3D-memory is one of promising applications in 3D-IC technology. With a 3D integration technology, the effective density of memories can increase and the interconnect distance from processor to memory can be shortened. Due to its stacked structure, the upper dies behave as shields blocking outer particles from reaching lower dies, and it makes error rate of the top layer largest among all layers. From a heat perspective, the lower dies would suffer from reliability problems since the lower dies are placed on top of logic die. The heat dissipation can more influence lower dies than upper dies. This creates unequal a reliability distribution for each layer in 3D-memories. A novel ECC organization scheme for 3D-memory to secure reliable operations under soft error rate (SER) profiles is introduced in this paper. The proposed scheme does not require additional redundant arrays. Instead, it utilizes unused spare columns of relatively reliable layer memories to store additional check-bits of less reliable layer memories. It forms a heterogeneous ECC organization across different layers which enhances ECC capabilities in less reliable layers. In addition, redundancy sharing scheme for yield enhancement can be implemented with the proposed scheme. Experimental results show that a memory with the proposed method can tolerate more than three times of a bit-error rate compared to the conventional memory.
Bibliographical noteFunding Information:
This work was supported in part by the Basic Science Research Program through the National Research Foundation of Korea by the Ministry of Education under Grant NRF-2015R1D1A1A01058856, in part by the Korea Institute for Advancement of Technology (KIAT) by the Korean Government (Motie:Ministry of Trade, Industry Energy, HRD Program for Software-SoC Convergence) under Grant N0001883, in part by the MOTIE (Ministry of Trade, Industry Energy (10080594) and KSRC (Korea Semiconductor Research Consortium) support program for the development of the future semiconductor device.
All Science Journal Classification (ASJC) codes
- Theoretical Computer Science
- Hardware and Architecture
- Computational Theory and Mathematics