integration technology involving the use of a through-silicon-via (TSV) offers advantages such as low power consumption, small form factor, and large bandwidth. However, owing to the incompleteness of the 3-D manufacturing process, TSVs may exhibit some inherent defects; hence, switching and shifting repairing methods have been proposed. These methods repair the TSV faults by rerouting the signals of the faulty TSVs to the other signal TSVs or redundant TSVs using a simple repair algorithm. However, if one TSV exhibits a defect during its manufacturing process, the probability of multiple defects occurring in the TSVs neighboring the FTSV increases, i.e., the TSV defects tend to be clustered. Therefore, recently proposed repair solutions, such as ring/router-based repair architectures, have focused on clustered TSV faults. However, the implementation of these existing repair solutions for clustered faults involves an extremely high hardware overhead. This study proposes a TSV redundancy architecture to repair clustered TSV faults with a high repair rate and low hardware overhead. The proposed architecture divides the TSVs into several groups and connects the TSVs of each group using a 2:1 multiplexer chain. Simulation results show that the proposed architecture exhibits a repair rate of 98.52% for uniformly distributed faults and 69.86% for highly clustered faults. These repair rates are higher than those of other TSV redundancy architectures and the difference in the repair rate becomes even greater if the faults are more clustered. Moreover, the approach yields a 58.55% reduced area as compared to that of the router-based redundancy architecture, which also targets the repair of clustered faults.