Adherence to the ISO 26262 standard requires periodic testing of embedded memories in automobiles, which must be completed within short time windows during normal vehicle operation. This testing must preserve memory contents post-test and integrate test logic seamlessly with system functionality, all while minimizing disruption to vehicle performance. This paper proposes a Memory Built-In Self-Test (MBIST) architecture that addresses these challenges by using a series of short test bursts. The architecture dynamically adjusts the length of each burst based on available memory idle time, ensuring efficient testing without interfering with critical system functions. Additionally, the architecture minimizes hardware overhead by reusing existing resources and introduces a direct access interface for tighter integration with system logic, further enhancing test efficiency and reducing latency.

An increasing number of embedded memory instances, despite lowering the power supply voltage and technology node size, leads to higher power dissipation during the memory test phase when manufacturing a System-on-Chip (SoC). Commonly used manual memory test scheduling techniques need to be replaced with more systematic approaches. The objective is to minimize the test time through concurrent memory testing, resulting in maximization of the dissipated power, but in the way the given power budget is not exceeded. The paper comprises two topics. Firstly, it presents a toolchain aimed at a thorough monitoring of the power dispersed by memory instances and associated Memory Built-In Self-Test (MBIST) instruments. Secondly, several algorithms are proposed that optimize the memory test scheduling for a commercial Design-for-Test (DFT) tool.

Scaling down the transistor size enables a cost-effective high-performing solution in modern semiconductor designs. However, the added complexity of process and extremely small critical three-dimensional spacing of the transistor structure make it more challenging to maintain precise variation control. Defects introduced here can lead to different intermittent behaviors, some of which might not appear as fails during traditional testing procedures but might manifest as a system failure in the field. The emergence of artificial intelligence chip design has introduced high demands for a massive number of multi-cores connected in parallel with a huge memory array size in a chip. This further increases the importance of identifying rare tail events through in-depth diagnosis in advanced nodes. Various sophisticated algorithms have been proposed to improve defect coverage. However, the addition of algorithms may increase test cost tremendously while providing limited benefits for specific fault types which may not happen. Therefore, selecting a smart combination of algorithms that provide enough coverage for the specific product application is essential for cost-effective testing. In this paper, we review the electrical properties of marginal defects inserted in an SRAM device to evaluate test escapes in the latest technology. We also present a new algorithm to improve test coverage efficiency. A commercially available memory BIST tool was used to load a DFT compatible algorithm and operation set for memory test. A commercially available analog simulation tool was used in combination with a novel defect simulation flow to evaluate digital and analog behavior of the device.

Contemporary and emergent automotive systems are heavily populated by complex integrated electronics. The number of safety-critical devices used in advanced driver-assistance systems or autonomous vehicles is growing with high-end models containing hundreds of embedded microcontrollers. Achieving functionally safe automotive electronics requires test solutions that might be costly to engineer. Therefore, to address challenges posed by high-quality and long-term reliability requirements, this article presents low-cost test pattern generation schemes for a scan-based hybrid logic BIST of automotive ICs. It may allow one to optimize test coverage and test time during in-system test applications. The first presented technique deploys a seed-flipping PRPG to periodically complement PRPG stages in a methodical tree-traversal manner. The second scheme is based on a seed-sorting approach that allows additional tradeoffs between test data volume and test coverage. As shown in this article, the proposed schemes can be easily integrated with a test compression environment and deployed in different modes of in-system testing, such as key-off, key-on, and periodic (incremental) online tests. Experimental results obtained for automotive designs and reported herein show improvements in test quality over conventional logic BIST schemes.

Spin-transfer torque magnetoresistive random-access memories (STT-MRAMs) are gradually superseding conventional SRAMs as last-level cache in System-on-Chip designs. Their manufacturing process includes trimming a reference resistance in STT-MRAM modules to reliably determine the logic values of 0 and 1 during read operations. Typically, an on-chip trimming routine consists of multiple runs of a test algorithm with different settings of a trimming port. It may inherently produce a large number of mismatches. Diagnosis of such a sizeable volume of errors by means of existing memory built-in self-test (MBIST) schemes is either infeasible or a time-consuming and expensive process. In this paper, we propose a new memory fault diagnosis scheme capable of handling STT-MRAM-specific error rates in an efficient manner. It relies on a convolutional reduction of memory outputs and continuous shifting of the resultant data to a tester through a few output channels that are typically available in designs using an on-chip test compression technology, such as the embedded deterministic test. It is shown that processing the STT-MRAM output by using a convolutional compactor is a preferable solution for this type of applications, as it provides a high diagnostic resolution while incurring a low hardware overhead over traditional MBIST logic.

Several hard-to-detect faults occurring in read-only memories require complex test algorithms that make it difficult to perform accurate diagnosis in a reasonable time. The primary reason for this is a multitude of reference signatures that need to be stored and compared against the actual data obtained from a ROM-under-test in order to isolate the failing memory sites. This paper presents techniques that facilitate fault diagnosis when deploying complex test algorithms such as GALPAT or Walking 1/0. The new diagnostic techniques reduce processing time and a tester memory size such that it becomes feasible to identify hard-to-detect faults within a memory BIST infrastructure.

The paper presents a high-speed serial interface between external tester and Embedded Deterministic Test (EDT) compression logic hosted by SoC designs. With only a single bidirectional link, the system is capable of feeding distributed heterogeneous cores with hundreds of test channels. Moreover, it synergistically supports EDT bandwidth management to improve the overall test performance. A detailed study indicates a high potential of the serial EDT approach to handle large multicore SoC designs by deploying only a single serial interface and completing the entire test for stuck-at faults in less than one second. Experiments conducted with the help of FPGA -- based evaluation platform confirm feasibility and a high effectiveness of the proposed solution.

In the paper, two methods of ensuring high quality of the memory built-in self-test tools are presented. The described ideas illustrate general methods and are applicable to any commercial memory BIST tool. The first solution describes controller emulation in order to validate each step of the real controller's operations. The second approach presents a way to determine the test algorithms' fault coverage by means of the memory fault simulator. The experimental results show functional benefits and effectiveness of the proposed solutions.

This paper presents a new BIST-based fault diagnosis scheme for non-march tests of complexity O(n^2). It can be used to identify failures in embedded memory arrays using galloping pattern tests. The proposed solution employs scalable and flexible logic to record test responses, with no negative impact on at-speed test. It enables recording of responses produced by failures hard to handle by conventional march tests. This, in turn, allows accurate isolation of memory failures during off-line processing.

This paper presents a novel scheme to address the challenge of identifying failing scan cells from production test responses in the presence of scan compression. The scheme is based on a very simple test response compactor employing orthogonal- spatial and time- signatures. The advantage of this scheme as compared to previous work in this field is the simple and incremental nature of the compaction hardware required. The ability of the scheme to accurately identify failing scan cells from compacted responses has been measured on production fail data from five industrial designs and is reported herein.

This paper presents a novel scheme to address the challenge of identifying failing scan cells from production test responses in the presence of scan compression. The scheme is based on a very simple test response compactor employing orthogonal—spatial and time—signatures. The advantage of this scheme as compared to previous work in this field is the simple and incremental nature of the compaction hardware required. The ability of the scheme to accurately identify failing scan cells from compacted responses has been measured on production fail data from five industrial designs and is reported herein.

This paper presents a built-in self-test (BIST)-based scheme for fault diagnosis that can be used to identify permanent failures in embedded read-only memories. The proposed approach offers a simple test flow and does not require intensive interactions between a BIST controller and a tester. The scheme rests on partitioning of rows and columns of the memory array by employing low cost test logic. It is designed to meet requirements of at-speed test thus enabling detection of timing defects. Experimental results confirm high diagnostic accuracy of the proposed scheme and its time efficiency.

This paper presents a novel scheme to address the challenge of identifying failing scan cells from production test responses in the presence of scan compression. The scheme is based on a very simple test response compactor employing orthogonal - spatial and time - signatures. The advantage of this scheme as compared to previous work in this field is the simple and incremental nature of the compaction hardware required. The ability of the scheme to accurately identify failing scan cells from compacted responses has been measured on production fail data from five industrial designs and is reported herein.

Embedded memories are increasingly identified as having potential for introducing new yield loss mechanisms at a rate, magnitude, and complexity large enough to demand major changes in fault diagnosis techniques. In particular, time-related or complex read faults that originate in the highest density areas of semiconductor designs require new methods to diagnose more complex faults affecting large groups of memory cells. This paper presents a built-in self-test (BIST)-based fault diagnosis scheme that can be used to identify a variety of failures in embedded random-access memory arrays. The proposed solution employs flexible test logic to record test responses at the system speed with no interruptions of a BIST session. It offers a simple test flow and enables detection of time-related faults. Furthermore, the way test responses are processed allows accurate and time-efficient reconstruction of error bitmaps. The proposed diagnostic algorithms use a number of techniques, including discrete logarithm-based counting with ring generators acting as very fast event counters and signature analyzers. Experimental results confirm high diagnostic accuracy of the proposed scheme and its time efficiency.

The paper presents a BIST-based scheme for fault diagnosis that can be used to identify permanent and address independent failures in embedded read-only memories. The proposed approach offers a simple test flow and does not require intensive interactions between a BIST controller and a tester. The scheme rests on partitioning of rows and columns of the memory array by employing low cost test logic. It is designed to meet requirements of at-speed test thus enabling detection of time-related faults.

The paper presents a BIST-based fault diagnosis scheme that can be used to identify a variety of failures in embedded memory arrays. The proposed solution employs flexible test logic to record test responses at the system speed with no interruptions of a BIST session. It offers a simple test flow and enables detection of time-related faults. Furthermore, the way the test responses are processed allows accurate reconstruction of error bitmaps.

This paper presents new nonadaptive fault-diagnosis techniques for scan-based designs. They guarantee accurate and time-efficient identification of failing scan cells based on results of convolutional compaction of test responses. The essence of the method is to use a branch-and-bound algorithm to narrow the set of scan cells down to certain sites that are most likely to capture faulty signals. This search is guided by a number of heuristics and self-learned information used to accelerate the diagnosis process for the subsequent test patterns. A variety of experimental results for benchmark circuits, industrial designs, and real fail logs confirm the feasibility of the proposed approach even in the presence of unknown states. The scheme remains consistent with a single test session scenario and allows high-volume in-production diagnosis.

This paper introduces a new test response compaction scheme that rests on convolutional compactors. The resultant compression, however, is not limited by the ratio of scan chains to compactor outputs. This enhanced convolutional compactor, similarly to its origin, is capable of handling unknown states and detecting multiple errors. The experimental results demonstrate efficiency of the proposed scheme

This paper describes a fault diagnosis technique for scan-based designs with convolutional test response compaction. The proposed approach allows a time-efficient and accurate identification of failing scan cells using Gauss Jordan elimination method.

The paper presents non-adaptive fault diagnosis techniques for scan-based designs. These schemes guarantee accurate and time-efficient identification of failing scan cells based on results of a convolutional test response compaction in the presence of unknown states

The paper introduces a new non-adaptive fault diagnosis technique for scan-based designs. The proposed scheme guarantees accurate and time-efficient identification of failing scan cells based on results of a convolutional test response compaction.