A 1.2 V 20 nm 307 GB/s HBM DRAM With At-Speed Wafer-Level IO Test Scheme and Adaptive Refresh Considering Temperature Distribution

A 1.2 V 20 nm 307 GB/s high-bandwidth memory (HBM) DRAM is presented to satisfy a high-bandwidth requirement of high-performance computing application. The HBM is composed of buffer die and multiple core dies, and each core die has 8 Gb DRAM cell array with additional 1 Gb ECC array. At-speed wafer level, a u-bump IO test scheme and an adaptive refresh scheme considering temperature distribution are proposed to guarantee test coverage and stable operation in a power-efficient manner.