SK Hynix is reportedly working on a new type of memory that will combine a wide interface with lower costs, when compared to HBM solutions. The new type of memory is set to use 2.5D fan-out packaging and could be used for graphics or mobile applications, reports BusinessKorea.
At the heart of SK Hynix's technology is a simple but effective idea: placing two DRAM devices side by side and merging them into one using a Fan-out Wafer-Level Packaging (FOWLP) 2.5D method. This gets rid of the need for an extra layer underneath the devices (which are used for dual-die memory devices), leading to slimmer chips and building a memory device with a wider interface.
This is a big change from the usual way of making dual- or multi-die memory chips. It shows SK Hynix's move toward newer methods that could pair wide interfaces and cost efficiency.
Modern GDDR6 and LPDDR5X memory devices feature a 32-bit or 64-bit interface, whereas HBM stacks boast a 1024-bit interface that offers a radically higher peak bandwidth despite having lower data transfer rates. However, to build an HBM device, companies like SK Hynix need to stack multiple memory devices, connect them using TSVs (through-silicon vias), place them on a base layer, and then connect them to a host processor using an interposer.
Given all the complexities, HBM is incredibly expensive. That's why its primarily used for data center and enterprise solution — and why AMD's Fiji and Vega architectures struggled to turn a profit.
By contrast, SK Hynix's DRAM built using a 2.5D FOWLP skips TSVs and omits interposers, greatly reducing its cost. Meanwhile, the resulting memory devices feature a relatively wide interface (we presume at least 128 bits) and thus higher per chip bandwidth.
One of the main reasons SK Hynix is adopting this new packaging is to cut costs, according to the report, so the new type of memory should be relatively cheap. We do not know exact costs, but we presume that they are higher than those of LPDDR and GDDR, while still being much lower than HBM.
An obvious question is whether SK Hynix's 2.5D Fan-out DRAMs are supported by any existing applications. It looks like, at least initially, the memory products will be used for very specific devices. This aligns with the company's strategy to make memory devices that are more specialized and produced in smaller quantities.
