Spin-transfer-torque magnetic random access memory (STT-MRAM) is a candidate for next-generation memory to cope with scaling challenges of conventional memories. However, the STT-MRAM has a small on/off resistance ratio which poses challenges in designing the reference resistance. An effective approach to cope with this issue is to design a trimmable reference resistance that allows post-production control of the reference resistance. A trimming test should be used in the production test to find an appropriate reference resistance. In this paper, a parallel-check trimming test (PCTT) approach aimed at significantly reducing the trimming test time is proposed. In comparison with the existing binary-judge-based search test approach, the proposed PCTT approach drastically reduces trimming test time with nearly the same read yield.

Various advanced packaging technologies have been proposed to integrate multiple dies into a package. In the multidie package, a significant amount of inter-die interconnects are used to assemble the dies. The bonding interfaces, e.g., microbumps (ubumps), of the inter-die interconnects are prone to defects during the assembly process. Therefore, it is crucial to test the inter-die interconnects to ensure the quality of the assembly. In this paper, we propose an efficient built-in self-test (BIST) scheme for the testing of inter-die interconnects of chiplet-based ICs. The transmitters/receivers under test are logically arranged as a 2D array. A test algorithm that utilizes alternating row stripe and column stripe test patterns is proposed. These 2D test patterns are then compressed into 1D test patterns such that the test application time can be reduced. Simulation and analysis results show that the proposed BIST scheme can achieve 99.9% test time reduction and save about 53.5% area cost for a 32×64 ubump array in comparison with a typical test scheme, IEEE 1500 test scheme.

Distributed renewable energy has emerged as a promising resource because of its environmental friendliness and economic considerations. However, most renewable energy sources are unreliable and may require considerable effort to be efficiently utilized in a computing center for providing services. In this paper, we exploit distributed renewable energy (e.g., solar energy) and peer-to-peer (P2P) technologies to aggregate distributed computing resources to provide an infrastructure called solar-based energy-efficient distributed server (SEEDS) farm for distributed computing and distributed storage. Energy-efficient devices (e.g., embedded devices) powered by solar energy form a P2P computing system to provide their computing resources to end-users. Specifically, this paper uses a Web-based service as a case study. A group of solar-powered embedded devices acts as a front-end cooperative caching system for Web servers. Web objects may be accessed through the distributed caching system without going through servers, and thus we can reduce brown energy consumption of the servers. This paper also develops an analytical model to evaluate the total energy consumption of Web-based services with and without SEEDS. Theoretical and simulation results show that the SEEDS system can support services and achieve significant improvements in energy efficiency by aggregating distributed energy resources.