Wafer-to-wafer bonding requires precisely matching dies, including compatible die sizes and corresponding layouts.

“Uh, one of the challenges with that though is that you need dies that perfectly match each other and are perfectly like, uh, left-handed and right-handed, right? So you have to be able to bond exactly one to the other.”

“So one-to-one die size is a challenge. So if they're not the exact same design device on top and bottom, that's a problem. So wafer to wafer, it's just challenging to make sure that you have wafers that match really well in terms of the sort, right?”