Core Viewpoint - The cooling technology will become a key competitive factor in the high bandwidth memory (HBM) market as HBM5 is expected to commercialize around 2029, shifting the focus from packaging to cooling methods [1][2]. Summary by Sections HBM Technology Roadmap - The roadmap from HBM4 to HBM8 spans from 2025 to 2040, detailing advancements in HBM architecture, cooling methods, TSV density, and interlayer technologies [1]. - HBM4 is projected to have a data rate of 8 Gbps, a bandwidth of 2.0 TB/s, and a capacity of 36/48 GB per HBM, utilizing liquid cooling methods [3]. - HBM5 will maintain the 8 Gbps data rate but will double the bandwidth to 4 TB/s and increase capacity to 80 GB [3]. - HBM6 will introduce a data rate of 16 Gbps and a bandwidth of 8 TB/s, with a capacity of 96/120 GB [3]. - HBM7 is expected to reach 24 TB/s bandwidth and 160/192 GB capacity, while HBM8 will achieve 32 Gbps data rate, 64 TB/s bandwidth, and 200/240 GB capacity [3]. Cooling Technologies - HBM5 will utilize immersion cooling, where the substrate and package are submerged in cooling liquid, addressing limitations of current liquid cooling methods [1]. - HBM7 will require embedded cooling systems to inject cooling liquid between DRAM chips, introducing fluid TSVs [2]. - The professor emphasizes that cooling will be critical as the base chip will take on part of the GPU workload starting from HBM4, leading to increased temperatures [1][2]. Bonding and Performance Factors - Bonding will also play a significant role in determining HBM performance, with mixed glass and silicon interlayers being introduced from HBM6 onwards [2].

Core Viewpoint - The cooling technology will become a key competitive factor in the high bandwidth memory (HBM) market as HBM5 is expected to commercialize around 2029, shifting the focus from packaging to cooling solutions [1][2]. Summary by Sections HBM Technology Roadmap - The roadmap from HBM4 to HBM8 spans from 2025 to 2040, detailing advancements in HBM architecture, cooling methods, TSV density, and interposer layers [1]. - HBM4 is projected to be available in 2026, with a data rate of 8 Gbps, bandwidth of 2.0 TB/s, and a capacity of 36/48 GB per HBM [3]. - HBM5, expected in 2029, will double the bandwidth to 4 TB/s and increase capacity to 80 GB [3]. - HBM6, HBM7, and HBM8 will further enhance data rates and capacities, reaching up to 32 Gbps and 240 GB respectively by 2038 [3]. Cooling Technologies - HBM5 will utilize immersion cooling, where the substrate and package are submerged in cooling liquid, addressing limitations of current liquid cooling methods [2]. - HBM7 will require embedded cooling systems to inject coolant between DRAM chips, introducing fluid TSVs for enhanced thermal management [2]. - The introduction of new types of TSVs, such as thermal TSVs and power TSVs, will support the cooling needs of future HBM generations [2]. Performance Factors - Bonding techniques will also play a crucial role in HBM performance, with HBM6 introducing a hybrid interposer of glass and silicon [2]. - The integration of advanced packaging technologies will allow base chips to take on GPU workloads, necessitating improved cooling solutions due to increased temperatures [2].