JEDEC Ratifies 'SPHBM4' Standard; Glass Substrate Utility Draws Attention

The Joint Electron Device Engineering Council (JEDEC) has ratified a new standard that broadens the addressable scope of high bandwidth memory (HBM). Industry observers suggest that, alongside a shift in the cost structure of artificial intelligence (AI) chips, the value of glass substrate adoption could come into sharper focus.
According to JEDEC on the 21st, the new HBM4 standard, "SPHBM4 (Standard Package HBM4)," received final board approval following deliberations within the DRAM memory subcommittee (JC-42.2).
SPHBM4 is a specification designed to preserve as much of the existing HBM4 performance as possible while allowing its use with fewer signal pins and within standard packaging structures. The intent is to reduce reliance on costly advanced packaging and to broaden the addressable scope of high performance memory.
SPHBM4 targets a fourfold increase in signal speed versus HBM4, thereby cutting the required signal pin count to roughly one fifth. Its defining feature is the ability to deliver HBM class bandwidth while using standard substrates.
The interconnect topology also changes. The standard defines a connection distance of up to 20mm between the host compute die and the memory. Placing the memory farther from the compute device allows for greater flexibility in thermal management within the package.
The potential linkage with glass substrates is also drawing attention. Glass substrates are cited as a next generation packaging substrate with advantages over conventional organic substrates in thermal stability, flatness, and fine line routing. They have yet to reach commercialization, however, and securing mass production processes and cost competitiveness remains a challenge.
An industry official commented, "If glass substrates are the foundation that enables large packages, then SPHBM4 is the specification that allows HBM class memory to be deployed within them more economically," adding, "As SPHBM4 adoption widens, the utility of glass substrates could rise in tandem with demand for large packages."
The market penetration of SPHBM4 hinges on actual adoption. The significance of the standard will materialize in earnest only if memory makers such as Samsung Electronics and SK Hynix bring relevant products to market and if major players in the AI chip ecosystem, including TSMC and Nvidia, adopt them.