We've been hearing about "stacked" motherboards destined for iPhones for a while, and Apple is now rumored to use one in the upcoming iPhone 8, so as to free space for a larger, L-shaped battery supplied by LG. In a nutshell, those advanced SLP (Substrate Like PCB) circuit boards would stack or package the chips tighter together, making their footprint much smaller, and leaving space for other things inside a phone, like, ahem, larger batteries. That's exactly what Samsung may be doing with the Galaxy S9, tips Korean media today, referring to "industry sources".
Allegedly, four of the ten suppliers that Samsung uses for its phones' circuit boards have the ability and capacity to produce SLP designs. Does that mean that only some Galaxy S9 units will have them? Well, the source does say that Samsung will equip the Exynos versions of the S9 with the space-saving PCB tech, though not because its suppliers don't have the capacity, but rather since the versions with Qualcomm chipsets has "technical difficulties" to use the advanced system boards, at least for now.
Hopefully, that won't also translate in smaller battery packs for those, as the source expects that "application of SLP will quickly expand once initial introduction phase of SLP passes by." The S9 and S9+ will reportedly use the same screen sizes and chassis design of the S8/S8+, but have slimmer in-cell touch display packages, and, now, smaller logic boards, so we cross our fingers for larger batteries indeed.