R&D: Low Power and Thermal Throttling-Less SSD with In-Package Boost Converter for 1000-WL Layer 3D Flash Memory

2023 IEEE International Memory Workshop (IMW) has published an article written by Kazuma Hasegawa, Memory Div., Kioxia Corporation, Japan, Yuta Aiba, Institute of Memory Technology Research & Development, Kioxia Corporation, Japan, Xu Li, Memory Div., Kioxia Corporation, Japan, Hitomi Tanaka, Takayuki Miyazaki, Institute of Memory Technology Research & Development, Kioxia Corporation, Japan, Hideko Mukaida, Memory Div., Kioxia Corporation, Japan, Masaru Koyanagi, Institute of Memory Technology Research & Development, Kioxia Corporation, Japan, Masayuki Miura, Memory Div., Kioxia Corporation, Japan, and Tomoya Sanuki, Institute of Memory Technology Research & Development, Kioxia Corporation, Japan.

Abstract: “Power consumption and thermal throttling of the 3D flash memory have become a prevalent issue owing to the requirement for higher performance in SSDs. One of the main causes is the on-die charge pump circuit, which has a low conversion efficiency and induces high heat generation. The heat generation becomes a critical issue due to the high-density mounting of components, especially in mobile products. In this work, we fabricated a 3D flash memory with an in-package boost converter to replace the on-die charge pump circuit. The boost converter consists of three types of discrete components: a DC-DC converter, an inductor, and capacitors. Using the in package boost converter, we show that the power consumption can be reduced by up to 39% while the temperature rise can be reduced by 50%. Furthermore, when the number of word line (WL) layers reaches 1000, a significantly large power reduction up to 43% can be achieved, resulting in 9% smaller power consumption compared to the conventional 1xx layers. The proposed in-package boost converter is an effective scheme to suppress the power consumption and heat generation and can realize the development of a thermal throttling-less SSD.“